Distinguish between the primary key and a candidate key. Provide an example of each.
What requirements must a two-dimensional table satisfy in order to be a relation? Provide an example of a table that is a relation.
The primary key is a candidate key that the IT professional has selected that acts to identify the rows in a table. The primary key is typically chosen based upon the amount of foreign key data that needs to be generated. The primary key is used for four distinct tasks, including identifying table rows, and then representing the rows into a relationship. The other two duties include organizing the relation of storage and for use in indexes to improve operational performance. A good use of a primary key would be a key internally generated "that has no meaning outside of the database system" (Chapple, 2012). This would then be used as an auto number to create a record identification, which would be automatically generated in specific order each time a new record is created by the user.
The candidate ...
This solution discusses primary and candidate keys, and also discusses the requirements needed for a two dimensional table in order to be a relation. References are provided for both questions.