Question

我正在尝试理解SQLite中的Savepoints和Transactions。我在表/数据库上有以下命令，我正在使用保存点。

SAVEPOINT aaa;
RELEASE aaa;
BEGIN;

现在，如果我一次执行上述所有语句，则会抛出错误A transaction cannot be started inside another transaction。如果我一次运行一个，它运行正常。如果我运行前两个Savepoint并释放命令并尝试通过执行Begin启动另一个事务。它再次抛出与之前相同的错误。

链接fiddle表示

如果在SQLite处于自动提交模式时（即在事务之外）发出SAVEPOINT命令，则将启动标准自动提交BEGIN DEFERRED TRANSACTION。但是，与大多数命令不同，自动提交事务在SAVEPOINT命令返回后不会自动提交，从而使系统处于打开的事务中。自动事务将保持活动状态，直到释放原始保存点，或者外部事务显式提交或回滚。 `

那么，在Release Savepoint命令之后，是否绝对需要Commit或Rollback命令？是不是release命令提交并允许我们使用BEGIN启动新事务？

Answer 1

SAVEPOINT aaa; RELEASE aaa; BEGIN;

由sqlite解释为

BEGIN DEFERRED TRANSACTION; SAVEPOINT aaa; // Create a transaction, and mark current db state as savepoint "aaa" [1] RELEASE aaa; // Remove all db changes made since savepoint "aaa", but keep on executing the transaction BEGIN; // Create another transaction, while there is already a transaction. This will FAIL because there cannot be 2 transactions executed simultaneously

以下情况可以接受：

BEGIN; SAVEPOINT "aaa"; RELEASE "aaa"; COMMIT; BEGIN;

[1] https://sqlite.org/lang_savepoint.html

SQLite中的SAVEPOINT机制

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