unique and null
UNIQUE clause and NULL in SQL Server 2012
In this topic You find out how work UNIQUE constraint for column with or without NOT NULL constraint.
Begin with creating i ... one NULL value. If You would like to constraints this field for NOT NULL, You may add NOT NULL to column with UNIQUE clause.
UNIQUE clause and NULL in SQL Server 2012
In this topic You find out how work UNIQUE constraint for column with or without NOT NULL constraint.
Begin with creating i ... one NULL value. If You would like to constraints this field for NOT NULL, You may add NOT NULL to column with UNIQUE clause.
UNIQUE clause and NULL in SQL Server 2012
In this topic You find out how work UNIQUE constraint for column with or without NOT NULL constraint.
Begin with creating i ... one NULL value. If You would like to constraints this field for NOT NULL, You may add NOT NULL to column with UNIQUE clause.