SQLCODE -407 null inserted into non-null column

SQLCODE -407: null inserted into a NOT NULL column — the program tried to store null where nulls are forbidden.

What it means

• After every EXEC SQL, DB2 returns a SQLCODE: 0 means success, +100 means no row found, and negative values mean an error.

Common causes

• Indicator variable set to null for a NOT NULL column.
• Missing value defaulted to null.

How to diagnose

• Check which column is NOT NULL and what the program passed.
• Inspect indicator variables.

How to fix it

• Supply a real value or a DEFAULT.
• Fix the program logic that leaves the value unset.

Example: Supply values for NOT NULL columns

Defaults beat nulls for NOT NULL columns.

Interview tip

• Q: How would you troubleshoot a SQLCODE -407 null inserted into non-null column in production?
• A: I would check the SQLCODE and SQLERRM immediately after the failing statement, reproduce in SPUFI, then apply the specific fix.

Prevention checklist

• Always check SQLCODE after every EXEC SQL statement.
• Log the SQLCODE, SQLSTATE and failing statement for support.