Database (DB) and Database Management System (DBMS)

What is Database - A Database is a collection of related data. - A Database is a collection of stored operational data used by the application systems of some particular enterprise. - A database is designed, built, and populated with data for a specific purpose. It has an intended group of users and some preconceived applications in which these users are interested.

What is Database - A database can be of any size and of varying complexity. - A database may be generated and maintained manually or it may be computerized.

Database Management System - Is a collection of programs that enables users to create and maintain a database. - The DBMS is a general-purpose software system that facilitates the processes of defining, constructing, and manipulating databases for various applications.

Database Management System Defining: a database involves specifying the data types, structures, and constraints for the data to be stored in the database. Constructing: the database is the process of storing the data itself on some storage medium that is controlled by the DBMS. Manipulating: a database includes such functions as querying the database to retrieve specific data, updating the database to reflect changes in the real-world, and generating reports from the data.

DB System = DB + DBMS Database SYSTEM We will call the database and DBMS software together a database system DB System = DB + DBMS

Example UNIVERSITY database for maintaining information concerning students, courses, and grades in a university environment Define: file (records), data elements, data type ( for each data element) Construct: store data in the appropriate files (note that records may be related between files) Manipulation: querying, updating.

Advantages of Using DBMS 1- Controlling Redundancy: In DBMS there has the ability to control redundancy which improve the performance of the query. The DBMS should have the capability to control this redundancy to avoid inconsistencies among the files.

Advantages of Using DBMS 2- Restricting Unauthorized Access: Users or user groups are given account numbers protected by passwords, which they can use to gain access to the database through security and authorization subsystem

Advantages of Using DBMS 3- Providing Persistent Storage for Program Objects and Data Structures: Programming languages typically have complex data structures, such as record types in PASCAL or class definitions in C++. The values of program variables are discarded once a program terminates, unless the programmer explicitly stores them in permanent files, which often involves converting these complex structures into a format suitable for file storage

Advantages of Using DBMS 4- Permitting Inference and Actions Using Rules: Deductive database systems: when database systems provide capabilities for defining deduction rules for inferring new information from the stored database facts.

Advantages of Using DBMS 5- Providing Multiple User Interfaces: A DBMS provides a variety of user interfaces: query languages for casual users; programming language interfaces for application programmers; forms and command codes for parametric users; and menu-driven interfaces and natural language interfaces for stand-alone users.

Advantages of Using DBMS 6- Enforcing Integrity Constraints: The simplest type involves specifying a data type for each data item, and a more complex type involves specifying that a record in one file must be related to records in other files.

Advantages of Using DBMS 7- Providing Backup and Recovery: Provide facilities for recovering from hardware or software failures.

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