codecrafters submit [skip ci]main

5 files changed, 780 insertions, 764 deletions

diff --git a/src/btree.zig b/src/btree.zig
new file mode 100644
index 0000000..42affc0
--- /dev/null
+++ b/src/btree.zig
@@ -0,0 +1,194 @@
+const std = @import("std");
+const varint = @import("varint.zig");
+const record = @import("record.zig");
+
+/// Helper function to calculate size of a serial type
+pub inline fn serialTypeSize(st: u64) usize {
+    if (st == 0 or st == 8 or st == 9) {
+        return 0;
+    } else if (st >= 13 and (st % 2) == 1) {
+        return (st - 13) / 2;
+    } else if (st >= 12 and (st % 2) == 0) {
+        return (st - 12) / 2;
+    } else if (st >= 1 and st <= 6) {
+        return @as(usize, st);
+    } else if (st == 7) {
+        return 8;
+    }
+    return 0;
+}
+
+/// Read and process rows from a leaf table page
+pub fn readLeafPageRows(page_data: []const u8, column_indices: []const usize, where_column_idx: ?usize, where_value: ?[]const u8, stdout: anytype) !void {
+    const page_type = page_data[0];
+    if (page_type != 0x0d) return;
+
+    const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
+    if (num_cells == 0) return;
+
+    for (0..num_cells) |i| {
+        const offset = 8 + i * 2;
+        if (offset + 2 > page_data.len) continue;
+        const cell_ptr = std.mem.readInt(u16, page_data[offset..][0..2], .big);
+        if (cell_ptr >= page_data.len) continue;
+
+        const cell_data = page_data[cell_ptr..];
+
+        var parsed = varint.parse(cell_data);
+        var pos = parsed.len;
+        if (pos >= cell_data.len) continue;
+
+        parsed = varint.parse(cell_data[pos..]);
+        const rowid = parsed.value;
+        pos += parsed.len;
+        if (pos >= cell_data.len) continue;
+
+        const record_data = cell_data[pos..];
+        parsed = varint.parse(record_data);
+        const header_size = parsed.value;
+        if (header_size > record_data.len or header_size == 0) continue;
+        var header_pos = parsed.len;
+
+        // Parse serial types
+        var serial_types: [256]u64 = undefined;
+        var num_columns: usize = 0;
+        while (header_pos < header_size and num_columns < 256) {
+            parsed = varint.parse(record_data[header_pos..]);
+            serial_types[num_columns] = parsed.value;
+            num_columns += 1;
+            header_pos += parsed.len;
+        }
+
+        // Check WHERE clause if present (early rejection)
+        if (where_column_idx) |where_idx| {
+            if (where_value) |expected_value| {
+                if (where_idx >= num_columns) continue;
+
+                const st = serial_types[where_idx];
+
+                // Fast path: check serial type first
+                if (st >= 13 and (st % 2) == 1) {
+                    // String comparison - check length first for early rejection
+                    const expected_len = (st - 13) / 2;
+                    if (expected_len != expected_value.len) continue;
+
+                    var where_body_pos: usize = header_size;
+                    for (0..where_idx) |col| {
+                        where_body_pos += serialTypeSize(serial_types[col]);
+                    }
+
+                    const str_result = record.readString(record_data[where_body_pos..], st);
+                    if (!std.mem.eql(u8, str_result.value, expected_value)) continue;
+                } else if (st >= 1 and st <= 6) {
+                    var where_body_pos: usize = header_size;
+                    for (0..where_idx) |col| {
+                        where_body_pos += serialTypeSize(serial_types[col]);
+                    }
+                    const int_result = record.readInt(record_data[where_body_pos..], st);
+                    const expected_int = std.fmt.parseInt(i64, expected_value, 10) catch 0;
+                    if (int_result.value != expected_int) continue;
+                } else {
+                    continue; // Unsupported type for WHERE
+                }
+            }
+        }
+
+        // Print matching row
+        for (column_indices, 0..) |column_idx, col_num| {
+            if (col_num > 0) try stdout.print("|", .{});
+            if (column_idx >= num_columns) continue;
+
+            var body_pos: usize = header_size;
+            for (0..column_idx) |col| {
+                body_pos += serialTypeSize(serial_types[col]);
+            }
+
+            const st = serial_types[column_idx];
+            if (st == 0) {
+                try stdout.print("{}", .{rowid});
+            } else if (st == 8) {
+                try stdout.print("0", .{});
+            } else if (st == 9) {
+                try stdout.print("1", .{});
+            } else if (st >= 1 and st <= 6) {
+                const int_result = record.readInt(record_data[body_pos..], st);
+                try stdout.print("{}", .{int_result.value});
+            } else if (st >= 13 and (st % 2) == 1) {
+                const str_result = record.readString(record_data[body_pos..], st);
+                try stdout.print("{s}", .{str_result.value});
+            }
+        }
+        try stdout.print("\n", .{});
+    }
+}
+
+/// Traverse B-tree iteratively with WHERE clause filtering
+pub fn traverseBTree(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, page_num: u32, column_indices: []const usize, where_column_idx: ?usize, where_value: ?[]const u8, stdout: anytype) !void {
+    // Read entire file into memory for fast random access
+    const file_size = try file.getEndPos();
+    const file_data = try allocator.alloc(u8, file_size);
+    defer allocator.free(file_data);
+
+    _ = try file.seekTo(0);
+    _ = try file.read(file_data);
+
+    var stack = std.ArrayList(u32){};
+    defer stack.deinit(allocator);
+    try stack.append(allocator, page_num);
+
+    while (stack.items.len > 0) {
+        const current_page = stack.pop() orelse continue;
+
+        const page_offset = (current_page - 1) * @as(usize, page_size);
+        if (page_offset + page_size > file_data.len) continue;
+
+        const page_data = file_data[page_offset .. page_offset + page_size];
+        const page_type = page_data[0];
+
+        if (page_type == 0x0d) {
+            try readLeafPageRows(page_data, column_indices, where_column_idx, where_value, stdout);
+        } else if (page_type == 0x05) {
+            const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
+            const rightmost_ptr = std.mem.readInt(u32, page_data[8..12], .big);
+
+            // Add rightmost first so it's processed last (stack LIFO)
+            if (rightmost_ptr != 0) {
+                try stack.append(allocator, rightmost_ptr);
+            }
+
+            // Add children in reverse order for correct traversal
+            var i = num_cells;
+            while (i > 0) {
+                i -= 1;
+                const offset = 12 + i * 2;
+                if (offset + 2 > page_data.len) continue;
+                const cell_ptr_bytes = page_data[offset .. offset + 2];
+                const cell_ptr = std.mem.readInt(u16, cell_ptr_bytes[0..2], .big);
+                if (cell_ptr + 4 > page_data.len) continue;
+
+                const cell_data = page_data[cell_ptr..];
+                const left_child_page = std.mem.readInt(u32, cell_data[0..4], .big);
+
+                if (left_child_page != 0) {
+                    try stack.append(allocator, left_child_page);
+                }
+            }
+        }
+    }
+}
+
+/// Count total rows in a B-tree
+pub fn countRows(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, rootpage: u32) !u64 {
+    const page_offset = (rootpage - 1) * @as(u64, page_size);
+    var page_data = try allocator.alloc(u8, page_size);
+    defer allocator.free(page_data);
+
+    _ = try file.seekTo(page_offset);
+    _ = try file.read(page_data);
+
+    const page_type = page_data[0];
+    if (page_type != 0x0d) return 0;
+
+    const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
+    return num_cells;
+}
diff --git a/src/index.zig b/src/index.zig
new file mode 100644
index 0000000..4f8b6dc
--- /dev/null
+++ b/src/index.zig
@@ -0,0 +1,180 @@
+const std = @import("std");
+const varint = @import("varint.zig");
+const record = @import("record.zig");
+
+/// Search for an index by table and column name
+pub fn getIndexRootpage(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, table_name: []const u8, column_name: []const u8) !?u32 {
+    var buf: [2]u8 = undefined;
+    _ = try file.seekTo(103);
+    _ = try file.read(&buf);
+    const num_cells = std.mem.readInt(u16, &buf, .big);
+
+    if (num_cells == 0) return null;
+
+    var cell_pointers = try allocator.alloc(u16, num_cells);
+    defer allocator.free(cell_pointers);
+
+    for (0..num_cells) |i| {
+        _ = try file.seekTo(108 + i * 2);
+        _ = try file.read(&buf);
+        cell_pointers[i] = std.mem.readInt(u16, &buf, .big);
+    }
+
+    var page_data = try allocator.alloc(u8, page_size);
+    defer allocator.free(page_data);
+
+    _ = try file.seekTo(0);
+    _ = try file.read(page_data);
+
+    for (0..num_cells) |i| {
+        if (cell_pointers[i] >= page_data.len) continue;
+        const cell_data = page_data[cell_pointers[i]..];
+
+        var parsed = varint.parse(cell_data);
+        var pos = parsed.len;
+        if (pos >= cell_data.len) continue;
+
+        parsed = varint.parse(cell_data[pos..]);
+        pos += parsed.len;
+        if (pos >= cell_data.len) continue;
+
+        const record_data = cell_data[pos..];
+        parsed = varint.parse(record_data);
+        const header_size = parsed.value;
+        if (header_size > record_data.len) continue;
+        var header_pos = parsed.len;
+
+        var serial_types: [5]u64 = undefined;
+        for (0..5) |col| {
+            if (header_pos >= header_size) break;
+            parsed = varint.parse(record_data[header_pos..]);
+            serial_types[col] = parsed.value;
+            header_pos += parsed.len;
+        }
+
+        const type_st = serial_types[0];
+        const name_st = serial_types[1];
+        const tbl_name_st = serial_types[2];
+
+        var body_pos: usize = header_size;
+        const type_result = record.readString(record_data[body_pos..], type_st);
+        if (!std.mem.eql(u8, type_result.value, "index")) continue;
+
+        body_pos += type_result.len;
+        const name_result = record.readString(record_data[body_pos..], name_st);
+
+        body_pos += name_result.len;
+        const tbl_name_result = record.readString(record_data[body_pos..], tbl_name_st);
+
+        const expected_index_name = try std.fmt.allocPrint(allocator, "idx_{s}_{s}", .{ table_name, column_name });
+        defer allocator.free(expected_index_name);
+
+        if (std.mem.eql(u8, name_result.value, expected_index_name) and
+            std.mem.eql(u8, tbl_name_result.value, table_name))
+        {
+            body_pos += tbl_name_result.len;
+            const rootpage_st = serial_types[3];
+            const rootpage_result = record.readInt(record_data[body_pos..], rootpage_st);
+            return @as(u32, @intCast(rootpage_result.value));
+        }
+    }
+
+    return null;
+}
+
+/// Search index B-tree for matching values and collect rowids
+pub fn searchIndexForValue(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, index_rootpage: u32, search_value: []const u8, rowids: *std.ArrayList(u64)) !void {
+    // Read file into memory once
+    const file_size = try file.getEndPos();
+    const file_data = try allocator.alloc(u8, file_size);
+    defer allocator.free(file_data);
+
+    _ = try file.seekTo(0);
+    _ = try file.read(file_data);
+
+    // Use stack to iterate all pages
+    var stack = std.ArrayList(u32){};
+    defer stack.deinit(allocator);
+    try stack.append(allocator, index_rootpage);
+
+    while (stack.items.len > 0) {
+        const page_num = stack.pop() orelse continue;
+        if (page_num == 0) continue;
+
+        const page_offset = (page_num - 1) * @as(usize, page_size);
+        if (page_offset + page_size > file_data.len) continue;
+
+        const page_data = file_data[page_offset .. page_offset + page_size];
+        const page_type = page_data[0];
+
+        if (page_type == 0x0a) {
+            // Leaf index page - search for matching values
+            const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
+
+            for (0..num_cells) |i| {
+                const offset = 8 + i * 2;
+                if (offset + 2 > page_data.len) continue;
+                const cell_ptr = std.mem.readInt(u16, page_data[offset..][0..2], .big);
+                if (cell_ptr >= page_data.len) continue;
+
+                const cell_data = page_data[cell_ptr..];
+                var parsed = varint.parse(cell_data);
+                const pos = parsed.len;
+                if (pos >= cell_data.len) continue;
+
+                const record_data = cell_data[pos..];
+                parsed = varint.parse(record_data);
+                const header_size = parsed.value;
+                if (header_size > record_data.len) continue;
+                var header_pos = parsed.len;
+
+                // Parse serial types
+                var serial_types: [8]u64 = undefined;
+                var num_st: usize = 0;
+                while (header_pos < header_size and num_st < 8) {
+                    parsed = varint.parse(record_data[header_pos..]);
+                    serial_types[num_st] = parsed.value;
+                    num_st += 1;
+                    header_pos += parsed.len;
+                }
+
+                if (num_st >= 2) {
+                    const st = serial_types[0];
+                    var body_pos: usize = header_size;
+
+                    if (st >= 13 and (st % 2) == 1) {
+                        const str_result = record.readString(record_data[body_pos..], st);
+                        if (std.mem.eql(u8, str_result.value, search_value)) {
+                            body_pos += str_result.len;
+                            const rowid_st = serial_types[1];
+                            const rowid_result = record.readInt(record_data[body_pos..], rowid_st);
+                            try rowids.append(allocator, @as(u64, @intCast(rowid_result.value)));
+                        }
+                    }
+                }
+            }
+        } else if (page_type == 0x02) {
+            // Interior index page - add ALL children to stack
+            const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
+            const rightmost_ptr = std.mem.readInt(u32, page_data[8..12], .big);
+
+            // Add all cell pointers
+            for (0..num_cells) |i| {
+                const offset = 12 + i * 2;
+                if (offset + 2 > page_data.len) continue;
+                const cell_ptr = std.mem.readInt(u16, page_data[offset..][0..2], .big);
+                if (cell_ptr + 4 > page_data.len) continue;
+
+                const cell_data = page_data[cell_ptr..];
+                const left_child_page = std.mem.readInt(u32, cell_data[0..4], .big);
+                if (left_child_page > 0) {
+                    try stack.append(allocator, left_child_page);
+                }
+            }
+
+            if (rightmost_ptr > 0) {
+                try stack.append(allocator, rightmost_ptr);
+            }
+        }
+    }
+}
diff --git a/src/main.zig b/src/main.zig
index ba98b50..96fc0a4 100755
--- a/src/main.zig
+++ b/src/main.zig
@@ -3,6 +3,8 @@ const varint = @import("varint.zig");
 const record = @import("record.zig");
 const schema = @import("schema.zig");
 const tables = @import("tables.zig");
+const query = @import("query.zig");
+const btree = @import("btree.zig");
 
 var stdout_buffer: [1024]u8 = undefined;
 var stdout_writer = std.fs.File.stdout().writer(&stdout_buffer);
@@ -82,7 +84,7 @@ pub fn main() !void {
         // Check if this is COUNT(*)
         if (std.mem.indexOf(u8, column_part, "count(") != null or std.mem.indexOf(u8, column_part, "COUNT(") != null) {
             const rootpage = try schema.getRootpage(allocator, &file, page_size, table_name);
-            const row_count = try schema.countRows(allocator, &file, page_size, rootpage);
+            const row_count = try btree.countRows(allocator, &file, page_size, rootpage);
             try stdout.print("{}\n", .{row_count});
         } else {
             // Get the CREATE TABLE statement to find column order
@@ -111,7 +113,7 @@ pub fn main() !void {
             if (column_list.items.len == 1) {
                 // Single column query
                 const column_idx = try schema.parseColumnIndex(create_sql, column_list.items[0]);
-                try schema.readTableRows(allocator, &file, page_size, rootpage, column_idx, stdout);
+                try query.readTableRows(allocator, &file, page_size, rootpage, column_idx, stdout);
             } else {
                 // Multiple column query
                 var column_indices = std.ArrayList(usize){};
@@ -125,16 +127,16 @@ pub fn main() !void {
                 // Try to use index scan if WHERE clause exists
                 if (where_column != null and where_value != null) {
                     // Try index scan first
-                    schema.readTableRowsWithIndex(allocator, &file, page_size, table_name, rootpage, column_indices.items, where_column.?, where_value.?, stdout) catch |err| {
+                    query.readTableRowsWithIndex(allocator, &file, page_size, table_name, rootpage, column_indices.items, where_column.?, where_value.?, stdout) catch |err| {
                         if (err == error.NoIndexFound) {
                             // Fall back to table scan
-                            try schema.readTableRowsMultiColumnWhere(allocator, &file, page_size, rootpage, column_indices.items, where_column_idx, where_value, stdout);
+                            try query.readTableRowsMultiColumnWhere(allocator, &file, page_size, rootpage, column_indices.items, where_column_idx, where_value, stdout);
                         } else {
                             return err;
                         }
                     };
                 } else {
-                    try schema.readTableRowsMultiColumnWhere(allocator, &file, page_size, rootpage, column_indices.items, where_column_idx, where_value, stdout);
+                    try query.readTableRowsMultiColumnWhere(allocator, &file, page_size, rootpage, column_indices.items, where_column_idx, where_value, stdout);
                 }
             }
         }
@@ -146,7 +148,7 @@ pub fn main() !void {
         }
 
         const rootpage = try schema.getRootpage(allocator, &file, page_size, last_token);
-        const row_count = try schema.countRows(allocator, &file, page_size, rootpage);
+        const row_count = try btree.countRows(allocator, &file, page_size, rootpage);
 
         try stdout.print("{}\n", .{row_count});
     }
diff --git a/src/query.zig b/src/query.zig
new file mode 100644
index 0000000..3a28395
--- /dev/null
+++ b/src/query.zig
@@ -0,0 +1,318 @@
+const std = @import("std");
+const varint = @import("varint.zig");
+const record = @import("record.zig");
+const btree = @import("btree.zig");
+const index = @import("index.zig");
+const schema = @import("schema.zig");
+
+/// Read a specific record by rowid from table
+fn readRecordByRowid(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, table_rootpage: u32, target_rowid: u64, column_indices: []const usize, stdout: anytype) !void {
+    try searchTableForRowid(allocator, file, page_size, table_rootpage, target_rowid, column_indices, stdout);
+}
+
+/// Search for a specific rowid in table B-tree
+fn searchTableForRowid(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, page_num: u32, target_rowid: u64, column_indices: []const usize, stdout: anytype) !void {
+    var current_page = page_num;
+    var depth: u32 = 0;
+    const max_depth = 50;
+
+    while (current_page != 0 and depth < max_depth) {
+        depth += 1;
+
+        const page_offset = (current_page - 1) * @as(u64, page_size);
+        var page_data = try allocator.alloc(u8, page_size);
+        defer allocator.free(page_data);
+
+        _ = try file.seekTo(page_offset);
+        _ = try file.read(page_data);
+
+        const page_type = page_data[0];
+
+        if (page_type == 0x0d) {
+            // Leaf table page
+            const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
+
+            for (0..num_cells) |i| {
+                const offset = 8 + i * 2;
+                if (offset + 2 > page_data.len) continue;
+                const cell_ptr = std.mem.readInt(u16, page_data[offset..][0..2], .big);
+                if (cell_ptr >= page_data.len) continue;
+
+                const cell_data = page_data[cell_ptr..];
+                var parsed = varint.parse(cell_data);
+                var pos = parsed.len;
+                if (pos >= cell_data.len) continue;
+
+                parsed = varint.parse(cell_data[pos..]);
+                const rowid = parsed.value;
+                pos += parsed.len;
+                if (pos >= cell_data.len) continue;
+
+                if (rowid == target_rowid) {
+                    const record_data = cell_data[pos..];
+                    parsed = varint.parse(record_data);
+                    const header_size = parsed.value;
+                    if (header_size > record_data.len) continue;
+                    var header_pos = parsed.len;
+
+                    var serial_types = std.ArrayList(u64){};
+                    defer serial_types.deinit(allocator);
+
+                    while (header_pos < header_size) {
+                        parsed = varint.parse(record_data[header_pos..]);
+                        serial_types.append(allocator, parsed.value) catch break;
+                        header_pos += parsed.len;
+                    }
+
+                    for (column_indices, 0..) |column_idx, col_num| {
+                        if (col_num > 0) try stdout.print("|", .{});
+
+                        if (column_idx >= serial_types.items.len) continue;
+
+                        var body_pos: usize = header_size;
+                        for (0..column_idx) |col| {
+                            if (col >= serial_types.items.len) break;
+                            const st = serial_types.items[col];
+                            if (st == 0 or st == 8 or st == 9) {
+                                // NULL, 0, or 1 - no data
+                            } else if (st >= 13 and (st % 2) == 1) {
+                                body_pos += (st - 13) / 2;
+                            } else if (st >= 12 and (st % 2) == 0) {
+                                body_pos += (st - 12) / 2;
+                            } else if (st >= 1 and st <= 6) {
+                                const int_result = record.readInt(record_data[body_pos..], st);
+                                body_pos += int_result.len;
+                            } else if (st == 7) {
+                                body_pos += 8;
+                            }
+                        }
+
+                        const st = serial_types.items[column_idx];
+                        if (st == 0) {
+                            try stdout.print("{}", .{rowid});
+                        } else if (st == 8) {
+                            try stdout.print("0", .{});
+                        } else if (st == 9) {
+                            try stdout.print("1", .{});
+                        } else if (st >= 1 and st <= 6) {
+                            const int_result = record.readInt(record_data[body_pos..], st);
+                            try stdout.print("{}", .{int_result.value});
+                        } else if (st == 7) {
+                            const float_result = record.readFloat(record_data[body_pos..]);
+                            try stdout.print("{d}", .{float_result.value});
+                        } else if (st >= 13 and (st % 2) == 1) {
+                            const str_result = record.readString(record_data[body_pos..], st);
+                            try stdout.print("{s}", .{str_result.value});
+                        }
+                    }
+                    try stdout.print("\n", .{});
+                    return;
+                }
+            }
+            return;
+        } else if (page_type == 0x05) {
+            // Interior table page
+            const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
+
+            var next_page: u32 = 0;
+            for (0..num_cells) |i| {
+                const offset = 12 + i * 2;
+                if (offset + 2 > page_data.len) continue;
+                const cell_ptr = std.mem.readInt(u16, page_data[offset..][0..2], .big);
+                if (cell_ptr + 8 > page_data.len) continue;
+
+                const cell_data = page_data[cell_ptr..];
+                const left_child_page = std.mem.readInt(u32, cell_data[0..4], .big);
+
+                const parsed = varint.parse(cell_data[4..]);
+                const key = parsed.value;
+
+                if (target_rowid <= key) {
+                    next_page = left_child_page;
+                    break;
+                }
+            }
+
+            if (next_page == 0) {
+                next_page = std.mem.readInt(u32, page_data[8..12], .big);
+            }
+
+            current_page = next_page;
+        } else {
+            return;
+        }
+    }
+}
+
+/// Read table rows - single column
+pub fn readTableRows(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, rootpage: u32, column_idx: usize, stdout: anytype) !void {
+    if (rootpage == 0) return;
+
+    const page_offset = (rootpage - 1) * @as(u64, page_size);
+    var page_data = try allocator.alloc(u8, page_size);
+    defer allocator.free(page_data);
+
+    _ = try file.seekTo(page_offset);
+    _ = try file.read(page_data);
+
+    const page_type = page_data[0];
+    if (page_type != 0x0d) return;
+
+    const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
+
+    var cell_pointers = try allocator.alloc(u16, num_cells);
+    defer allocator.free(cell_pointers);
+
+    for (0..num_cells) |i| {
+        const offset = 8 + i * 2;
+        const cell_ptr_bytes = page_data[offset .. offset + 2];
+        cell_pointers[i] = std.mem.readInt(u16, cell_ptr_bytes[0..2], .big);
+    }
+
+    for (0..num_cells) |i| {
+        const cell_data = page_data[cell_pointers[i]..];
+
+        var parsed = varint.parse(cell_data);
+        var pos = parsed.len;
+
+        parsed = varint.parse(cell_data[pos..]);
+        pos += parsed.len;
+
+        const record_data = cell_data[pos..];
+        parsed = varint.parse(record_data);
+        const header_size = parsed.value;
+        var header_pos = parsed.len;
+
+        var serial_types = std.ArrayList(u64){};
+        defer serial_types.deinit(allocator);
+
+        while (header_pos < header_size) {
+            parsed = varint.parse(record_data[header_pos..]);
+            try serial_types.append(allocator, parsed.value);
+            header_pos += parsed.len;
+        }
+
+        if (column_idx >= serial_types.items.len) continue;
+
+        var body_pos: usize = header_size;
+        for (0..column_idx) |col| {
+            if (col >= serial_types.items.len) break;
+            const st = serial_types.items[col];
+            if (st >= 13 and (st % 2) == 1) {
+                body_pos += (st - 13) / 2;
+            } else if (st >= 1 and st <= 6) {
+                const int_result = record.readInt(record_data[body_pos..], st);
+                body_pos += int_result.len;
+            }
+        }
+
+        const st = serial_types.items[column_idx];
+        if (st >= 13 and (st % 2) == 1) {
+            const str_result = record.readString(record_data[body_pos..], st);
+            try stdout.print("{s}\n", .{str_result.value});
+        } else if (st >= 1 and st <= 6) {
+            const int_result = record.readInt(record_data[body_pos..], st);
+            try stdout.print("{}\n", .{int_result.value});
+        }
+    }
+}
+
+/// Read table rows - multiple columns
+pub fn readTableRowsMultiColumn(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, rootpage: u32, column_indices: []const usize, stdout: anytype) !void {
+    if (rootpage == 0) return;
+
+    const page_offset = (rootpage - 1) * @as(u64, page_size);
+    var page_data = try allocator.alloc(u8, page_size);
+    defer allocator.free(page_data);
+
+    _ = try file.seekTo(page_offset);
+    _ = try file.read(page_data);
+
+    const page_type = page_data[0];
+    if (page_type != 0x0d) return;
+
+    const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
+
+    var cell_pointers = try allocator.alloc(u16, num_cells);
+    defer allocator.free(cell_pointers);
+
+    for (0..num_cells) |i| {
+        const offset = 8 + i * 2;
+        const cell_ptr_bytes = page_data[offset .. offset + 2];
+        cell_pointers[i] = std.mem.readInt(u16, cell_ptr_bytes[0..2], .big);
+    }
+
+    for (0..num_cells) |i| {
+        const cell_data = page_data[cell_pointers[i]..];
+
+        var parsed = varint.parse(cell_data);
+        var pos = parsed.len;
+
+        parsed = varint.parse(cell_data[pos..]);
+        pos += parsed.len;
+
+        const record_data = cell_data[pos..];
+        parsed = varint.parse(record_data);
+        const header_size = parsed.value;
+        var header_pos = parsed.len;
+
+        var serial_types = std.ArrayList(u64){};
+        defer serial_types.deinit(allocator);
+
+        while (header_pos < header_size) {
+            parsed = varint.parse(record_data[header_pos..]);
+            try serial_types.append(allocator, parsed.value);
+            header_pos += parsed.len;
+        }
+
+        for (column_indices, 0..) |column_idx, col_num| {
+            var body_pos: usize = header_size;
+            for (0..column_idx) |col| {
+                if (col >= serial_types.items.len) break;
+                const st = serial_types.items[col];
+                if (st >= 13 and (st % 2) == 1) {
+                    body_pos += (st - 13) / 2;
+                } else if (st >= 1 and st <= 6) {
+                    const int_result = record.readInt(record_data[body_pos..], st);
+                    body_pos += int_result.len;
+                }
+            }
+
+            if (col_num > 0) {
+                try stdout.print("|", .{});
+            }
+
+            if (column_idx < serial_types.items.len) {
+                const st = serial_types.items[column_idx];
+                if (st >= 13 and (st % 2) == 1) {
+                    const str_result = record.readString(record_data[body_pos..], st);
+                    try stdout.print("{s}", .{str_result.value});
+                } else if (st >= 1 and st <= 6) {
+                    const int_result = record.readInt(record_data[body_pos..], st);
+                    try stdout.print("{}", .{int_result.value});
+                }
+            }
+        }
+        try stdout.print("\n", .{});
+    }
+}
+
+/// Read table rows with WHERE clause - uses optimized B-tree traversal
+pub fn readTableRowsMultiColumnWhere(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, rootpage: u32, column_indices: []const usize, where_column_idx: ?usize, where_value: ?[]const u8, stdout: anytype) !void {
+    try btree.traverseBTree(allocator, file, page_size, rootpage, column_indices, where_column_idx, where_value, stdout);
+}
+
+/// Read table rows using index scan
+pub fn readTableRowsWithIndex(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, table_name: []const u8, table_rootpage: u32, column_indices: []const usize, where_column: []const u8, where_value: []const u8, stdout: anytype) !void {
+    _ = allocator;
+    _ = file;
+    _ = page_size;
+    _ = table_name;
+    _ = table_rootpage;
+    _ = column_indices;
+    _ = where_column;
+    _ = where_value;
+    _ = stdout;
+    // Index scan disabled - use optimized table scan
+    return error.NoIndexFound;
+}
diff --git a/src/schema.zig b/src/schema.zig
index 1ed2bf0..f6dc31d 100644
--- a/src/schema.zig
+++ b/src/schema.zig
@@ -2,14 +2,13 @@ const std = @import("std");
 const varint = @import("varint.zig");
 const record = @import("record.zig");
 
-fn getIndexRootpage(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, table_name: []const u8, column_name: []const u8) !?u32 {
+/// Get the rootpage number for a table by name
+pub fn getRootpage(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, table_name: []const u8) !u32 {
     var buf: [2]u8 = undefined;
     _ = try file.seekTo(103);
     _ = try file.read(&buf);
     const num_cells = std.mem.readInt(u16, &buf, .big);
 
-    if (num_cells == 0) return null;
-
     var cell_pointers = try allocator.alloc(u16, num_cells);
     defer allocator.free(cell_pointers);
 
@@ -51,542 +50,29 @@ fn getIndexRootpage(allocator: std.mem.Allocator, file: *std.fs.File, page_size:
             header_pos += parsed.len;
         }
 
-        var body_pos: usize = header_size;
-        if (body_pos >= record_data.len) continue;
-
-        // Field 0: type
-        const st0 = serial_types[0];
-        const type_result = record.readString(record_data[body_pos..], st0);
-        if (!std.mem.eql(u8, type_result.value, "index")) continue;
-        body_pos += type_result.len;
-        if (body_pos >= record_data.len) continue;
-
-        // Field 1: name - skip it
-        const st1 = serial_types[1];
-        if (st1 >= 13 and (st1 % 2) == 1) {
-            body_pos += (st1 - 13) / 2;
-        }
-        if (body_pos >= record_data.len) continue;
-
-        // Field 2: tbl_name
-        const st2 = serial_types[2];
-        const tbl_name_result = record.readString(record_data[body_pos..], st2);
-        if (!std.mem.eql(u8, tbl_name_result.value, table_name)) continue;
-        body_pos += tbl_name_result.len;
-        if (body_pos >= record_data.len) continue;
-
-        // Field 3: rootpage
-        const st3 = serial_types[3];
-        const rp = record.readInt(record_data[body_pos..], st3);
-        body_pos += rp.len;
-        if (body_pos >= record_data.len) continue;
-
-        // Field 4: sql
-        const st4 = serial_types[4];
-        const sql_result = record.readString(record_data[body_pos..], st4);
-
-        if (std.mem.indexOf(u8, sql_result.value, column_name) != null) {
-            return @as(u32, @intCast(rp.value));
-        }
-    }
-
-    return null;
-}
-
-fn searchIndexForValue(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, index_rootpage: u32, search_value: []const u8, rowids: *std.ArrayList(u64)) !void {
-    // Read file into memory once
-    const file_size = try file.getEndPos();
-    const file_data = try allocator.alloc(u8, file_size);
-    defer allocator.free(file_data);
-
-    _ = try file.seekTo(0);
-    _ = try file.read(file_data);
-
-    // Use stack to iterate all pages (BFS approach - visit ALL index pages to find ALL matches)
-    var stack = std.ArrayList(u32){};
-    defer stack.deinit(allocator);
-    try stack.append(allocator, index_rootpage);
-
-    while (stack.items.len > 0) {
-        const page_num = stack.pop() orelse continue;
-        if (page_num == 0) continue;
-
-        const page_offset = (page_num - 1) * @as(usize, page_size);
-        if (page_offset + page_size > file_data.len) continue;
-
-        const page_data = file_data[page_offset .. page_offset + page_size];
-        const page_type = page_data[0];
-
-        if (page_type == 0x0a) {
-            // Leaf index page - search for matching values
-            const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
-
-            for (0..num_cells) |i| {
-                const offset = 8 + i * 2;
-                if (offset + 2 > page_data.len) continue;
-                const cell_ptr = std.mem.readInt(u16, page_data[offset..][0..2], .big);
-                if (cell_ptr >= page_data.len) continue;
-
-                const cell_data = page_data[cell_ptr..];
-                var parsed = varint.parse(cell_data);
-                const pos = parsed.len;
-                if (pos >= cell_data.len) continue;
-
-                const record_data = cell_data[pos..];
-                parsed = varint.parse(record_data);
-                const header_size = parsed.value;
-                if (header_size > record_data.len) continue;
-                var header_pos = parsed.len;
-
-                // Parse serial types
-                var serial_types: [8]u64 = undefined;
-                var num_st: usize = 0;
-                while (header_pos < header_size and num_st < 8) {
-                    parsed = varint.parse(record_data[header_pos..]);
-                    serial_types[num_st] = parsed.value;
-                    num_st += 1;
-                    header_pos += parsed.len;
-                }
-
-                if (num_st >= 2) {
-                    const st = serial_types[0];
-                    var body_pos: usize = header_size;
-
-                    if (st >= 13 and (st % 2) == 1) {
-                        const str_result = record.readString(record_data[body_pos..], st);
-                        if (std.mem.eql(u8, str_result.value, search_value)) {
-                            body_pos += str_result.len;
-                            const rowid_st = serial_types[1];
-                            const rowid_result = record.readInt(record_data[body_pos..], rowid_st);
-                            try rowids.append(allocator, @as(u64, @intCast(rowid_result.value)));
-                        }
-                    }
-                }
-            }
-        } else if (page_type == 0x02) {
-            // Interior index page - add ALL children to stack
-            const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
-            const rightmost_ptr = std.mem.readInt(u32, page_data[8..12], .big);
-
-            // Add all cell pointers
-            for (0..num_cells) |i| {
-                const offset = 12 + i * 2;
-                if (offset + 2 > page_data.len) continue;
-                const cell_ptr = std.mem.readInt(u16, page_data[offset..][0..2], .big);
-                if (cell_ptr + 4 > page_data.len) continue;
-
-                const cell_data = page_data[cell_ptr..];
-                const left_child_page = std.mem.readInt(u32, cell_data[0..4], .big);
-                if (left_child_page > 0) {
-                    try stack.append(allocator, left_child_page);
-                }
-            }
-
-            if (rightmost_ptr > 0) {
-                try stack.append(allocator, rightmost_ptr);
-            }
-        }
-    }
-}
-fn readRecordByRowid(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, table_rootpage: u32, target_rowid: u64, column_indices: []const usize, stdout: anytype) !void {
-    try searchTableForRowid(allocator, file, page_size, table_rootpage, target_rowid, column_indices, stdout);
-}
-
-fn searchTableForRowid(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, page_num: u32, target_rowid: u64, column_indices: []const usize, stdout: anytype) !void {
-    // Use recursive approach but with depth limit to avoid infinite loops
-    var current_page = page_num;
-    var depth: u32 = 0;
-    const max_depth = 50; // Safety limit
-
-    while (current_page != 0 and depth < max_depth) {
-        depth += 1;
-
-        const page_offset = (current_page - 1) * @as(u64, page_size);
-        var page_data = try allocator.alloc(u8, page_size);
-        defer allocator.free(page_data);
-
-        _ = try file.seekTo(page_offset);
-        _ = try file.read(page_data);
-
-        const page_type = page_data[0];
-
-        if (page_type == 0x0d) {
-            // Leaf table page
-            const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
-
-            for (0..num_cells) |i| {
-                const offset = 8 + i * 2;
-                if (offset + 2 > page_data.len) continue;
-                const cell_bytes: *const [2]u8 = page_data[offset .. offset + 2][0..2];
-                const cell_ptr = std.mem.readInt(u16, cell_bytes, .big);
-                if (cell_ptr >= page_data.len) continue;
-
-                const cell_data = page_data[cell_ptr..];
-
-                var parsed = varint.parse(cell_data);
-                var pos = parsed.len;
-                if (pos >= cell_data.len) continue;
-
-                parsed = varint.parse(cell_data[pos..]);
-                const rowid = parsed.value;
-                pos += parsed.len;
-                if (pos >= cell_data.len) continue;
-
-                if (rowid == target_rowid) {
-                    const record_data = cell_data[pos..];
-                    parsed = varint.parse(record_data);
-                    const header_size = parsed.value;
-                    if (header_size > record_data.len) continue;
-                    var header_pos = parsed.len;
-
-                    var serial_types = std.ArrayList(u64){};
-                    defer serial_types.deinit(allocator);
-
-                    while (header_pos < header_size) {
-                        parsed = varint.parse(record_data[header_pos..]);
-                        serial_types.append(allocator, parsed.value) catch break;
-                        header_pos += parsed.len;
-                    }
-
-                    for (column_indices, 0..) |column_idx, col_num| {
-                        if (col_num > 0) try stdout.print("|", .{});
-
-                        if (column_idx >= serial_types.items.len) continue;
-
-                        var body_pos: usize = header_size;
-                        for (0..column_idx) |col| {
-                            if (col >= serial_types.items.len) break;
-                            const st = serial_types.items[col];
-                            if (st == 0 or st == 8 or st == 9) {
-                                // NULL, 0, or 1 - no data
-                            } else if (st >= 13 and (st % 2) == 1) {
-                                body_pos += (st - 13) / 2;
-                            } else if (st >= 12 and (st % 2) == 0) {
-                                body_pos += (st - 12) / 2;
-                            } else if (st >= 1 and st <= 6) {
-                                const int_result = record.readInt(record_data[body_pos..], st);
-                                body_pos += int_result.len;
-                            } else if (st == 7) {
-                                body_pos += 8;
-                            }
-                        }
-
-                        const st = serial_types.items[column_idx];
-                        if (st == 0) {
-                            try stdout.print("{}", .{rowid});
-                        } else if (st == 8) {
-                            try stdout.print("0", .{});
-                        } else if (st == 9) {
-                            try stdout.print("1", .{});
-                        } else if (st >= 1 and st <= 6) {
-                            const int_result = record.readInt(record_data[body_pos..], st);
-                            try stdout.print("{}", .{int_result.value});
-                        } else if (st >= 13 and (st % 2) == 1) {
-                            const str_result = record.readString(record_data[body_pos..], st);
-                            try stdout.print("{s}", .{str_result.value});
-                        }
-                    }
-                    try stdout.print("\n", .{});
-                    return;
-                }
-            }
-            // Not found in this leaf, stop searching
-            return;
-        } else if (page_type == 0x05) {
-            // Interior table page - use binary search to find the right child
-            const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
-            const rightmost_ptr = std.mem.readInt(u32, page_data[8..12], .big);
-
-            // Find which child to follow based on rowid
-            var next_page: u32 = rightmost_ptr;
-            for (0..num_cells) |i| {
-                const offset = 12 + i * 2;
-                if (offset + 2 > page_data.len) continue;
-                const cell_bytes: *const [2]u8 = page_data[offset .. offset + 2][0..2];
-                const cell_ptr = std.mem.readInt(u16, cell_bytes, .big);
-                if (cell_ptr + 4 > page_data.len) continue;
-
-                const cell_data = page_data[cell_ptr..];
-                const left_child_page = std.mem.readInt(u32, cell_data[0..4], .big);
-
-                const parsed_key = varint.parse(cell_data[4..]);
-                const cell_rowid = parsed_key.value;
-
-                if (target_rowid < cell_rowid) {
-                    next_page = left_child_page;
-                    break;
-                }
-            }
-
-            current_page = next_page;
-        } else {
-            return;
-        }
-    }
-}
-
-inline fn serialTypeSize(st: u64) usize {
-    if (st == 0 or st == 8 or st == 9) {
-        return 0;
-    } else if (st >= 13 and (st % 2) == 1) {
-        return (st - 13) / 2;
-    } else if (st >= 12 and (st % 2) == 0) {
-        return (st - 12) / 2;
-    } else if (st >= 1 and st <= 6) {
-        return @as(usize, st);
-    } else if (st == 7) {
-        return 8;
-    }
-    return 0;
-}
-
-fn readLeafPageRows(page_data: []const u8, column_indices: []const usize, where_column_idx: ?usize, where_value: ?[]const u8, stdout: anytype) !void {
-    const page_type = page_data[0];
-    if (page_type != 0x0d) return;
-
-    const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
-    if (num_cells == 0) return;
-
-    for (0..num_cells) |i| {
-        const offset = 8 + i * 2;
-        if (offset + 2 > page_data.len) continue;
-        const cell_ptr = std.mem.readInt(u16, page_data[offset..][0..2], .big);
-        if (cell_ptr >= page_data.len) continue;
-
-        const cell_data = page_data[cell_ptr..];
-
-        var parsed = varint.parse(cell_data);
-        var pos = parsed.len;
-        if (pos >= cell_data.len) continue;
-
-        parsed = varint.parse(cell_data[pos..]);
-        const rowid = parsed.value;
-        pos += parsed.len;
-        if (pos >= cell_data.len) continue;
-
-        const record_data = cell_data[pos..];
-        parsed = varint.parse(record_data);
-        const header_size = parsed.value;
-        if (header_size > record_data.len or header_size == 0) continue;
-        var header_pos = parsed.len;
-
-        // Parse serial types
-        var serial_types: [256]u64 = undefined;
-        var num_columns: usize = 0;
-        while (header_pos < header_size and num_columns < 256) {
-            parsed = varint.parse(record_data[header_pos..]);
-            serial_types[num_columns] = parsed.value;
-            num_columns += 1;
-            header_pos += parsed.len;
-        }
-
-        // Check WHERE clause if present (early rejection)
-        if (where_column_idx) |where_idx| {
-            if (where_value) |expected_value| {
-                if (where_idx >= num_columns) continue;
-
-                const st = serial_types[where_idx];
-                
-                // Fast path: check serial type first
-                if (st >= 13 and (st % 2) == 1) {
-                    // String comparison - check length first for early rejection
-                    const expected_len = (st - 13) / 2;
-                    if (expected_len != expected_value.len) continue;
-                    
-                    var where_body_pos: usize = header_size;
-                    for (0..where_idx) |col| {
-                        where_body_pos += serialTypeSize(serial_types[col]);
-                    }
-                    
-                    const str_result = record.readString(record_data[where_body_pos..], st);
-                    if (!std.mem.eql(u8, str_result.value, expected_value)) continue;
-                } else if (st >= 1 and st <= 6) {
-                    var where_body_pos: usize = header_size;
-                    for (0..where_idx) |col| {
-                        where_body_pos += serialTypeSize(serial_types[col]);
-                    }
-                    const int_result = record.readInt(record_data[where_body_pos..], st);
-                    const expected_int = std.fmt.parseInt(i64, expected_value, 10) catch 0;
-                    if (int_result.value != expected_int) continue;
-                } else {
-                    continue; // Unsupported type for WHERE
-                }
-            }
-        }
-
-        // Print matching row
-        for (column_indices, 0..) |column_idx, col_num| {
-            if (col_num > 0) try stdout.print("|", .{});
-            if (column_idx >= num_columns) continue;
-
-            var body_pos: usize = header_size;
-            for (0..column_idx) |col| {
-                body_pos += serialTypeSize(serial_types[col]);
-            }
-
-            const st = serial_types[column_idx];
-            if (st == 0) {
-                try stdout.print("{}", .{rowid});
-            } else if (st == 8) {
-                try stdout.print("0", .{});
-            } else if (st == 9) {
-                try stdout.print("1", .{});
-            } else if (st >= 1 and st <= 6) {
-                const int_result = record.readInt(record_data[body_pos..], st);
-                try stdout.print("{}", .{int_result.value});
-            } else if (st >= 13 and (st % 2) == 1) {
-                const str_result = record.readString(record_data[body_pos..], st);
-                try stdout.print("{s}", .{str_result.value});
-            }
-        }
-        try stdout.print("\n", .{});
-    }
-}
-
-fn traverseBTree(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, page_num: u32, column_indices: []const usize, where_column_idx: ?usize, where_value: ?[]const u8, stdout: anytype) !void {
-    // Read entire file into memory for fast random access
-    const file_size = try file.getEndPos();
-    const file_data = try allocator.alloc(u8, file_size);
-    defer allocator.free(file_data);
-
-    _ = try file.seekTo(0);
-    _ = try file.read(file_data);
-
-    var stack = std.ArrayList(u32){};
-    defer stack.deinit(allocator);
-    try stack.append(allocator, page_num);
-
-    while (stack.items.len > 0) {
-        const current_page = stack.pop() orelse continue;
-
-        const page_offset = (current_page - 1) * @as(usize, page_size);
-        if (page_offset + page_size > file_data.len) continue;
-
-        const page_data = file_data[page_offset .. page_offset + page_size];
-        const page_type = page_data[0];
-
-        if (page_type == 0x0d) {
-            try readLeafPageRows(page_data, column_indices, where_column_idx, where_value, stdout);
-        } else if (page_type == 0x05) {
-            const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
-            const rightmost_ptr = std.mem.readInt(u32, page_data[8..12], .big);
-
-            // Add rightmost first so it's processed last (stack LIFO)
-            if (rightmost_ptr != 0) {
-                try stack.append(allocator, rightmost_ptr);
-            }
-
-            // Add children in reverse order for correct traversal
-            var i = num_cells;
-            while (i > 0) {
-                i -= 1;
-                const offset = 12 + i * 2;
-                if (offset + 2 > page_data.len) continue;
-                const cell_ptr_bytes = page_data[offset .. offset + 2];
-                const cell_ptr = std.mem.readInt(u16, cell_ptr_bytes[0..2], .big);
-                if (cell_ptr + 4 > page_data.len) continue;
-
-                const cell_data = page_data[cell_ptr..];
-                const left_child_page = std.mem.readInt(u32, cell_data[0..4], .big);
-
-                if (left_child_page != 0) {
-                    try stack.append(allocator, left_child_page);
-                }
-            }
-        }
-    }
-}
-
-pub fn getRootpage(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, table_name: []const u8) !u32 {
-    var buf: [2]u8 = undefined;
-    _ = try file.seekTo(103);
-    _ = try file.read(&buf);
-    const num_cells = std.mem.readInt(u16, &buf, .big);
-
-    var cell_pointers = try allocator.alloc(u16, num_cells);
-    defer allocator.free(cell_pointers);
-
-    for (0..num_cells) |i| {
-        _ = try file.seekTo(108 + i * 2);
-        _ = try file.read(&buf);
-        cell_pointers[i] = std.mem.readInt(u16, &buf, .big);
-    }
-
-    var page_data = try allocator.alloc(u8, page_size);
-    defer allocator.free(page_data);
-
-    _ = try file.seekTo(0);
-    _ = try file.read(page_data);
-
-    for (0..num_cells) |i| {
-        const cell_data = page_data[cell_pointers[i]..];
-
-        var parsed = varint.parse(cell_data);
-        var pos = parsed.len;
-
-        parsed = varint.parse(cell_data[pos..]);
-        pos += parsed.len;
-
-        const record_data = cell_data[pos..];
-        parsed = varint.parse(record_data);
-        const header_size = parsed.value;
-        var header_pos = parsed.len;
-
-        var serial_types: [5]u64 = undefined;
-        for (0..5) |col| {
-            parsed = varint.parse(record_data[header_pos..]);
-            serial_types[col] = parsed.value;
-            header_pos += parsed.len;
-        }
+        const type_st = serial_types[0];
+        const name_st = serial_types[1];
+        const rootpage_st = serial_types[3];
 
         var body_pos: usize = header_size;
+        const type_result = record.readString(record_data[body_pos..], type_st);
+        if (!std.mem.eql(u8, type_result.value, "table")) continue;
 
-        const st0 = serial_types[0];
-        if (st0 >= 13 and (st0 % 2) == 1) {
-            body_pos += (st0 - 13) / 2;
-        } else if (st0 >= 1 and st0 <= 6) {
-            const r0 = record.readInt(record_data[body_pos..], st0);
-            body_pos += r0.len;
-        }
-
-        const st1 = serial_types[1];
-        if (st1 >= 13 and (st1 % 2) == 1) {
-            body_pos += (st1 - 13) / 2;
-        } else if (st1 >= 1 and st1 <= 6) {
-            const r1 = record.readInt(record_data[body_pos..], st1);
-            body_pos += r1.len;
-        }
-
-        const tbl_name_result = record.readString(record_data[body_pos..], serial_types[2]);
-        body_pos += tbl_name_result.len;
-
-        if (std.mem.eql(u8, tbl_name_result.value, table_name)) {
-            const rp = record.readInt(record_data[body_pos..], serial_types[3]);
-            return @as(u32, @intCast(rp.value));
-        }
-    }
-
-    return 0;
-}
-
-pub fn countRows(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, rootpage: u32) !u64 {
-    if (rootpage == 0) return 0;
-
-    const page_offset = (rootpage - 1) * @as(u64, page_size);
-    var page_data = try allocator.alloc(u8, page_size);
-    defer allocator.free(page_data);
+        body_pos += type_result.len;
+        const name_result = record.readString(record_data[body_pos..], name_st);
+        if (!std.mem.eql(u8, name_result.value, table_name)) continue;
 
-    _ = try file.seekTo(page_offset);
-    _ = try file.read(page_data);
+        body_pos += name_result.len;
+        body_pos += (serial_types[2] - 13) / 2;
 
-    const page_type = page_data[0];
-    if (page_type == 0x05 or page_type == 0x0d) {
-        return std.mem.readInt(u16, page_data[3..5], .big);
+        const rootpage_result = record.readInt(record_data[body_pos..], rootpage_st);
+        return @as(u32, @intCast(rootpage_result.value));
     }
 
-    return 0;
+    return error.TableNotFound;
 }
 
+/// Get CREATE TABLE SQL for a table
 pub fn getCreateTableSQL(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, table_name: []const u8) ![]const u8 {
     var buf: [2]u8 = undefined;
     _ = try file.seekTo(103);
@@ -609,276 +95,112 @@ pub fn getCreateTableSQL(allocator: std.mem.Allocator, file: *std.fs.File, page_
     _ = try file.read(page_data);
 
     for (0..num_cells) |i| {
+        if (cell_pointers[i] >= page_data.len) continue;
         const cell_data = page_data[cell_pointers[i]..];
 
         var parsed = varint.parse(cell_data);
         var pos = parsed.len;
+        if (pos >= cell_data.len) continue;
 
         parsed = varint.parse(cell_data[pos..]);
         pos += parsed.len;
+        if (pos >= cell_data.len) continue;
 
         const record_data = cell_data[pos..];
         parsed = varint.parse(record_data);
         const header_size = parsed.value;
+        if (header_size > record_data.len) continue;
         var header_pos = parsed.len;
 
         var serial_types: [5]u64 = undefined;
         for (0..5) |col| {
+            if (header_pos >= header_size) break;
             parsed = varint.parse(record_data[header_pos..]);
             serial_types[col] = parsed.value;
             header_pos += parsed.len;
         }
 
-        var body_pos: usize = header_size;
+        const type_st = serial_types[0];
+        const name_st = serial_types[1];
+        const sql_st = serial_types[4];
 
-        const st0 = serial_types[0];
-        if (st0 >= 13 and (st0 % 2) == 1) {
-            body_pos += (st0 - 13) / 2;
-        } else if (st0 >= 1 and st0 <= 6) {
-            const r0 = record.readInt(record_data[body_pos..], st0);
-            body_pos += r0.len;
-        }
+        var body_pos: usize = header_size;
+        const type_result = record.readString(record_data[body_pos..], type_st);
+        if (!std.mem.eql(u8, type_result.value, "table")) continue;
 
-        const st1 = serial_types[1];
-        if (st1 >= 13 and (st1 % 2) == 1) {
-            body_pos += (st1 - 13) / 2;
-        } else if (st1 >= 1 and st1 <= 6) {
-            const r1 = record.readInt(record_data[body_pos..], st1);
-            body_pos += r1.len;
-        }
+        body_pos += type_result.len;
+        const name_result = record.readString(record_data[body_pos..], name_st);
+        if (!std.mem.eql(u8, name_result.value, table_name)) continue;
 
-        const tbl_name_result = record.readString(record_data[body_pos..], serial_types[2]);
-        body_pos += tbl_name_result.len;
+        body_pos += name_result.len;
+        body_pos += (serial_types[2] - 13) / 2;
 
-        if (std.mem.eql(u8, tbl_name_result.value, table_name)) {
-            const rp = record.readInt(record_data[body_pos..], serial_types[3]);
-            body_pos += rp.len;
+        const rootpage_result = record.readInt(record_data[body_pos..], serial_types[3]);
+        body_pos += rootpage_result.len;
 
-            const sql_result = record.readString(record_data[body_pos..], serial_types[4]);
-            return try allocator.dupe(u8, sql_result.value);
-        }
+        const sql_result = record.readString(record_data[body_pos..], sql_st);
+        return try allocator.dupe(u8, sql_result.value);
     }
 
     return error.TableNotFound;
 }
 
+/// Parse column index from CREATE TABLE SQL
 pub fn parseColumnIndex(sql: []const u8, column_name: []const u8) !usize {
-    var paren_idx: ?usize = null;
+    var in_parens = false;
+    var paren_start: usize = 0;
+
     for (sql, 0..) |c, i| {
         if (c == '(') {
-            paren_idx = i;
-            break;
-        }
-    }
-
-    if (paren_idx == null) return error.InvalidSQL;
+            if (!in_parens) {
+                paren_start = i + 1;
+                in_parens = true;
+            }
+        } else if (c == ')') {
+            if (in_parens) {
+                const columns_part = sql[paren_start..i];
+
+                var column_idx: usize = 0;
+                var start: usize = 0;
+                var in_col = false;
+
+                for (columns_part, 0..) |ch, j| {
+                    if (!in_col) {
+                        if (ch != ' ' and ch != '\t' and ch != '\n' and ch != '\r') {
+                            start = j;
+                            in_col = true;
+                        }
+                    } else {
+                        if (ch == ',' or j == columns_part.len - 1) {
+                            var end = j;
+                            if (j == columns_part.len - 1 and ch != ',') {
+                                end = j + 1;
+                            }
 
-    var col_idx: usize = 0;
-    var in_col_name = false;
-    var col_start: usize = paren_idx.? + 1;
+                            const col_def = columns_part[start..end];
 
-    for (sql[paren_idx.? + 1 ..], 0..) |c, i| {
-        const actual_idx = paren_idx.? + 1 + i;
+                            var space_idx: usize = 0;
+                            for (col_def, 0..) |col_ch, col_i| {
+                                if (col_ch == ' ' or col_ch == '\t') {
+                                    space_idx = col_i;
+                                    break;
+                                }
+                            }
 
-        if (c == ')') break;
+                            const col_name = if (space_idx > 0) col_def[0..space_idx] else col_def;
 
-        if (c == ' ' or c == '\t' or c == '\n') {
-            if (in_col_name) {
-                const col_name = std.mem.trim(u8, sql[col_start..actual_idx], " \t\n");
-                if (std.mem.eql(u8, col_name, column_name)) {
-                    return col_idx;
-                }
-                in_col_name = false;
-            }
-            continue;
-        }
+                            if (std.mem.eql(u8, col_name, column_name)) {
+                                return column_idx;
+                            }
 
-        if (c == ',') {
-            if (in_col_name) {
-                const col_name = std.mem.trim(u8, sql[col_start..actual_idx], " \t\n");
-                if (std.mem.eql(u8, col_name, column_name)) {
-                    return col_idx;
+                            column_idx += 1;
+                            in_col = false;
+                        }
+                    }
                 }
             }
-            col_idx += 1;
-            in_col_name = false;
-            continue;
-        }
-
-        if (!in_col_name) {
-            col_start = actual_idx;
-            in_col_name = true;
         }
     }
 
     return error.ColumnNotFound;
 }
-
-pub fn readTableRows(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, rootpage: u32, column_idx: usize, stdout: anytype) !void {
-    if (rootpage == 0) return;
-
-    const page_offset = (rootpage - 1) * @as(u64, page_size);
-    var page_data = try allocator.alloc(u8, page_size);
-    defer allocator.free(page_data);
-
-    _ = try file.seekTo(page_offset);
-    _ = try file.read(page_data);
-
-    const page_type = page_data[0];
-    if (page_type != 0x0d) return;
-
-    const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
-
-    var cell_pointers = try allocator.alloc(u16, num_cells);
-    defer allocator.free(cell_pointers);
-
-    for (0..num_cells) |i| {
-        const offset = 8 + i * 2;
-        const cell_ptr_bytes = page_data[offset .. offset + 2];
-        cell_pointers[i] = std.mem.readInt(u16, cell_ptr_bytes[0..2], .big);
-    }
-
-    for (0..num_cells) |i| {
-        const cell_data = page_data[cell_pointers[i]..];
-
-        var parsed = varint.parse(cell_data);
-        var pos = parsed.len;
-
-        parsed = varint.parse(cell_data[pos..]);
-        pos += parsed.len;
-
-        const record_data = cell_data[pos..];
-        parsed = varint.parse(record_data);
-        const header_size = parsed.value;
-        var header_pos = parsed.len;
-
-        var serial_types = std.ArrayList(u64){};
-        defer serial_types.deinit(allocator);
-
-        while (header_pos < header_size) {
-            parsed = varint.parse(record_data[header_pos..]);
-            try serial_types.append(allocator, parsed.value);
-            header_pos += parsed.len;
-        }
-
-        var body_pos: usize = header_size;
-        for (0..column_idx) |col| {
-            if (col >= serial_types.items.len) break;
-            const st = serial_types.items[col];
-            if (st >= 13 and (st % 2) == 1) {
-                body_pos += (st - 13) / 2;
-            } else if (st >= 1 and st <= 6) {
-                const int_result = record.readInt(record_data[body_pos..], st);
-                body_pos += int_result.len;
-            }
-        }
-
-        if (column_idx < serial_types.items.len) {
-            const st = serial_types.items[column_idx];
-            if (st >= 13 and (st % 2) == 1) {
-                const str_result = record.readString(record_data[body_pos..], st);
-                try stdout.print("{s}\n", .{str_result.value});
-            } else if (st >= 1 and st <= 6) {
-                const int_result = record.readInt(record_data[body_pos..], st);
-                try stdout.print("{}\n", .{int_result.value});
-            }
-        }
-    }
-}
-
-pub fn readTableRowsMultiColumn(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, rootpage: u32, column_indices: []const usize, stdout: anytype) !void {
-    if (rootpage == 0) return;
-
-    const page_offset = (rootpage - 1) * @as(u64, page_size);
-    var page_data = try allocator.alloc(u8, page_size);
-    defer allocator.free(page_data);
-
-    _ = try file.seekTo(page_offset);
-    _ = try file.read(page_data);
-
-    const page_type = page_data[0];
-    if (page_type != 0x0d) return;
-
-    const num_cells = std.mem.readInt(u16, page_data[3..5], .big);
-
-    var cell_pointers = try allocator.alloc(u16, num_cells);
-    defer allocator.free(cell_pointers);
-
-    for (0..num_cells) |i| {
-        const offset = 8 + i * 2;
-        const cell_ptr_bytes = page_data[offset .. offset + 2];
-        cell_pointers[i] = std.mem.readInt(u16, cell_ptr_bytes[0..2], .big);
-    }
-
-    for (0..num_cells) |i| {
-        const cell_data = page_data[cell_pointers[i]..];
-
-        var parsed = varint.parse(cell_data);
-        var pos = parsed.len;
-
-        parsed = varint.parse(cell_data[pos..]);
-        pos += parsed.len;
-
-        const record_data = cell_data[pos..];
-        parsed = varint.parse(record_data);
-        const header_size = parsed.value;
-        var header_pos = parsed.len;
-
-        var serial_types = std.ArrayList(u64){};
-        defer serial_types.deinit(allocator);
-
-        while (header_pos < header_size) {
-            parsed = varint.parse(record_data[header_pos..]);
-            try serial_types.append(allocator, parsed.value);
-            header_pos += parsed.len;
-        }
-
-        for (column_indices, 0..) |column_idx, col_num| {
-            var body_pos: usize = header_size;
-            for (0..column_idx) |col| {
-                if (col >= serial_types.items.len) break;
-                const st = serial_types.items[col];
-                if (st >= 13 and (st % 2) == 1) {
-                    body_pos += (st - 13) / 2;
-                } else if (st >= 1 and st <= 6) {
-                    const int_result = record.readInt(record_data[body_pos..], st);
-                    body_pos += int_result.len;
-                }
-            }
-
-            if (col_num > 0) {
-                try stdout.print("|", .{});
-            }
-
-            if (column_idx < serial_types.items.len) {
-                const st = serial_types.items[column_idx];
-                if (st >= 13 and (st % 2) == 1) {
-                    const str_result = record.readString(record_data[body_pos..], st);
-                    try stdout.print("{s}", .{str_result.value});
-                } else if (st >= 1 and st <= 6) {
-                    const int_result = record.readInt(record_data[body_pos..], st);
-                    try stdout.print("{}", .{int_result.value});
-                }
-            }
-        }
-        try stdout.print("\n", .{});
-    }
-}
-
-pub fn readTableRowsMultiColumnWhere(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, rootpage: u32, column_indices: []const usize, where_column_idx: ?usize, where_value: ?[]const u8, stdout: anytype) !void {
-    try traverseBTree(allocator, file, page_size, rootpage, column_indices, where_column_idx, where_value, stdout);
-}
-
-pub fn readTableRowsWithIndex(allocator: std.mem.Allocator, file: *std.fs.File, page_size: u16, table_name: []const u8, table_rootpage: u32, column_indices: []const usize, where_column: []const u8, where_value: []const u8, stdout: anytype) !void {
-    _ = allocator;
-    _ = file;
-    _ = page_size;
-    _ = table_name;
-    _ = table_rootpage;
-    _ = column_indices;
-    _ = where_column;
-    _ = where_value;
-    _ = stdout;
-    // Temporarily disable to test table scan
-    return error.NoIndexFound;
-}