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'.
If so, you'll have to add that cost. Here are a few average costs to get you started on your estimate. As you know, none of these is the sum total of a concrete patio cost. +The average cost of stamped concrete is $9-$13 per square foot. +The average cost of installing a concrete slab is $6 - $10 per square foot.