How do integrated databases handle data redundancy?

Integrated databases handle data redundancy by implementing data normalisation and using unique identifiers for each data entry.

Data redundancy is a common issue in database management, and integrated databases handle this through a process known as data normalisation. Normalisation is a systematic approach of decomposing tables to eliminate data redundancy and undesirable characteristics like insertion, update and deletion anomalies. It is a multi-step process that puts data into tabular form by removing duplicated data from the relation tables.

Normalisation involves dividing a database into two or more tables and defining relationships between the tables. The main objective of normalisation is to isolate data so that additions, deletions, and modifications of a field can be made in just one table and then propagated through the rest of the database via the defined relationships. This ensures that the database is free from insertion, update and deletion anomalies.

Another way integrated databases handle data redundancy is through the use of unique identifiers for each data entry. These unique identifiers, often referred to as primary keys, ensure that each record within the database is distinct and can be identified separately from every other record. This prevents duplicate entries from being created and helps maintain the integrity of the data within the database.

Furthermore, integrated databases may also use referential integrity constraints to handle data redundancy. Referential integrity is a property of data stating that all its references are valid. It requires that the value in a foreign key column will always point to an existing row. If a piece of data is referenced from another table, the referenced data needs to exist. This prevents data redundancy and ensures that the relationships between tables in the database are maintained.

In conclusion, integrated databases handle data redundancy through a combination of data normalisation, the use of unique identifiers, and the enforcement of referential integrity constraints. These techniques help to ensure that the data within the database is accurate, consistent, and reliable.