Data Base Name COMPANY

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3 DBMS consists of a group of programs that manipulate the database and provide interface between the user of the database and other application programs It is collection of programs that enables the users to store, modify and extract the information from a data base as per the user s requirements efficiently and effectively.

4 Data Base Name COMPANY MS ACCESS MICROSOFT ORACLE ORACLE COMPANY MY SQL ORACLE COMPANY DB2 IBM SYBASE SQL LITE OPEN SOURCE SQL SERVER 2005 MICROSOFT

6 ID PASSWORD IF login valid, Then navigate to Lect. Rahul Gaba (DBU) 6

7 DATABASE MANAGEMENT SYSTEMS A DBMS is a combination of five components: hardware, software, data, users and procedures 14.7 DBMS components

8 Hardware The hardware is the physical computer system that allows access to data. Software The software is the actual program that allows users to access, maintain and update data. In addition, the software controls which user can access which parts of the data in the database. Confidentiality The data in a database is stored physically on the storage devices. In a database, data is a separate entity from the software that accesses it. 14.8

9 Users In a DBMS, the term users has a broad meaning. We can divide users into two categories: end users and application programs. Procedures The last component of a DBMS is a set of procedures or rules that should be clearly defined and followed by the users of the database. 14.9

10 Lect. Rahul Gaba (DBU) 10

11 External level In this level we decide what data is to be represented. This level describes which part of database that is relevant to each users. It is very close to end user. A user can create more than one view accordingly to their requirements. A view contains only whose portion of database which are concerned to user. There for some database has different views for different user

Current Account Bill Payment Conceptual Level Data Type varchar(16) varchar2(15) Number(15) Stored Item Saving Account

13 External Level View 1(1(Account User) Required values Saving Account Current Account Mini statement Bill Payment External Level View 2(Account office User) Required values Saving Account Current Account Field Name Saving Account Current Account Bill Payment Conceptual Level Data Type varchar(16) varchar2(15) Number(15) Stored Item Saving Account Current Account Bill Payment Mini satement Internal Level Length Type=byte(16) Type =byte16) Type = byte(16) Lect. Rahul Gaba (DBU) 13

14 Conceptual level This is the middle level in the three level architecture. This level describes what data is to be stored. This level contains logical structure of entire database. This is designed by DBA(Data base Administrator). Entities( Table):- An entity is object whose information is to be stored in the database. for example:- In student record student id entity. Attributes(Fields):- An attributes is a characteristic of interest about an entity, for i.e Roll No, class, name, address, Phone no. are the attributes of entity student

15 Attribute or Field Degree of Table is 5 Account Number Name Age Address BALANCE Row-1 Row-2 Row-3 1 ANAND GREEN RAVI 23 PREET VIHAR AJAY 32 NABHA Cardinality of Table is 3 The conceptual level must not contain any storage dependent detail. This is also known as logical level. Lect. Rahul Gaba (DBU) 15

16 Internal level The internal level determines where data is actually stored on the storage devices. The internal level interacts directly with the hardware. The internal level concerned with such things:- Storage space allocated for data. Record description for storage. Record placement. Data compression and encryption techniques

17 A Data Model is a collection of concepts that can be used to describe the structure of a database

18 Relationship One to One Parent : Child IBPS One to Many Boss : Employees RRB PO IBPS PO RRB CLERK-1 RRB CLERK-2 IBPS- CLERK The hierarchical data model organize data in a tree structure.

19 In a network data model, entities are organized in a graph, in which some entities can be accessed through several paths

20 Relational data model is the primary model, which is a combination of different relations or tables. In a relation model, data is organized in two dimensional tables called relation.

21 An Example of a Table Fields Records Name GatorLink Phone College Graff rgraff Pharmacy Harris bharris Medicine Ipswich zipswich PHHP

22 Relational data model is the primary model, which is a combination of different relations or tables. In a relation model, data is organized in two dimensional tables called relation. Record Courses Math Reasoning English G.K Computer IBPS PO IBPS CLERK RRB PO RRB CLERK

23 Table:-- 1. A table has rows and columns, also known as relation. where rows represents records and columns represent Tuple of the attribute or field. Degree of Table is 5 relation Courses Math Reasoning English G.K Computer Row-1 Row-2 Row-3 Row-4 IBPS PO IBPS CLERK RRB PO RRB CLERK Cardinality of Table is 4

24 Connectivity of a relationship describes relationship between two or more tables One to One(1:1) One to Many(1:M) Many to One(M:1) Many to Many(M:M)

26 One : Many Teacher Teaching Students

27 One : Many Skills Explorer Teaching Students

28 Many : Many Supplier Teaching Product

UNIT 1 INTRODUCTION TO DBMS 1

UNIT 1 INTRODUCTION TO DBMS 1 UNIT 1 INTRODUCTION TO DBMS 2 Example of simple college database which stores student and course information. Student: Stud-id Name Subjects Grade 1 Bob CS A 2 Tom MATH B