A primary key is a candidate key that is most appropriate to be the main reference key for the table. As its name suggests, it is the primary key of reference for the table and is used throughout the database to help establish relationships with other tables.
1 A concrete driveway with several decorative elements can cost $12 -$18 a square foot, or $3,600 -$5,400 for 12'x25' or $11,500 -$17,500 for 24'x40'.
Cost: $1,660, based on an average $11.50 per square foot. Details: From basic brushed to decorative stamped, concrete offers a range of decorative options at a lower price than other materials and lower labor fees.