NOT NULL constraint

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Details

• INSERT or UPDATE statements containing NULL values are rejected. This includes INSERT statements that do not include values for any columns that do not have a DEFAULT value constraint. For example, if the table foo has columns a and b (and b does not have a DEFAULT VALUE), when you run the following command:
  > INSERT INTO foo (a) VALUES (1);
  
  CockroachDB tries to write a NULL value into column b. If that column has the NOT NULL constraint, the INSERT statement is rejected.
• To add the NOT NULL constraint to an existing table column, use the ALTER COLUMN statement.
• For more information about NULL, see NULL handling.

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Syntax

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Usage example

> CREATE TABLE IF NOT EXISTS customers (
    customer_id INT         PRIMARY KEY,
    cust_name   STRING(30)  NULL,
    cust_email  STRING(100) NOT NULL
  );

> INSERT INTO customers (customer_id, cust_name, cust_email) VALUES (1, 'Smith', NULL);

pq: null value in column "cust_email" violates not-null constraint

> INSERT INTO customers (customer_id, cust_name) VALUES (1, 'Smith');

pq: null value in column "cust_email" violates not-null constraint

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See also

• Constraints
• DROP CONSTRAINT
• CHECK constraint
• DEFAULT constraint
• REFERENCES constraint (Foreign Key)
• PRIMARY KEY constraint
• UNIQUE constraint
• SHOW CONSTRAINTS
• NULL HANDLING