Therefore, it is important that every single record in a database has something to uniquely identify it and this is called the 'Primary Key' or sometimes the 'Key Field'. When you started school, you were given a 'student ID' or an 'office number' (primary key).
Ignoring any maintenance costs, asphalt is generally much cheaper to install than concrete. On average, the cost per square foot for asphalt will run between $2.50 to $4.00. Fluctuations in crude oil prices can cause fluctuations in asphalt prices but the price will remain around this range. Concrete, on the other hand, can run between $4.00 to $6.00 per square foot for basic installation and can cost more depending on different finishes and detail. Itâs not unheard of to have a stained concrete driveway with a smooth finish cost over $15.00 per square foot.
Concrete Walkway Average Costs. The cost of a concrete walkway is largely determined by the type of concrete poured. 1  A plain concrete walkway costs $4 to $6 per square foot. 2  Adding a single color or simple finish to the concrete raises the price to $6 to $10 per square foot. If itâs necessary to first remove existing concrete, costs will rise by approximately $2 to $6 per square foot (if hiring a pro; DIY removal is cheaper). 2  Although weâre accustomed to seeing concrete as the drab stuff of sidewalks, it actually has robust decorative potential.