2F002ERRORTier 2 — Caution✅ HIGH confidence

modifying SQL data not permitted

Category: SQL Routine ExceptionVersions: All Postgres versions

What this means

SQLSTATE 2F002 is raised when a SQL function declared as CONTAINS SQL or READS SQL DATA attempts to modify data (INSERT, UPDATE, DELETE), which is not permitted by its declared data access category.

Why it happens

1A SQL function with CONTAINS SQL or READS SQL DATA attribute attempts to execute a DML statement that modifies data

How to reproduce

SQL function with READS SQL DATA attempting a write.

trigger — this will ERROR

CREATE FUNCTION read_only_fn() RETURNS VOID
LANGUAGE SQL
READS SQL DATA
AS $ INSERT INTO log (msg) VALUES ('test'); $; -- modifies data

ERROR: modifying SQL-data not permitted

Fix 1: Change the function to MODIFIES SQL DATA if data modification is intentional

When the function should be allowed to write data.

fix

CREATE OR REPLACE FUNCTION my_fn() RETURNS VOID
LANGUAGE SQL
MODIFIES SQL DATA
AS $ INSERT INTO log (msg) VALUES ('test'); $;

Why this works

MODIFIES SQL DATA declares that the function may change data, allowing DML statements.

Sources

📚 Official docs: https://www.postgresql.org/docs/current/errcodes-appendix.html

🔧 Source ref: Class 2F — SQL Routine Exception

Confidence assessment

✅ HIGH confidence

Standard SQLSTATE. Stable across versions.