BCA_Sem-3_DBMS_Unit-1

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2 Unit 1: DBMS Development Concept An introduction to DBLC, Degree of Data Abstraction www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

3 Database Life Cycle The database life cycle (DBLC) defines the stages involved for implementing a database, starting with requirements analysis and ending with monitoring and modification. Furthermore, the DBLC never ends because database monitoring, modification, and maintenance are part of the life cycle, and these activities continue long after a database has been implemented. www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

Five stages in the database 4 life cycle are 1.Requirements analysis 2.Logical design 3.Physical design 4.Implementation 5.Monitoring, modification, and maintenance www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

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6 RequirementS analysis Requirements Analysis is the first and most important stage in the Database Life Cycle. It is the most labor-intensive for the database designer. This stage involves assessing the informational needs of an organization so that a database can be designed to meet those needs. www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

7 Logical design During the first part of Logical Design, a conceptual model is created based on the needs assessment performed in stage one. A conceptual model is typically an entity-relationship (ER) diagram that shows the tables, fields, and primary keys of the database, and how tables are related (linked) to one another. 1.conceptual model: A description of the structure of a database. 2.Entity-relationship (ER) diagram: A diagram used during the design phase of database development to illustrate the organization of and relationships between data during database design. 3.Normalization: The process of applying increasingly stringent rules to a relational database to correct any problems associated with poor design. www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

Physical Design 8 The Physical Design stage has only one purpose: to maximize database efficiency. This means finding ways to speed up the performance of the RDBMS. Manipulating certain database design elements can speed up the two slowest operations in an RDBMS: retrieving data from and writing data to a database. www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

Implementation 9 During the implementation stage of the DBLC, the tables developed in the ER diagram (and subsequently normalized) are converted into SQL statements. These SQL statements are then executed in the RDBMS to create a database. By this stage in the database life cycle, the System Administrator has installed and configured an RDBMS. www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

Monitoring, modification, 10 and maintenance A successfully implemented database must be carefully monitored to ensure that it is functioning properly and that it is secure from unauthorized access. The RDBMS usually provides utilities to help monitor database functionality and security. Database modification involves adding and deleting records, importing data from other systems (as needed), and creating additional tables, user views, and other objects and tools. As an organization grows, its information system must grow to remain useful. www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

11 Degrees of Data Abstraction in DBMS www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

The External Model: 12 The external model is the end users’ view of the data environment. The term end users refers to people who use the application programs to manipulate the data and generate information. End users usually operate in an environment in which an application has a specific business unit focus. Companies are generally divided into several business units, such as sales, finance, and marketing. www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

13 The use of external views representing subsets of the database has some important advantages: • It makes it easy to identify specific data required to support each business unit’s operations. • It makes the designer’s job easy by providing feedback about the model’s adequacy. Specifically, the model can be checked to ensure that it supports all processes as defined by their external models, as well as all operational requirements and constraints. • It helps to ensure security constraints in the database design. Damaging an entire database is more difficult when each business unit works with only a subset of data. • It makes application program development much simpler. www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

The Conceptual Model: 14 The conceptual model represents a global view of the entire database as viewed by the entire organization. That is, the conceptual model integrates all external views (entities, relationships, constraints, and processes) into a single global view of the data in the enterprise. www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

15 First, it provides a relatively easily understood bird’s-eye (macro level) view of the data environment. • Second, the conceptual model is independent of both software and hardware. Software independence means that the model does not depend on the DBMS software used to implement the model. • Hardware independence means that the model does not depend on the hardware used in the implementation of the model. Therefore, changes in either the hardware or the DBMS software will have no effect on the database design at the conceptual level. Generally, the term logical design is used to refer to the task of creating a conceptual data model that could be implemented in any DBMS. www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

The Physical Model: 16 The physical model operates at the lowest level of abstraction, describing the way data are saved on storage media such as disks or tapes. The storage structures used are dependent on the software (the DBMS and the operating system) and on the type of storage devices that the computer can handle. www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

Textbooks / Reference Books 17 TEXT BOOKS T1 Elmasri & Navathe, Fundamentals of Database Systems, Fourth Edition. T2 C. J. Date, Introduction to Database Management System. REFERENCE BOOKS R1 Bipin C. Desai, An Introduction to Database Management Systems, PHI, New Delhi www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL

18 THANK YOU www.cuidol.in Unit-1(MAP-607) All right are reserved with CU-IDOL