DBMS
- 1. WELCOME TO MY PRESENTATION DBMS KARAN KUMAR DEPARTMENT OF COMPUTER SCIENCE DPG INSTITUTE OF TECHNOLOGY & MANAGEMENT
- 2. DBMS ARCHITECTURE DBMS architecture describes the structure and how the users are connected to a specific database system. The DBMS architecture is divide into three levels. (i) External level (ii) conceptual level (iii) Internal level
- 3. 3 External level External view Conceptual schema Internal schema External level External & conceptual mapping Conceptual level Conceptual & internal mapping Internal level External level:- The external level is closed to the user that is one constant in which data view Conceptual level:- It describes how the database appears to the users conceptually and the relationships between various data tables. Internal level:- It describes the actual physical storage of data or the way in which the data is actually stored in memory.
- 4. What is three-tier architecture? A THREE-WAY INTERACTION IN A CLIENT/SERVER ENVIRONMENT. The user interface is stored in the client. The bulk of the business application logic is stored in one or more servers. The data are stored in a database server.
- 5. 5 Three-tier architecture CLIENT 1 CLIENT 2 CLIENT 3 CLIENT N This is client tier Application layer Application layer is work to business logic DBMS SERVER
- 6. 6 3 Tier client server architecture Server:- A server system that takes a client request and returns a response. Ex. Facebook DBMS:- before accessing the database server it checks a lot of info so that it does not appear. The goal of Three Tier client-server architecture is: •To separate the user applications and physical database •To support DBMS characteristics •Program-data independence •Supporting multiple views of the data
- 7. 7 DATA MODELS A data model is set of concepts that can be used to describe the structure of data in a data base. A data base show the logical structure of a data base including the relationship and constraints that determine how data can be stored and accessed. Data models are use to support the development of information systems by providing the definition and format of data to involved in futures systems. Data models also gives ideas about possible alternatives to achieve targeted solution.
- 8. 8 Types of data models 1. Hierarchial model 2. Network model 3. Relational model
- 9. Hierarchial model 9 This model developed by BY IBM and north American rockwell known as information management system. This is the oldest and simplest DBMS model. The model is sorted hierarchical , either in top down or buttom up approach of designing. This model uses pointers to negative between stored data.
- 10. Example of hierarchical model 10
- 11. Advantages of hierarchical model 1. conceptual level Relationship between various level is logically very simple. Hence database structure becomes easier to view. 2. Database security Security is given by DBMS system itself. 11
- 12. Disadvantages of hierarchical complex of implementation programmers and designers need to have knowledge of physical data storage which may be complex. 2. Difficult to manage. Any change in a location of data needs change In all application programs that accesses changes data. Data access is restricted by pointer. 12
- 13. Network model This model is hierarchical model, this model also uses pointers toward data but there is no need of parent to child association. It uses graph data structure. A child can have more than one parent. It has one to many or many to many relationship. A relationship between any two record types is called as a set. Data in network model are represented by collection of records and relationship among data are represented by links. The records in the database are organized as collection of bitrary groups. 13
- 14. Example of network model 14
- 15. Relational model The relational model is first proposed by E.F cod. This model uses collection of tables to represent relationship among the data. In this model is database item is viewed as a record with attributes a set of records with similar attributes is called a TABLE. Each table contains a record of a particular type. The database uses relationship model called as RDBMS. A relation database is a collection of 2-D tables which consists of rows and columns. 15
- 16. Relational model is the most popular model and the most extensively used model. In this model the data can be storage in the tables and this shorting is called as a relation the relationals can be normalized and the normalized relation values are called atomic values. Each row in a relation contains unique value and it is called as triple each column contains value from same domain and it is called as attribute. Most of the popular commercial DBMS product like Oracle mySQL are based on relational model. 16
- 17. Example of relational mode 17