Initial commit: SRDB - High-performance LSM-Tree database

- Core engine with MemTable, SST, WAL
- B+Tree indexing for SST files  
- Leveled compaction strategy
- Multi-table database management
- Schema validation and secondary indexes
- Query builder with complex conditions
- Web UI with HTMX for data visualization
- Command-line tools for diagnostics

table.go

@@ -0,0 +1,143 @@
+package srdb
+
+import (
+	"os"
+	"path/filepath"
+	"time"
+
+	"code.tczkiot.com/srdb/sst"
+)
+
+// Table 表
+type Table struct {
+	name      string    // 表名
+	dir       string    // 表目录
+	schema    *Schema   // Schema
+	engine    *Engine   // Engine 实例
+	database  *Database // 所属数据库
+	createdAt int64     // 创建时间
+}
+
+// createTable 创建新表
+func createTable(name string, schema *Schema, db *Database) (*Table, error) {
+	// 创建表目录
+	tableDir := filepath.Join(db.dir, name)
+	err := os.MkdirAll(tableDir, 0755)
+	if err != nil {
+		os.RemoveAll(tableDir)
+		return nil, err
+	}
+
+	// 创建 Engine（Engine 会自动保存 Schema 到文件）
+	engine, err := OpenEngine(&EngineOptions{
+		Dir:          tableDir,
+		MemTableSize: DefaultMemTableSize,
+		Schema:       schema,
+	})
+	if err != nil {
+		os.RemoveAll(tableDir)
+		return nil, err
+	}
+
+	table := &Table{
+		name:      name,
+		dir:       tableDir,
+		schema:    schema,
+		engine:    engine,
+		database:  db,
+		createdAt: time.Now().Unix(),
+	}
+
+	return table, nil
+}
+
+// openTable 打开已存在的表
+func openTable(name string, db *Database) (*Table, error) {
+	tableDir := filepath.Join(db.dir, name)
+
+	// 打开 Engine（Engine 会自动从 schema.json 恢复 Schema）
+	eng, err := OpenEngine(&EngineOptions{
+		Dir:          tableDir,
+		MemTableSize: DefaultMemTableSize,
+		// Schema 不设置，让 Engine 自动从磁盘恢复
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	// 从 Engine 获取 Schema
+	sch := eng.GetSchema()
+
+	table := &Table{
+		name:     name,
+		dir:      tableDir,
+		schema:   sch,
+		engine:   eng,
+		database: db,
+	}
+
+	return table, nil
+}
+
+// GetName 获取表名
+func (t *Table) GetName() string {
+	return t.name
+}
+
+// GetSchema 获取 Schema
+func (t *Table) GetSchema() *Schema {
+	return t.schema
+}
+
+// Insert 插入数据
+func (t *Table) Insert(data map[string]any) error {
+	return t.engine.Insert(data)
+}
+
+// Get 查询数据
+func (t *Table) Get(seq int64) (*sst.Row, error) {
+	return t.engine.Get(seq)
+}
+
+// Query 创建查询构建器
+func (t *Table) Query() *QueryBuilder {
+	return t.engine.Query()
+}
+
+// CreateIndex 创建索引
+func (t *Table) CreateIndex(field string) error {
+	return t.engine.CreateIndex(field)
+}
+
+// DropIndex 删除索引
+func (t *Table) DropIndex(field string) error {
+	return t.engine.DropIndex(field)
+}
+
+// ListIndexes 列出所有索引
+func (t *Table) ListIndexes() []string {
+	return t.engine.ListIndexes()
+}
+
+// Stats 获取统计信息
+func (t *Table) Stats() *Stats {
+	return t.engine.Stats()
+}
+
+// GetEngine 获取底层 Engine
+func (t *Table) GetEngine() *Engine {
+	return t.engine
+}
+
+// Close 关闭表
+func (t *Table) Close() error {
+	if t.engine != nil {
+		return t.engine.Close()
+	}
+	return nil
+}
+
+// GetCreatedAt 获取表创建时间
+func (t *Table) GetCreatedAt() int64 {
+	return t.createdAt
+}