Menu
How to Set a existing column of MS SQL table as NOT NULL?
271
To add not null constraint to an existing column in MySQL, we will use the ALTER command. This is a type of validation to restrict the user from entering null values.
By default, a column can hold NULL values. The NOT NULL constraint enforces a column to NOT accept NULL values. This enforces a field to always contain a value, which means that you cannot insert a new record, or update a record without adding a value to this field.
ALTER TABLE table_name ALTER COLUMN column_name DATA_TYPE [(COLUMN_SIZE)] NULL; In this syntax: First, specify the name of the table from which you want to change the column. Second, specify the column name with size which you want to change to allow NULL and then write NULL statement .
ALTER TABLE tablename ALTER COLUMN columnname datatype NOT NULL You will obviously have to make sure that the column does not contain any NULL values before doing this.
E.g.
ALTER TABLE orders ALTER COLUMN customer_id INT NOT NULL If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
