The contents of a distributed database are spread across multiple locations. That means the contents may be stored in different systems that are located in the same place or geographically far away. However, the database still appears uniform to the users i.e the fact that the database is stored at multiple locations is transparent to the users.
The different components of a distributed database are:
Let us now discuss them one by one:
There are many users who use the distributed database. For them, the fact that the database is spread across multiple locations is transparent and they perceive the database to be one whole construct.
The global schema shows the overall design of the database. It helps to logically understand the design of the whole database as in reality the database is not stored at any one place and spread over various systems.
The database modules are the parts of the database stored in multiple locations. In homogeneous distributed database, all these parts contain the same data model while in heterogeneous distributed database, the parts may have different data models.