Languages#

What Are “Languages” in PostgreSQL?#

In PostgreSQL, Languages means:

Programming languages that PostgreSQL can use to write stored procedures, functions, triggers, and event triggers.

PostgreSQL is not just SQL — it can execute code written in other languages inside the database.

1️ Why Does PostgreSQL Need Languages?#

SQL alone is not enough for:

Loops
Conditions (if, else)
Error handling
Complex logic
Automation
Validation
System rules

So PostgreSQL embeds procedural languages.

2️ What Is plpgsql?#

plpgsql stands for:

Procedural Language PostgreSQL

It is:

PostgreSQL’s native programming language
Installed by default
Tightly integrated with SQL

That’s why you see Languages (1) → plpgsql

3️ What Can You Do With plpgsql?#

With plpgsql, you can create:

Functions
Stored procedures
Triggers
Event triggers
Business rules
Auditing logic
Security checks

4️ Simple plpgsql Example#

CREATE OR REPLACE FUNCTION add_numbers(a INT, b INT)
RETURNS INT
LANGUAGE plpgsql
AS $$
BEGIN
    RETURN a + b;
END;
$$;

Call it:

SELECT add_numbers(5, 3);

5️ plpgsql vs SQL#

Feature	SQL	plpgsql
Simple queries	✅	❌
Loops	❌	✅
IF / ELSE	❌	✅
Variables	❌	✅
Error handling	❌	✅
Triggers	❌	✅

plpgsql wraps SQL inside logic

6️ Why pgAdmin Shows “Languages” Under a Database#

Languages are:

Database-level objects
Installed per database
Stored in system catalogs

So each database can have:

Different languages
Different permissions

7️ Other PostgreSQL Languages (Optional)#

PostgreSQL supports many languages via extensions:

Language	Name
PL/pgSQL	plpgsql
Python	plpython3u
JavaScript	plv8
Perl	plperl
Tcl	pltcl
R	plr

Example:

CREATE EXTENSION plpython3u;

Then it appears under Languages.

8️ Trusted vs Untrusted Languages#

Type	Meaning
Trusted	Safe, sandboxed
Untrusted (u)	Can access OS

Examples:

plpgsql → trusted
plpython3u → untrusted

That’s why superuser privileges are required.

9️ Languages vs Extensions#

Languages	Extensions
Execution engine	Feature bundle
Used for logic	Used for capabilities
Required for triggers	May add languages
plpgsql is default	postgis, pgcrypto

Some extensions add languages.

Note

PostgreSQL Languages are procedural programming languages that allow developers to write functions, stored procedures, and triggers inside the database. The default language, plpgsql, enables complex logic, loops, conditions, and error handling beyond standard SQL.