check constraint prevents duplicate values in a table
snippet in c
check constraint prevents duplicate values in a table
user6097
CREATE TABLE sampleTable ( col1 int NOT NULL, col2 varchar(10) NOT NULL, nonUniqueColumn varchar(5) NULL, CONSTRAINT UC_nameOfConstraint UNIQUE (contestID,keyName) );
check constraint prevents duplicate values in a table
user4457
CONSTRAINT UC_nameOfConstraint UNIQUE (column1,column2)