feat: v0.1.13 — 事务回滚 + 子查询 + 外键级联 + 连接池

src/engine/memory.ts

@@ -16,6 +16,13 @@ export class MemoryEngine implements IStorageEngine {
   private indexes: Map<string, Map<string, Map<unknown, Set<string>>>> = new Map();
   private opened = false;
 
+  // ---- 事务快照 ----
+  private snapshot: {
+    tables: Map<string, Map<string, Record<string, unknown>>>;
+    schemas: Map<string, TableSchema>;
+    indexes: Map<string, Map<string, Map<unknown, Set<string>>>>;
+  } | null = null;
+
   // ---- 生命周期 ----
   async open(_dbName: string, _version: number): Promise<void> { this.opened = true; }
   async close(): Promise<void> {
@@ -109,8 +116,14 @@ export class MemoryEngine implements IStorageEngine {
         toDelete.push(pk);
       }
     }
+    // 级联删除：检查引用此表的其他表
+    let cascadeCount = 0;
+    for (const pk of toDelete) {
+      const row = table.get(pk);
+      if (row) cascadeCount += await this.cascadeDelete(tableName, pk, row);
+    }
     for (const pk of toDelete) table.delete(pk);
-    return toDelete.length;
+    return toDelete.length + cascadeCount;
   }
 
   async count(tableName: string, query?: QueryPlan): Promise<number> {
@@ -129,6 +142,56 @@ export class MemoryEngine implements IStorageEngine {
     if (tableIndexes) for (const colIndex of tableIndexes.values()) colIndex.clear();
   }
 
+  // ---- 事务 ----
+
+  async beginTransaction(): Promise<void> {
+    if (this.snapshot) throw new DatabaseError('Transaction already in progress', 'TX_ACTIVE');
+    this.snapshot = {
+      tables: this.deepCloneMapMap(this.tables),
+      schemas: new Map(this.schemas),
+      indexes: this.deepCloneIndexes(this.indexes),
+    };
+  }
+
+  async commitTransaction(): Promise<void> {
+    if (!this.snapshot) throw new DatabaseError('No active transaction', 'TX_NONE');
+    this.snapshot = null;
+  }
+
+  async rollbackTransaction(): Promise<void> {
+    if (!this.snapshot) throw new DatabaseError('No active transaction', 'TX_NONE');
+    this.tables = this.snapshot.tables;
+    this.schemas = this.snapshot.schemas;
+    this.indexes = this.snapshot.indexes;
+    this.snapshot = null;
+  }
+
+  // ---- 事务快照辅助 ----
+
+  private deepCloneMapMap(source: Map<string, Map<string, Record<string, unknown>>>): Map<string, Map<string, Record<string, unknown>>> {
+    const clone = new Map<string, Map<string, Record<string, unknown>>>();
+    for (const [k, v] of source) {
+      const innerClone = new Map<string, Record<string, unknown>>();
+      for (const [ik, iv] of v) innerClone.set(ik, { ...iv });
+      clone.set(k, innerClone);
+    }
+    return clone;
+  }
+
+  private deepCloneIndexes(source: Map<string, Map<string, Map<unknown, Set<string>>>>): Map<string, Map<string, Map<unknown, Set<string>>>> {
+    const clone = new Map<string, Map<string, Map<unknown, Set<string>>>>();
+    for (const [tableName, tableIndexes] of source) {
+      const tableClone = new Map<string, Map<unknown, Set<string>>>();
+      for (const [col, colIndex] of tableIndexes) {
+        const colClone = new Map<unknown, Set<string>>();
+        for (const [val, pkSet] of colIndex) colClone.set(val, new Set(pkSet));
+        tableClone.set(col, colClone);
+      }
+      clone.set(tableName, tableClone);
+    }
+    return clone;
+  }
+
   // ---- 内部辅助 ----
   private ensureTable(tableName: string): void {
     if (!this.tables.has(tableName)) throw new DatabaseError(`Table "${tableName}" does not exist`, 'TABLE_NOT_FOUND');
@@ -212,4 +275,58 @@ export class MemoryEngine implements IStorageEngine {
       }
     }
   }
+
+  // ---- 外键级联 ----
+
+  /**
+   * 级联删除：查找引用 tableName.pkValue 的所有表的行并删除。
+   * @returns 级联删除的行数
+   */
+  private async cascadeDelete(tableName: string, pkValue: string, _row: Record<string, unknown>): Promise<number> {
+    let totalCascade = 0;
+
+    for (const [refTableName, refSchema] of this.schemas) {
+      if (refTableName === tableName) continue;
+
+      for (const [colName, colDef] of Object.entries(refSchema.columns)) {
+        if (!colDef.references || !colDef.onDelete || colDef.onDelete === 'RESTRICT') continue;
+
+        const [refTable, refCol] = colDef.references.split('.');
+        if (refTable !== tableName) continue;
+
+        const refPkCol = refCol;
+        const refTableData = this.tables.get(refTableName);
+        if (!refTableData) continue;
+
+        // 查找所有引用此主键的行
+        const toDelete: string[] = [];
+        for (const [refPk, refRow] of refTableData) {
+          if (String(refRow[colName]) === pkValue) {
+            toDelete.push(refPk);
+          }
+        }
+
+        if (colDef.onDelete === 'CASCADE') {
+          // 递归级联
+          for (const refPk of toDelete) {
+            const refRow = refTableData.get(refPk);
+            if (refRow) {
+              totalCascade += await this.cascadeDelete(refTableName, refPk, refRow);
+            }
+            refTableData.delete(refPk);
+            totalCascade++;
+          }
+        } else if (colDef.onDelete === 'SET NULL') {
+          for (const refPk of toDelete) {
+            const refRow = refTableData.get(refPk);
+            if (refRow) {
+              refRow[colName] = null;
+            }
+          }
+        }
+      }
+    }
+
+    return totalCascade;
+  }
 }