Contents
When to use PG _ notify in PSQL trigger function?
Even though I receive a notification when I invoke the pg_notify function from the psql console, I never receive a notification when invoking the same from my trigger function. This version of my trigger function works as expected.
How to create a trigger function in PostgreSQL?
PL/pgSQL can be used to define trigger functions on data changes or database events. A trigger function is created with the CREATE FUNCTION command, declaring it as a function with no arguments and a return type of trigger (for data change triggers) or event_trigger (for database event triggers).
When to use perform instead of PG notify?
ERROR: query has no destination for result data SQL state: 42601 Hint: If you want to discard the results of a SELECT, use PERFORM instead. Changing the SELECT to PERFORM as the error say helps to resolve this issue and the notification gets delivered as expected. Perhaps this could have been the problem.
When to use perform or select in PostgreSQL?
ERROR: query has no destination for result data SQL state: 42601 Hint: If you want to discard the results of a SELECT, use PERFORM instead. Changing the SELECT to PERFORM as the error say helps to resolve this issue and the notification gets delivered as expected.
How to use PG _ notify function in Elixir?
In our procedure, we are calling the pg_notify function inside. accounts_changed is the name of the event to emit, and the contents will be a JSON object like here for example: returned as a text type for the function’s requirements.
When to use listen or notify in PostgreSQL?
It is much easier to use it than the NOTIFY command if you need to work with non-constant channel names and payloads. PostgreSQL allows you to extend the database functionality with user-defined functions, which are often referred to as stored procedures.