Database Normalisation Questions Medium
In database normalization, a composite key refers to a key that consists of two or more columns in a table. It is used to uniquely identify a record in a table when a single column cannot provide a unique identifier.
The concept of composite keys is important in database normalization as it helps in eliminating data redundancy and maintaining data integrity. By combining multiple columns to form a composite key, we can ensure that each record in a table is uniquely identified.
Composite keys are typically used in situations where a single column cannot uniquely identify a record. For example, in a table that stores information about students, a composite key may be formed by combining the student's first name and last name columns. This ensures that no two students with the same first and last names can be entered into the table.
By using composite keys, we can avoid data duplication and maintain the integrity of the database. It allows for efficient querying and retrieval of data, as the combination of multiple columns provides a more specific and unique identifier for each record.
However, it is important to note that the use of composite keys should be limited to situations where it is necessary. Overuse of composite keys can lead to increased complexity and may affect the performance of the database. Therefore, it is essential to carefully analyze the requirements and design of the database before deciding to use composite keys.