Advantages of using the DBMS approach
1. Controlled Redundancy
• In the file processing approach, each user defines and implements the files needed and software applications to manipulate those files.
• Various files are likely to have different formats and programs may be written in different languages and same information may be duplicated in several files.
• Data redundancy leads to
o wasted storage space,
o duplication of effort (when multiple copies of a datum need to be updated),
o a higher likelihood of the introduction of inconsistency.
• Database design stores each logical data item at one place to ensure consistency and saves storage.
• But sometimes, controlled redundancy is necessary to improve the performance.
• Database should have capability to control this redundancy & maintain consistency by specifying the checks during database design.
2. Restricting Unauthorized Access
• A DBMS provides a security and authorization subsystem, which is used by DBA to create user accounts and to specify restrictions on user accounts.
• File processing system provides password mechanism and very less security which is not sufficient to enforce security policies like DBMS.
3. Providing Persistent Storage for Program Objects
• Object oriented database systems are compatible with programming languages such as C++ and Java.
• A DBMS software automatically performs the conversion of a complex object which can be stored in object oriented DBMS, such an object is said to
be persistent due to its survival after the termination of the program.
4. Providing Storage Structures for Efficient Query Processing
• The DBMS utilizes a variety of sophisticated techniques (view, indexes etc.) to store and retrieve the data efficiently that are utilized to improve the execution time of queries and updates.
• DBMS provides indexes and buffering for fast access of query result,
the choice of index is part of physical database design and tuning.
• The query processing and optimization module is responsible for choosing an efficient query execution plan for each query submitted to the
5. Providing Backup & Recovery
• Data should be restored to a consistent state at the time system crash and changes being made
• If hardware or software fails in the middle of the update program, the recovery subsystem of DBMS ensures that update program is resumed at the point of failure.
6. Multiple user interfaces
• DBMS provides a variety of user interfaces for the users of varying level of technical knowledge.
• These includes query language for casual users, programming language interfaces for application programmers, forms and command codes for parametric users, menu driven interfaces and natural language interfaces for stand alone users etc
7. Representing Complex Relationships among data
• A DBMS must have the capability to represent a variety of complex relationship among the data, to define new relationships as they arise, and to retrieve and update the related data easily and efficiently.
8. Enforcing Integrity Constraints
• The DBMS have certain integrity constraints that hold on data.
• These constraints are derived from the meaning of the data and of the miniworld.
• Some constraints can be specified to the DBMS at the time of defining data definitions and automatically enforced.
• Database does not allow violation of constraints at the time of updating the database.
9. Permitting Inferencing and Action Using Rules
• Deductive database systems provide capabilities for defining deduction rules for inferencing new information from the stored database facts.
• Triggers can be associated with tables.
• A trigger is a form of a rule activated by updates to the table, which results in performing some additional operations to some other tables, sending messages and so on.
• Stored procedure can also be used as a part of the overall database definition and are invoked appropriately when certain conditions are met.
• Active database provides more powerful functionality by providing the active rules that can automatically initiate actions when certain events and conditions occur.