1. Why would you choose a database system instead of simply storing data in operation system file? When would it make sense not to use a database system?
Answers
Answer:
A database is a collection of data. A database system or database management system is software that is used for creating and managing databases. A file system is software which is used for organizing data.
The advantages of database system over file systems are:
• Data Independence: DBMS provides data independence; application programs are independent of the structure, representation of data.
• Data Access: DBMS provides efficient access of data, faster retrieval of data when compared to file systems, as DBMS provides indexing and query optimization mechanisms which provide efficient access.
• Data integrity and security: protection to the data is achieved using DBMS by controlling the access to the data objects and by imposing constraints integrity of the data is achieved. Only the data satisfying the definition of the data objects can be stored.
• DBMS provides concurrency control. That is all the transactions are executed in such a way that the database is always in a consistent state and all the conflicting transactions are rejected.
• Crash Recovery: DBMS maintains log files and has mechanisms which recover the system to a consistent state after a crash.
• Application development time is less due to the above advantages.