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Description

This error occurs when a SQL `INSERT` or `UPDATE` statement attempts to store a `NULL` value into a database column that is defined with a `NOT NULL` constraint. It signifies that a required data field has been left empty or explicitly set to `NULL`, violating the table's schema definition.

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Error Message

Column '%s' cannot be null

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Known Causes

3 known causes

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Application Did Not Provide Data

An application or script attempted to insert or update a row without providing a value for a column that is marked as `NOT NULL`.

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SQL Query Omitted Value

The `INSERT` or `UPDATE` SQL statement explicitly omitted a column that is defined as `NOT NULL`, or explicitly set its value to `NULL`.

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No Default Value Set

The `NOT NULL` column does not have a `DEFAULT` value defined, meaning the database cannot automatically provide a value if one is not supplied.

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Solutions

3 solutions available

1. Provide Value for NOT NULL Column easy

Include value in INSERT statement

1

Include all NOT NULL columns in INSERT

-- Wrong: missing required column
INSERT INTO users (email) VALUES ('test@example.com');

-- Correct: include name (NOT NULL column)
INSERT INTO users (name, email) VALUES ('John', 'test@example.com');

2. Set Default Value for Column easy

Add default so NULL isn't needed

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Alter column to have default value

ALTER TABLE users ALTER COLUMN status SET DEFAULT 'active';

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Or modify column definition

ALTER TABLE users MODIFY COLUMN status VARCHAR(20) NOT NULL DEFAULT 'active';

3. Allow NULL Values easy

Remove NOT NULL constraint if appropriate

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Make column nullable

ALTER TABLE users MODIFY COLUMN phone VARCHAR(20) NULL;

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Related Errors

5 related errors

MariaDB Error 1048: Null Value Not Allowed