Importance of data model

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Importance of data model

  1. 1. IMPORTANCE OFDATA MODEL
  2. 2.  Data models can facilitate interaction among the designer, the application programmer and the end user.
  3. 3.  A well- developed data model can even foster improved understanding of the organization for which the database design is developed.
  4. 4.  Data models are a communication tool.
  5. 5. ADVANTAGES andDISADVANTAGES of
  6. 6. HIERARCHICALDATA MODEL
  7. 7. ADVANTAGES: It promotes data sharing. Parent/child relationship promotes conceptual simplicity. Database security is provided and enforce by DBMS.
  8. 8. ADVANTAGES: Parent/child relationship promotes data integrity. It is efficient with 1:m relationship.
  9. 9. Disadvantages: Complex implementation requires knowledge of physical data storage characteristics. Navigational system yields complex application development, management, and used; requires knowledge of hierarchical path.
  10. 10.  Changes in structure require changes in all applications. There are implementation limitation. There is no data definition or data manipulation language in DBMS. There is a lack of standards.
  11. 11. NETWORKDATA MODEL
  12. 12. ADVANTAGES: Conceptual simplicity is at least equal to that of the hierarchical model. It handles more relationship type, such as m:n and multi-parent. Data access is more flexible.
  13. 13. ADVANTAGES: Data owner/ member promotes data integrity. There is conformance to standards. It includes data definition language (DDL) and data manipulation language (DML)
  14. 14. DISADVANTAGES: System complexity limits efficiency. Navigational system yields complex implementation, application development and management. Structural changes require changes in all application programs.
  15. 15. RELATIONALDATA MODEL
  16. 16. ADVANTAGES: Structural independence is promoted by the use of independent tables. Changes in a tables structure do not affect data access or application programs. Tabular view substantially improves conceptual simplicity, thereby promoting easier database design, implementation, management and use.
  17. 17. ADVANTAGES: AD HOC query capability is based on SQL. Powerful RDBMS isolates the end user from physical level details and improves implementation and management simplicity.
  18. 18. DISADVANTAGES: The RDBMS requires substantial hardware and system software overhead. Conceptual simplicity gives relatively untrained people the tools to use a good system poorly, and if unchecked, it may produce the same data anomalies found in file systems.
  19. 19. DISADVANTAGES: IT may promote island of information.
  20. 20. ENTITY RELATIONSHIP DATA MODEL
  21. 21. ADVANTAGES: Visual modeling yields exceptional conceptual simplicity. Visual representation makes it an effective communication tool. It is integrated with dominant relational model.
  22. 22. Disadvantages: There is limited constraints representation. There is limited relationship representation There is no DML. Loss of information content occurs when attributes are removed from entities to avoid crowded displays.
  23. 23. OBJECT- ORIENTED DATA MODEL
  24. 24. ADVANTAGES: Semantic content is added. Visual representation includes semantic content. Inheritance promotes data integrity.
  25. 25. Disadvantages: Slow development of standards caused vendors to supply their own enhancements, thus eliminating a widely accepted standards. It is a complex navigational systems.
  26. 26. Disadvantages: There is a steep learning curve. High system overhead slows transactions.

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