Experts in Postgres and Open Source Infrastructure

regexp_matches() function takes in the string and the regular expression to be matched as an argument along with an optional flag and returns the first matched substring from the main string.

In Postgresql, the regexp_split_to_array() function is used to split the specified string into an array using the specified POSIX regular expressions

The make_date () function takes arguments, then creates and returns a date with them. The make_time() function takes arguments, then creates and returns a time without a time zone.

Array_position() function gives the first occurrence of an element while the Array_positions() function gives all the occurrences of an element in an array.

To enable a trigger in PostgreSQL, the “ALTER TABLE” statement is used with the “DISABLE TRIGGER” clause. We need to specify the name of the trigger associated with a particular table in case of enabling one trigger.

In PostgreSQL, different methods are used to list all the triggers associated with a database, such as "pg_trigger catalog", "psql" command, and SQL queries.

In PostgreSQL, a trigger can be dropped from the table by specifying the name of the trigger and the name of the table to which it is associated.

In PostgreSQL, the "ALTER TABLE" with the "DISABLE TRIGGER" clause is used to disable a trigger. We need to specify the name of the trigger associated with a particular table in case of disabling one trigger.

In PostgreSQL, we use the make_timestamp() and make_timestamptz() functions to show the timestamps. Both functions give errors when the input parameters have some issue maybe due to the wrong data type, etc.

Triggers are useful in many ways such as keeping an audit for changes and transactions, applying the business rules, and validating the user input data.