NOT NULL- This constraint is
responsible for a column to confirm that a column cannot have a null value.
Example-
Following we create
new table PRODUCT and add six columns where ID, SKU, TITLE, PRICE specify not
to accept NULLs.
CREATE TABLE PRODUCT
(
ID INT NOT NULL,
SKU VARCHAR(20) NOT NULL,
TITLE VARCHAR(200) NOT NULL,
PRICE MONEY NOT NULL,
DESCRIPTION VARCHAR(2000) NULL,
DTCREATE DATETIME NULL
)
|
If PRODUCT table already created, then to add a NOT NULL constraint to the SKU column, we use the following query.
ALTER TABLE PRODUCT ALTER COLUMN SKU VARCHAR (20) NOT NULL
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