Each 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.
Statement syntax
SurrealQL Syntax
CANCEL [ TRANSACTION ];Example usage
The following query shows example usage of this statement.
/**[test]
[[test.results]]
value = "NONE"
[[test.results]]
error = "The query was not executed due to a cancelled transaction"
[[test.results]]
error = "The query was not executed due to a cancelled transaction"
[[test.results]]
error = "The query was not executed due to a cancelled transaction"
[[test.results]]
error = "The query was not executed due to a cancelled transaction"
[[test.results]]
value = "NONE"
*/
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.
/**[test]
[[test.results]]
value = "NONE"
[[test.results]]
error = "The query was not executed due to a failed transaction"
[[test.results]]
error = "The query was not executed due to a failed transaction"
[[test.results]]
error = "The query was not executed due to a failed transaction"
[[test.results]]
error = "The query was not executed due to a failed transaction"
[[test.results]]
error = "Specify a database to use"
[[test.results]]
error = "Cannot COMMIT: the transaction was aborted due to a prior 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;