[fix] 多次调用 Open() 错误

db.go

@@ -17,21 +17,19 @@ func (d *DB) SetLogger(f func(log Log)) *DB {
 }
 
 func Open(config map[string]DBConfig) *DB {
-	var configP = make(map[string]*DBConfig)
+	if Engine == nil {
-
+		Engine = &DB{
-	for name := range config {
-		c := config[name]
-		configP[name] = &c
-	}
-
-	db := DB{
 			DatabaseManager: DatabaseManager{
-			Configs:     configP,
+				Configs:     make(map[string]*DBConfig),
 				Connections: make(map[string]*Connection),
 			},
 		}
+	}
 
-	Engine = &db
+	for name := range config {
+		c := config[name]
+		Engine.Configs[name] = &c
+	}
 
 	return Engine
 }