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Defines and describes the process of Database Management
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DBMS DESIGN PROCESS
Tayyab Hameed, Univseristy of Lahore, Islamabad CampusMIS
Database & Management System Database
Carefully designed and constructed repository of facts.
Part of an information system. Management System
A management system is the framework of processes and procedures used to ensure that an organization can fulfill all tasks required to achieve its objectives.
Database Management System A database management system (DBMS) is a collection of
programs that enables an organization to store, modify, and extract information from a database.
Types of DBMS There are different types of DBMSs:
Small systems that run on personal computers. Huge systems that run on main frames.
The following are examples of database management systems: Computerized library Flight reservation systems Inventory management systems and many more……
Database Design The process of producing a detailed data model of a database
containing all the needed logical and physical design choices and physical storage parameters needed to generate a design of a database.
Database design must reflect the IS, of which the database is a part. Information systems undergo evaluation and revision within a
framework known as the Systems Development Life Cycle (SDLC). Databases also undergo evaluation and revision within a framework
known as the Database Life Cycle (DBLC). There are two general design strategies exist:
Top-down vs. bottom-up design Centralized vs. decentralized design (Con’t.)
DBMS Design Process
User
(Someone doing “real work” )
Infrastructure(Computer and Human)
Management(Organization)
Successful DBMS design requires an interlocking of the :
Systems Development Life Cycle
(Con’t.)
Systems Development Life Cycle Planning
Should the existing system be continued, modified or replaced?
The technical of hardware and software requirements. The system cost.
Analysis What are the precise requirements of the current
system’s end users? Do these requirements fit into the overall information
requirements? (Con’t.)
Systems Development Life Cycle Detailed System Design – the designer completes
the design of the system’s processes including all the necessary technical specifications for the screens, menus, reports, and other devices that might be used in help to make the system a more efficient information generator.
Implementation Install the hardware, the DBMS software, and application
programs. The system enters into a cycle of coding, testing, and
debugging, until it is read to delivered. (Con’t.)
Systems Development Life Cycle
The actual database is created, and the system is customized, by using a variety of methods and devices: Customized user programs Database interface programs Conversion programs that import the data from a different file
structure, using batch programs, a database utility, or both. Maintenance
Corrective maintenance in response to system errors. Adaptive maintenance due to changes in the business
environment. Perfect maintenance to enhance the system.
Database Design
(Con’t.)
Database Lifecycle (DBLC)
(Con’t.)
Phase 1: Database Initial Study Purposes
Analyze company situation Operating environment Organizational structure
Define problems and constraints Define objectives What is the proposed system’s initial
objective? Will the system interface with other existing or future systems
in the company? Will the system share the data with other systems or users?
Define scope and boundaries (Con’t.)
Initial Study Activities
(Con’t.)
Phase 2: Database Design Most Critical DBLC phase Makes sure final product meets requirements Focus on data requirements Sub-phases
I. Create conceptual design II. DBMS software selection III. Create logical design IV. Create physical design (Con’t.)
I. Conceptual Design Data modeling creates abstract data
structure to represent real-world items High level of abstraction Four steps
Data analysis and requirements Entity relationship modeling and normalization Data model verification Distributed database design
(Con’t.)
Data analysis and Requirements
Data analysis and Requirements Focus on:
Information needs Information users Information sources Information constitution
Data sources Developing and gathering end-user data views Direct observation of current system Interfacing with systems design group Business rules (Con’t.)
II. DBMS Software Selection DBMS software selection is critical Advantages and disadvantages need study Factors affecting purchasing decision
Cost DBMS features and tools Underlying model Portability DBMS hardware requirements (Con’t.)
III. Logical Design Translates conceptual design into internal model Maps objects in model to specific DBMS constructs Design components
Tables Indexes Views Transactions Access authorities Others
(Con’t.)
IV. Physical Design Selection of data storage and access
characteristics Very technical More important in older hierarchical and network
models Becomes more complex for distributed
systems Designers favor software that hides physical
details (Con’t.)
Phase 3: Implementation and Loading
Creation of special storage-related constructs to house end-user tables. Data loaded into tables. Other issues:
Performance Security Backup and recovery Integrity Company standards Concurrency controls (Con’t.)
Phase 4: Testing and Evaluation Database is tested and fine-tuned for
performance, integrity, concurrent access, and security constraints
Done in parallel with application programming Actions taken if tests fail
Fine-tuning based on reference manuals Modification of physical design Modification of logical design Upgrade or change DBMS software or hardware (Con’t.)
Phase 5: Operation Database considered operational Starts process of system evaluation Unforeseen problems may surface Demand for change is constant
(Con’t.)
Phase 6: Maintenance and Evaluation
Preventative maintenance Corrective maintenance Adaptive maintenance Assignment of access permissions Generation of database access statistics to monitor
performance Periodic security audits based on system-generated
statistics Periodic system usage-summaries (Con’t.)
DB Design Strategy Notes Top-down
1) Identify data sets 2) Define data elements
Bottom-up 1) Identify data elements 2) Group them into data sets
Top-Down vs. Bottom-Up
(Con’t.)
Centralized vs. Decentralized Design
Centralized design Typical of simple databases Conducted by single person or small team
Decentralized design Larger numbers of entities and complex
relations Spread across multiple sites Developed by teams (Con’t.)
Centralized Design
(Con’t.)
Decentralized Design
(Con’t.)
Database Management System Oracle Database Server MS SQL Server DB2 MySQL Many more………
(Con’t.)
Most problems are non-technical Poorly selected data Badly organized data Incorrect data models Software has limited capability (oversell) Systems managers underestimate time
requirements Systems can be underutilized Systems can be (and have been) abandoned Personnel problems
(Con’t.)
Bibliographic Reference: Management Information Systems by
Kenneth C Laudon_Jane P Laudon http://predoc.org/download/docs-100865/100865
.doc
http://www.shsu.edu/~csc_tjm/summer2000/cs334/Chapter06/Chapter6.html
THE END !!!!!!