SQLSTATE 23000 ERROR Class 23: Integrity Constraint Violation

integrity_constraint_violation Integrity Constraint Violation — SQLSTATE 23000

SQLSTATE 23000 (integrity_constraint_violation): A write violates a NOT NULL, UNIQUE, CHECK, or FOREIGN KEY constraint.

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Last reviewed May 2025 Grounded in source

Symptoms

The server reports SQLSTATE 23000 (integrity_constraint_violation), a condition in the Integrity Constraint Violation class.

  • The error is written to the server log and returned to the client carrying SQLSTATE 23000.
  • Any driver (libpq, JDBC, psycopg, npgsql, pgx) surfaces this code in its error object so you can branch on it programmatically.
  • PL/pgSQL can trap it by name: EXCEPTION WHEN integrity_constraint_violation THEN.

Environment

Severity: ERROR  |  PostgreSQL versions: 12, 13, 14, 15, 16, 17

Reproduce with the exact statement and read the full message in the server log (raise log_min_messages / set log_min_error_statement for more context).

Root Cause

23000 belongs to Class 23 — Integrity Constraint Violation. In this class, a write violates a NOT NULL, UNIQUE, CHECK, or FOREIGN KEY constraint.

The first two characters (23) identify the error class, so application code can match the whole class via 23000 when the specific code is not needed.

Diagnostic Queries

Recovery

Identify the named constraint from the error detail, then fix the data: supply required values, deduplicate or use ON CONFLICT, insert parent rows before children, and satisfy CHECK expressions.

Reference: PostgreSQL error codes — Class 23 (Integrity Constraint Violation).

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