If a database is shared with several people over a network, you should consider splitting it. Splitting a database reorganizes it into two files — a back-end database that contains the database's tables, and a front-end database that contains all the other database objects such as queries, forms, and reports.
There are a number of benefits to splitting a database, including:
Enhanced Security: If you have saved a back-end database to your computer that uses the NTFS file system, you can use the NTFS security features to secure your data. Since users will access the back-end database through linked tables, it is more difficult for unauthorized users to access data from the front-end database.
Greater Availability: Since a split database's data is sent across the network, actions made in it are usually quicker to complete, which allows the data to be more available to edit.
Improved Performance: Splitting a database usually significantly improves its performance because only its objects' data are sent across the network, not its actual objects.