check constraint prevents duplicate values in a table code example

Example 1: check constraint prevents duplicate values in a table

CREATE TABLE sampleTable (   col1            int         NOT NULL,   col2            varchar(10) NOT NULL,   nonUniqueColumn varchar(5)  NULL,   CONSTRAINT UC_nameOfConstraint UNIQUE (contestID,keyName) );

Example 2: check constraint prevents duplicate values in a table

CONSTRAINT UC_nameOfConstraint UNIQUE (column1,column2)