CANCEL
statementEach statement within SurrealDB is run within its own transaction. If a set of changes need to be made together, then groups of statements can be run together as a single transaction, either succeeding as a whole, or failing without leaving any residual data modifications. While a transaction will fail if any of its statements encounters an error, the CANCEL
statement can also be used to cancel a transaction manually.
SurrealQL SyntaxCANCEL [ TRANSACTION ];
The following query shows example usage of this statement.
BEGIN TRANSACTION; -- Setup accounts CREATE account:one SET balance = 135605.16; CREATE account:two SET balance = 91031.31; -- Move money UPDATE account:one SET balance += 300.00; UPDATE account:two SET balance -= 300.00; -- Rollback all changes CANCEL TRANSACTION;
CANCEL
is not used to automatically cancel a transaction based on a condition such as inside an IF..ELSE block. Instead, a THROW statement is used. THROW can be followed by any value, usually a string containing context behind the error.
BEGIN TRANSACTION; -- Setup accounts CREATE account:one SET balance = 135605.16; CREATE account:two SET balance = 200.31; -- Move money UPDATE account:one SET balance += 300.00; UPDATE account:two SET balance -= 300.00; IF account:two.balance < 0 { THROW "Not enough funds"; }; COMMIT TRANSACTION;