Example #4 – Drop trigger in PostgreSQL You can drop a trigger by dropping the “DROP TRIGGER” statement in PostgreSQL. Syntax DROPTRIGGERtrigger_nameontable_name; Example testing=# drop trigger trigger_test on the employee; Output: Conclusion You use the “CREATE TRIGGER” statement to create...
PostgreSQL INSTEAD OF trigger example Let’s take an example of creating anINSTEAD OFtrigger. 1) Setting up a view with an INSTEAD OF trigger First,create two tablesemployeesandsalaries: CREATETABLEemployees(employee_idSERIALPRIMARY KEY,nameVARCHAR(100)NOT NULL);CREATETABLEsalaries(employee_idINT,ef...
A“trigger” is defined as any event that sets a course of action in a motion. In PostgreSQL, if you want to take action on specific database events, such as INSERT, UPDATE, DELETE, or TRUNCATE, then trigger functionality can be useful as it will invoke the required function on defined...
Example: Let’s consider anexamplewhere we want to create a trigger named “update_salary_trigger” that automatically updates the “total_salary” column in the “employees” table whenever an update operation is performed on the “salary” column. ...
Example 2. A PL/pgSQL Trigger Procedure For Auditing This example trigger ensures that any insert, update or delete of a row in the emp table is recorded (i.e., audited) in the emp_audit table. The current time and user name are stamped into the row, together with the type of opera...
PostgreSQL trigger functions are similar to regularuser-defined functions. They are invoked when a particular database event (for example INSERT, UPDATE, DELETE) occurs. Triggers do not take any argument or parameters and return a value having a typetrigger. ...
If we specify a trigger function, we can fix the various trigger events, for example,INSERT,DELETEandUpdate. How to Create a New Trigger We will follow the below process to generate a new trigger in PostgreSQL: Step1:Firstly, we will create a trigger function with the help of theCREATE ...
PostgreSQL provides a very useful event-based trigger system to detect changes to data and automatically perform subsequent tasks. For example, triggers can be used to detect changes on one table and perform related changes on another table; a common form of this usage is a centralized audit ta...
Triggers in PostgreSQL Trigger types The return value of a trigger function NEW and OLD in row level triggers Example an auditing row level trigger Simplification of the row level trigger function Conclusion In this article, I'll talk about row level triggers, which are the most frequently use...
In PostgreSQL, atriggeris a database object that automatically invokes a specifiedfunctionwhen an event occurs on a table or view. These events includeINSERT,UPDATE,DELETE, orTRUNCATE. If atrigger is disabled, it doesn’t activate when the triggering event occurs. To activate the trigger, you’...