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'.
Concrete is a highly affordable building material that will work with almost any budget. The traditional concrete driveway starts at $4 per square foot and stops at around $10 per square foot.Sealed concrete usually costs a little more. Homeowners can expect to add between $2 and $4 per square foot for the detailing work done on the top of the driveway.oncrete is a highly affordable building material that will work with almost any budget. The traditional concrete driveway starts at $4 per square foot and stops at around $10 per square foot.