this ppt is for database management systemthis ppt is for database management systemthis
- 1. Presentation on DATABASE MANAGEMENT SYSTEM
- 2.  A database is a collection of related information stored in a organized manner so that it is available to many users for different purposes. The content of a database is obtained by combining data from all the different sources in an organization. So that data are available to all users and redundant data can be eliminated. BASIC CONCEPTS OF DATABASE
- 3.  An organization must have accurate and reliable data for effective decision making. To this end, the organization maintains records the various facets of its operations by building appropriate models of the diverse classes of objects of interest. These models capture the essential properties of the objects and record relationships among them. Such related data is called a Database. A Database System is an integrated collection of related files, along with details of the interpretation of the data contained therein.
- 4.  Eliminate redundant data as much as possible.  Integrate existing data files.  Share data among all users.  Incorporate changes easily and quickly.  Simplify the use of data files.  Maintenance of Data Security  Lower the cost of storing and retrieving data.  Improve accuracy and consistency.  Provide data security from unauthorized use.  Exercise central control over standards. General objectives in establishing a Database
- 5.  File Consolidation  Program and file independence  Access Versatility  Data Security  Program Development  Program Maintenance  Special Information Advantages of Database
- 6.  The management of data in a database system is done by means of a general purpose software package called DBMS.  The primary goal of the DBMS is to provide an environment that is both convenient and efficient to use in retrieving and storing database information. What is DBMS?
- 7.  A Database Management System is a software system that allows access to data contained in a database. The objective of the DBMS is to provide a convenient and effective method of defining, storing, and retrieving the information contained in the database. The DBMS interfaces with application programs, so that data contained in the database can be used by multiple applications and users.
- 8.  Creating of a file, addition, Deletion, modification of data and of entire files.  Retrieving data collectively/selectively.  The data can be sorted/indexed.  Various reports can be produced.  It can perform desired calculations.  To maintain data integrity and database use. DBMS - facilities/capabilities
- 9.  ORACLE  SYBASE  INGRESS  Microsoft ACCESS  FoxBASE  FoxPro  Dbase Commercially available DBMS Software are
- 10.  Although it has some means of describing the physical database model, It is basically useful in the design of logical database model.  It is used to organize data as a relation, normalizing relations and finally obtaining a relational database model. ENTITY-RELATIONSHIP MODEL
- 11.  Entities : An entity is a person, place, thing, or event of interest to the organization and about which data are captured, stored or processed. For example, an Employee is an entity. An entity type or entity set is a group of similar objects of concern to an organization for which it maintains data.  Attributes : Which specify properties of entities and relationships.  Relationship :Which connect entities and represent meaningful dependencies between them. In general we can say that an employee works in some department. E-R MODEL BASICS
- 12.  The data is perceived by the user as relations ( and nothing but relations); and  The operators are at the user’s disposal, for data retrieval - the operators that generate new relations from old, include at least SELECT, PROJECT, UNION and JOIN Definitions Related to Relational Model
- 13.  Primary key : The PK is the kind of key that is chosen by the database designer as the principal means of identifying entities within an entity set.  Foreign key : If a non-key attribute in one relation appears as the primary key ( or part of the primary key ) in another relation, it is called foreign key RELATIONAL DATA INTEGRITY
- 14.  Data Definition Language : It includes all the entity sets and their attributes as well as the relationships among the entity sets. It also includes any constraints that have to be maintained, including the constraints on the value that can be assigned to different attributes in the same or different records. Example : Create Table,Index,View DBMS FACILITIES
- 15.  Data Manipulation Language : It enables users to access or manipulate data from the database, insertion of new data into the database, and deletion or modification of existing data. The first of these data manipulation operation is called a QUERY. Examples : Select, Insert, Update, Delete
- 16.  No data value should be duplicated in different rows unnecessarily.  A value must be specified for every attribute in a row.  Each relation should be self-contained.  When a row is added to a relation, other relations in the database should not be affected.  A value of an attribute in a tuple may be changed independent of other tuples in the relation and other relations. PROPERTIES OF NORMALIZED RELATIONS
- 17. ORD_NO ORD_DT IT_CODE QTY PRICE 1456 26/02/2021 3687 52 50 1456 26/02/2021 4627 38 60 1456 26/02/2021 3214 20 17 1886 27/02/2021 4629 45 20 1886 27/02/2021 4627 30 60 1788 28/02/2021 4627 40 60 NORMALIZED FORM OF RELATION TABLE : ORDER_DETAILS