introduction to data batabase

Database


Database: 

 The database is a well-organized collection of interrelated data. 
It has the following properties:

  1. It is well organized.
  2. The data should be stored only once.
  3. The data can be an accessed difficulty.
  4. The data should be atomic.


DBMS: 

(database management system)
A software which is used to control the overall system of database i.e. creation of a database, manipulation of a database, updating of the database, deletion of unnecessary data from the database is called database management system.

FUNCTION OF DBMS: 

1. Query processing: Query is a statement which is used to perform any task on the database. DBMS used for query processing.
2. Data model: The collection of data is called a data model. DBMS is responsible for the construction of the data model.
3. Concurrency control: DBMS supports sharing property. Hence DBMS an environment such that any users can access database concurrency.
4. Crash recovery and safety: When the database is crashed then DBMS provides an environment to recover the data and provides safety.

What are the disadvantages of file processing system ? or
Why can we use the database in place of file processing system?

  1. Difficulty in accessing data.
  2. Concurrent access anomaly.
  3. Security problem.
  4. Integrity problem (correctness and validity)
  5.  Anomaly problem.
  6. Inconsistent.
  7. Data can be redundant.


What is the instance of the Database?

The data of database changes over time, as the information is inserted or deleted. The collection of information stored in the database at a particular moment is called an instance of the database. i.e. The snapshot of the data at any instant of time is called relational instant.

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