1 Welcome: To the second learning sequence “ Data Base (DB) and Data Base Management System (DBMS) “ Recap : In the previous learning sequence, we discussed the basic definitions of Data base subject. Present learning: We shall explore the following topics: - What is DB ? - What is DBMS? - Advantages of using DBMS.

2 What is DATA BASE - A data base is a collection of stored operational data used by the application systems of some particular enterprise.

3 What is DATA BASE - A data base is a collection of stored operational data used by the application systems of some particular enterprise. - A data base is a collection of related data.

4 What is DATA BASE - A data base is a collection of stored operational data used by the application systems of some particular enterprise. - A data base is a collection of related data. - 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.

5 What is DATA BASE - A database can be of any size and of varying complexity.

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

7 Database Management System - Is a collection of programs that enables users to create and maintain a database.

8 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 9 DBMS Definition Manipulating Constructing Administration

Database Management System 10 Definition (2) Removing data structures (1) Defining new data structures (3) Modifying the structure of existing data.

Database Management System 11 Constructing (2) Modifying data (1) Inserting data (3) Deleting data

Database Management System 12 Manipulating (2) Generating reports from the data. (1) Querying the Database to retrieve specific data

Database Management System 13 Administration (3) monitoring performance (1) Registering and monitoring users (4) maintaining data integrity (6) covering information If the system fails. (2) enforcing data security (5) dealing with concurrency control

14 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 and generating reports from the data. - Administration : Registering and monitoring users, enforcing data security, monitoring performance, maintaining data integrity, dealing with concurrency control, and recovering information if the system fails.

15 DATA BASE SYSTEM We will call the database and DBMS software together a database system

16 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.

17 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 so as to avoid inconsistencies among the files.

18 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

19 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

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

21 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.

22 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.

23 Advantages of Using DBMS 7- Providing Backup and Recovery: Provide facilities for recovering from hardware or software failures (The backup and recovery subsystem ).

24 Summary: In this learning sequence, we discussed the following topics: - what is DB and DBMS? - Advantages of DBMS.

25 END