OracleORA-01400
ORA-01400: Cannot Insert NULL into Column
ORA-01400 is raised when an INSERT tries to store NULL in a column that has a NOT NULL constraint. Oracle rejects the statement and no row is inserted.
Example Query
INSERT INTO employees (employee_id) VALUES (NULL); -- employee_id is defined NOT NULL
Common Causes
- 1Required column omitted from INSERT with no DEFAULT value
- 2Application passes NULL for a mandatory field
- 3Incorrect column mapping in a bulk load
How to Fix It
Always supply a value for NOT NULL columns. Add DEFAULT constraints where a fallback makes sense: column_name VARCHAR2(50) DEFAULT 'Unknown' NOT NULL. Validate source data before bulk inserts.
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