IT 260 WEEK 1 Q1

Why should a person developing a relational database use keys in their relational database model?

Keys as they suggest by their name are part of the relational database and play important roles in the structure of the table used by database. Therefore, it is impossible for a person developing a relational database to work without keys. The ability to link tables with keys that allows for the reasonable demonstration of information that relational database provides. Keys ensure each record is uniquely identified by one or more grouping of fields within the table. They help database to implement integrity and help the relationship between tables. There are different types of keys used in the relational database and each key have specified functions in the database structure. They includes; primary keys, foreign keys, super keys and candidate keys or alternate keys

Super key

These are combination of all fields within a table that uniquely identifies each record within that table

Candidate keys

This is a single field that involves combination of fields that uniquely identifies each record in the table. The least combination of fields differentiates a candidate key from super key. Every table in the relation database must have at least one candidate key but can also have many keys. For instant the use of id to uniquely identifies each student in the student table. This would be a candidate key.

Primary keys

This is a key of reference for the table and is used all through the database to help set up the relationship within other tables. As within the candidate key, the primary keys must contain unique values but not null and identifies each record in the table uniquely.

Foreign key

This is a type of primary from one table that appears as a field in another where the first table has relationship to the second.

Secondary key

A table may have one or more choices for the primary key. There when primary keys are chosen in the table, then there are some key may not be chosen. Those not chosen are called secondary keys or alternate keys. These key are helpful as they offer alternative means of identifying a given record when the user want to put into practice the database in the RDBMS program

As discussed above it is known why the used of keys in the database are vital and must be considered by people developing relational database. Each types of keys plays different role within the database. Each key perform particular purpose such as uniquely identifying records, establishing various types of integrity, and establishing relationship between tables. You can assure sound table structure by making suitable keys are recognized for each table