Postgres and Open Source Experts

The OVERLAY() function in Postgres replaces some specified characters in the given main string with another specified string.

In PostgreSQL, the regexp_match() function matches a regular expression in a specified main string. This function takes in the string and the regular expression to be matched along with a flag and returns the first matched substring from the main string.

Let’s get into the details of the regexp_match() function.

How Does PostgreSQL regexp_match() Function Do?

The regexp_match() function works almost the same as the regexp_matches() function. It basically returns …

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.

The regexp_split_to_table() function takes the string, the regexp, and the flag(if any) as arguments and returns a table column that contains the string characters with the Regexp as separators.

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.

The array_dims() gives out the information about the dimensions of an array. The array_dims() takes an array as a parameter and returns text that shows array dimensions.

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.