Now let's move on to an important feature in any database system: transaction processing.
A transaction is a group of one or more SQL commands treated as a unit. PostgreSQL promises that all commands within a transaction will complete or that none of them will complete. If any command within a transaction does not complete, PostgreSQL will roll back all changes made within the transaction.
PostgreSQL makes use of transactions to ensure database consistency. Transactions are needed to coordinate updates made by two or more concurrent users. Changes made by a transaction are not visible to other users until the transaction is committed. When you commit a transaction, you are telling PostgreSQL that all the changes made within ...