What is data dictionary? What are its advantages

A data dictionary is similar to the glossary or index that can be found in the back of a book; the difference is that a data dictionary is electronic and is associated with electronic databases. A data dictionary is a very important element of a database as it provides information about a database and the information that it contains; having a data dictionary makes it easier for users of the database to find what they need without having to actually go through the database.

The data dictionary can be in the form of a simple text file, or it can include charts and diagrams to express the information; the only requirement for a data dictionary is that it has to be in a location that is easily accessible to all database users.For instance, a database is typically built by several persons and used by several persons, since each builder may use a different format for the section they create, it would be difficult for the database administrator or users to know how to make entries into the various sections of the database; the data dictionary takes care of this problem as it provides information on the type of data that should be used in each field. A data dictionary provides no actual data from the database; it only provides information on how to manage the data that is in the database.