PostgreSQL Version 8's Transaction Savepoints Can Save Your Data
While transactions are nice, PostgreSQL's current all-or-nothing transaction mechanism leaves much to be desired when an error occurs within the transaction code. Fortunately, the upcoming PostgreSQL version 8 addresses that problem by adding "savepoints," letting you roll back only part of a transaction and recover from errors gracefully.
by Joshua D. Drake
October 6, 2004
ne much-lauded feature of PostgreSQL is transactions. Transactions in a database help prevent accidental data loss or misrepresentation.
For example, let's say you want to delete records from a table. In PostgreSQL the command is:
template1=# DELETE FROM foo;
However, the above command will delete all of the records in the table. This is probably not what you want, and—unless you were using transactions—the only way to get the data back would be from a backup. Using transactions, getting the data back is simple. The command sequence would be:
BEGIN;
DELETE FROM foo;
DELETE 50
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ne much-lauded feature of PostgreSQL is transactions. Transactions in a database help prevent accidental data loss or misrepresentation.
