A relational database's best use is organising large amounts of data. Relational databases use multiple tables when defining separate types of data, unlike other databases. Relationships between specific data points in the two tables are then linked by defining that relationship. It allows for a more systematic and clear view of the data without having to repeat information.
How Relational Databases Work
The relational database takes information with two distinct parts and puts it into two separate tables. For example, if the data being organised contains contact information of a group of students and that same group's test grades, the students' information could be categorised into two different tables. The test grades would go into one and the contact information into another. The data is linked by a certain code that appears in both tables under the same person's information.
Advantages of the Relational Database
Relational databases allow the data to be clear-cut and uncluttered. Problems arise when all the data in the previous example is only contained in one table, unlike a relational database. Since each student has multiple grades, their contact information would be entered multiple times along with each grade. This is unnecessary and can create confusion when searching the database. By having them separate, as in a relational database, contact information only needs to be entered once.
Disadvantages of the Relational Database
The main problem when using a relational database is the complexity that arises when it is first created. It is absolutely vital that the defined relationships between the tables are correct and that each set of information is linked to its pair. Although less information has to be entered in total than with other databases, making sure every point is set up correctly is a slow process. Furthermore, the relationships can become extremely intricate when a relational database contains more than just two tables.
When to Use a Relational Database
It is not always necessary to use a relational database. It can save time later on when scrutinising data for patterns or specifics, but can possibly hinder progress at the beginning. Creating a single table will provide enough organisation if the data is simple or if pieces of data only need to be entered once. To continue the previous example, if only one test grade is being organised along with contact information, only one table will be needed. It is only when certain values -- such as the address or phone number -- are being repeated that a relational database is useful.