Postgres and Open Source Experts

In PostgreSQL, the “\df” mata-command, “information_schema.routines” View, and the “pg_proc” Catalog is used to get the list of user-defined functions.

The CREATE FUNCTION statement allows us to create a user-defined function by specifying its name, parameters, return type, and the language to be implemented.

To update a Postgres table using Python, first, create a Python file, import the “psycopg2” library, make a connection between Postgres and Python, and update table.

To create a Postgres table using Python, first, create a Python file, import the “psycopg2” library, establish the connection between Postgres and Python, and create a table.

To remove/delete a password for a user in Postgres, execute the “ALTER USER user_name PASSWORD NULL;” command. Replace user_name with the username of your choice.

UPDATE JOIN in PostgreSQL is used to alter the values of the tables using the reference of the other table having a common column available in both tables.

A database transaction in PostgreSQL is used to perform multiple steps at once and confirm it using the COMMIT clause or reverse it with the ROLLBACK keyword.

NATURAL JOIN supports INNER, LEFT, and RIGHT JOINs but uses INNER by default as it is used to combine multiple tables having the same field names.

FULL OUTER JOIN combines the working of both LEFT and RIGHT JOINs to produce a result table containing matched and unmatched results from the tables.

DELETE JOIN is not directly supported by the PostgreSQL database but a DELETE statement with either USING or WHERE clauses can be used for this purpose.