Error
Error Code:
40002
PostgreSQL Error 40002: Transaction Integrity Constraint Violation
Description
This error indicates that a database transaction attempted an operation that would violate a defined integrity constraint, such as a PRIMARY KEY, FOREIGN KEY, UNIQUE, CHECK, or NOT NULL constraint. When this occurs, PostgreSQL automatically rolls back the entire transaction to maintain the consistency and integrity of the data.
Error Message
transaction integrity constraint violation
Known Causes
4 known causesDuplicate Key Violation
An attempt was made to insert or update a row with a primary key or unique key value that already exists in the table.
Foreign Key Violation
An operation tried to reference a non-existent value in a parent table, or delete a parent row while dependent child rows still exist.
Check Constraint Violation
Data being inserted or updated does not satisfy a defined CHECK constraint rule for a column or table.
Not Null Constraint Violation
An attempt was made to insert a NULL value into a column that has been defined with a NOT NULL constraint.
Solutions
3 solutions available1. Identify and Correct Constraint Violations medium
Examine your database schema for constraints that are being violated within the transaction.
1
The error 'transaction integrity constraint violation' indicates that a constraint (like UNIQUE, FOREIGN KEY, CHECK, NOT NULL) has been violated during the execution of a transaction. You need to identify which constraint is causing the issue. This often requires analyzing the sequence of operations within the transaction that failed.
2
Review recent changes to your database schema or application code that interacts with the database. Look for new constraints or modifications to existing ones. Pay close attention to tables involved in the failing transaction.
3
If you have logging enabled for your PostgreSQL server, examine the server logs around the time of the error. PostgreSQL often provides more specific details about which constraint was violated and on which table/row.
4
Temporarily disable triggers or constraints if you suspect they are causing the issue and are not critical for data integrity during development or testing. **Caution: This should only be done in non-production environments or with extreme care.**
ALTER TABLE your_table DISABLE TRIGGER trigger_name;
ALTER TABLE your_table DROP CONSTRAINT constraint_name;5
Once the offending constraint is identified, either modify the data being inserted/updated to comply with the constraint, or adjust the constraint definition itself if it's too restrictive or incorrect. For example, if a UNIQUE constraint is violated, ensure you are not inserting duplicate values.
UPDATE your_table SET column_name = 'new_value' WHERE id = some_id;
-- Or, if adjusting the constraint:
ALTER TABLE your_table ALTER COLUMN column_name SET NOT NULL;2. Simplify and Isolate the Transaction medium
Break down complex transactions to pinpoint the exact statement causing the violation.
1
If the error occurs within a large or complex transaction, try to break it down into smaller, more manageable units. Execute parts of the transaction individually to see which segment triggers the 'transaction integrity constraint violation'.
2
Use `BEGIN; ... COMMIT;` or `BEGIN; ... ROLLBACK;` blocks to test smaller portions of your logic. This helps isolate the statement or sequence of statements that violates a constraint.
BEGIN;
-- Execute a subset of your transaction statements here
-- COMMIT; -- or ROLLBACK;3
Once the problematic statement is identified, carefully review the data being operated on and the relevant constraint definitions. Ensure the data conforms to the constraint's rules.
3. Review Application Logic and Data Handling medium
Ensure your application code correctly handles data and adheres to database constraints.
1
The error might stem from the application's logic that prepares and sends data to PostgreSQL. Review the application code that constructs the SQL statements or data being sent.
2
Check for race conditions or concurrency issues in your application. If multiple processes or threads are modifying the same data concurrently, they might interfere with each other and lead to constraint violations.
3
Implement robust data validation in your application layer *before* sending data to the database. This can catch potential constraint violations early, preventing them from reaching the database transaction.
4
If you are using an ORM (Object-Relational Mapper), consult its documentation for how it handles constraint violations and transactions. Ensure your ORM is configured correctly and that you are using its features for data integrity as intended.