Transactions::SavePoints

Savepoints

Savepoints provide finer-grained control of transactions by marking intermediate points within a transaction. Once a savepoint has been set, the transaction can be rolled back to that savepoint without affecting preceding work. The DatabaseMetaData.supportsSavepoints method can be used to determine whether a JDBC driver and DBMS support savepoints.

Setting and Rolling Back to a Savepoint

The JDBC 3.0 API adds the method Connection.setSavepoint, which sets a savepoint within the current transaction. The Connection.rollback method has been overloaded to take a savepoint argument.

CODE EXAMPLE inserts a row into a table, sets the savepoint svpt1, and then inserts a second row. When the transaction is later rolled back to svpt1, the second insertion is undone, but the first insertion remains intact. In other words, when the transaction is committed, only the row containing ’FIRST’ will be added to TAB1.

conn.createStatement();
int rows = stmt.executeUpdate("INSERT INTO TAB1 (COL1) VALUES " +
"(’FIRST’)");
// set savepoint
Savepoint svpt1 = conn.setSavepoint("SAVEPOINT_1");
rows = stmt.executeUpdate("INSERT INTO TAB1 (COL1) " +
"VALUES (’SECOND’)");
...
conn.rollback(svpt1);
...
conn.commit();

CODE EXAMPLE Rolling back a transaction to a savepoint

Releasing a Savepoint

The method Connection.releaseSavepoint takes a Savepoint object as a parameter and removes it from the current transaction. Once a savepoint has been released, attempting to reference it in a rollback operation will cause an SQLException to be thrown. Any savepoints that have been created in a transaction are automatically released and become invalid when the transaction is committed or when the entire transaction is rolled back. Rolling a transaction back to a savepoint automatically releases and makes invalid any other savepoints that were created after the savepoint in question