PostgreSQL – TRIGGERS PostgreSQL Triggers are database callback functions, which are automatically performed/invoked when a specified database event occurs. The following are important points about PostgreSQL triggers − PostgreSQL trigger can be specified to fire Before the operation is attempted on a row (before constraints are checked and the INSERT, UPDATE or DELETE is attempted) […]
Category Archives: postgresql
PostgreSQL – INDEXES Indexes are special lookup tables that the database search engine can use to speed up data retrieval. Simply put, an index is a pointer to data in a table. An index in a database is very similar to an index in the back of a book. For example, if you want to […]
PostgreSQL – ALTER TABLE Command The PostgreSQL ALTER TABLE command is used to add, delete or modify columns in an existing table. You would also use ALTER TABLE command to add and drop various constraints on an existing table. Syntax The basic syntax of ALTER TABLE to add a new column in an existing table […]