What causes CHECK_CONSTRAINT_VIOLATION?

Source data contains values outside the range defined by the constraint (e.g., a negative amount in a column constrained to be positive). A data pipeline introduced a NULL value into a column with a NOT NULL constraint expressed as a CHECK. An upstream schema change produced values that no longer conform to the constraint. A new constraint was added to an existing table without validating existing data

How do I fix CHECK_CONSTRAINT_VIOLATION?

Run a SELECT query to find the rows violating the constraint before the write. Filter or transform the source data to remove or fix the offending values. Review the CHECK constraint definition: SHOW TBLPROPERTIES to see all constraints. If the constraint is too strict for legitimate data, consider relaxing it after reviewing with the data owner. If the constraint was recently added, validate existing data before applying it to new writes

Medium severitysql

Power BI Refresh Error:
CHECK_CONSTRAINT_VIOLATION

What does this error mean?

A row being inserted or updated violates a CHECK constraint defined on the Delta table. The write operation was rejected to protect data integrity.

Common causes

1Source data contains values outside the range defined by the constraint (e.g., a negative amount in a column constrained to be positive)
2A data pipeline introduced a NULL value into a column with a NOT NULL constraint expressed as a CHECK
3An upstream schema change produced values that no longer conform to the constraint
4A new constraint was added to an existing table without validating existing data

How to fix it

1Run a SELECT query to find the rows violating the constraint before the write
2Filter or transform the source data to remove or fix the offending values
3Review the CHECK constraint definition: SHOW TBLPROPERTIES <table> to see all constraints
4If the constraint is too strict for legitimate data, consider relaxing it after reviewing with the data owner
5If the constraint was recently added, validate existing data before applying it to new writes

Frequently asked questions

Can I see which rows violated the constraint?

Yes — run the same filter condition as the CHECK constraint on the source dataset to find the offending rows before attempting the write.

Does Delta enforce NOT NULL differently from CHECK?

Delta enforces NOT NULL as a schema-level constraint. CHECK constraints are defined with ALTER TABLE ADD CONSTRAINT and enforce arbitrary boolean expressions.