START TRANSACTION

The START TRANSACTION statement is used to begin a transaction.

All statements within a transaction will not be visible to other transactions until all changes are applied with COMMIT or all changes are discarded with ROLLBACK.

Nested transactions are not supported. Attempting to run START TRANSACTION when already in a transaction will result in an error.

Contents

• START TRANSACTION

  • Syntax

  • Implicit Transactions

  • Catalogs

  • Examples

  • See Also

Syntax

START TRANSACTION

Implicit Transactions

When a transaction is not explicitely used, each statement will be automatically wrapped in an implicit transaction. Internally this is important becuase any statements that may make changes (such as a DELETE that removes multiple rows) should seem atomic to all other readers and writers.

Catalogs

Transactions across catalogs are semi-supported. That is, transaction isolation is not guaranteed across catalogs for all operations. And COMMIT and ROLLBACK may independently succeed or fail.

Examples

-- From connection 1:
START TRANSACTION;

INSERT INTO products (name, price)
VALUES ('Coffee Machine', 150);

-- From connection 2:
SELECT * FROM products;
-- empty

-- From connection 1:
COMMIT;

-- From connection 2:
SELECT * FROM products;
-- NAME: Coffee Machine PRICE: 150

See Also

• COMMIT

• ROLLBACK