PostgreSQL Error - 23000 integrity_constraint_violation Error Explained

What is the integrity_constraint_violation error?

integrity_constraint_violation is PostgreSQL’s SQLSTATE class 23000. The server raises it when a data modification violates a table’s integrity rule, such as primary key, foreign key, unique, check, or NOT NULL constraints.

The error stops the current statement and rolls it back unless it is inside a savepoint or deferrable transaction.

Fixing it quickly is critical because repeated violations can block application workflows and corrupt business logic.

What Causes This Error?

The error fires when incoming data conflicts with an existing constraint definition. Duplicate primary keys, orphaned foreign keys, or values outside a CHECK range are typical triggers. PostgreSQL validates constraints before writing to disk, so violations surface immediately.

Mis-ordered inserts during bulk loads, missing default values, and race conditions in concurrent sessions also cause 23000 errors.

Applications that construct SQL dynamically without validation are especially vulnerable.

How to Fix integrity_constraint_violation

First, read the full server message; PostgreSQL usually appends a more specific code like 23505 (duplicate key) or 23503 (foreign key). That detail points to the exact constraint you must address.

Next, locate the constraint with \d table_name or pg_constraint. Compare the failing row to existing data. Update offending values, delete bad rows, or change the operation to INSERT ...

ON CONFLICT to handle duplicates gracefully.

Common Scenarios and Solutions

Duplicate key on insert: Use a sequence or UUID generator to guarantee unique primary keys, or switch to ON CONFLICT DO NOTHING when idempotence is acceptable.

Missing parent row: Insert into the parent table first, or defer the foreign key constraint with DEFERRABLE INITIALLY DEFERRED inside a transaction.

CHECK failure: Relax the CHECK expression if business rules changed, or correct the data before retrying.

Best Practices to Avoid This Error

Always insert parent rows before child rows, wrap multi-table writes in a transaction, and validate data types and ranges in your application layer.

Use Galaxy’s AI copilot to review generated SQL for potential constraint clashes and run queries in a sandbox before promoting them to production.

Related Errors and Solutions

SQLSTATE 23505 duplicate key provides the exact constraint name for primary or unique violations.

SQLSTATE 23503 signals a foreign key issue. SQLSTATE 23514 covers CHECK failures. Handling them follows the same locate-and-fix pattern described above.

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