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'.
on average getting concrete floors can cost anywhere from as little as $ 2 to as much as $ 17 per square foot an economical option which can just change the tone of the concrete floor will typically cost less than $ 6an elaborate finish which can come in many various designs and application techniques can cost upwards of $ 10 per square foothe cost of concrete floors will depend on the style that you choose for your home the size of the room and the professional contractor performing the job