Introduction to RDBMS


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– Raw facts; building blocks of information
– Unprocessed information
– Data processed to reveal meaning
• Accurate, relevant, and timely information is key
to good decision making.

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Introduction to RDBMS

  1. 1. Relational Database Management Systems
  2. 2. Books? Software required?
  3. 3. Data vs. Information Data: – Raw facts; building blocks of information – Unprocessed information Information: – Data processed to reveal meaning– Data processed to reveal meaning • Accurate, relevant, and timely information is key to good decision making. • Good decision making is key to survival in global environment
  4. 4. Manual File Systems • Traditionally composed of collection of file folders kept in file cabinet. • Organization within folders was based on data’s expected use (ideally logically related).expected use (ideally logically related). • System was adequate for small amounts of data with few reporting requirements. • Finding and using data in growing collections of file folders became time-consuming and cumbersome
  5. 5. Conversion from Manual File System to Computer File System • Could be technically complex, requiring hiring of data processing (DP) specialists. • DP specialists created file structures, wrote software, and designed application programs.designed application programs. • Resulted in numerous “home-grown” systems being created. • Initially, computer files were similar in design to manual files (see Figure 1.3)
  6. 6. Contents of Customer File
  7. 7. Basic File Terminology
  8. 8. A Simple File System
  9. 9. Problems with File System Data Mgmt. • Wastage Of Resources • Work Overload • No Query Apply• No Query Apply • Redundancy • Data Inconsistency
  10. 10. Data Redundancy& Data Inconsistency • Data redundancy results in data inconsistency – Different and conflicting versions of the same data appear in different places • Errors more likely to occur when complex entries• Errors more likely to occur when complex entries are made in several different files and recur frequently in one or more files • Data anomalies develop when required changes in redundant data are not made successfully
  11. 11. Introducing the Database & the DBMS • Database—Large Repository of data shared, integrated computer structure that houses:that houses: – End user data (raw facts) – Metadata (data about data)
  12. 12. DBMS (continued) • DBMS (database management system): – Collection of programs that manages database structure and controls access to data – Possible to share data among multiple– Possible to share data among multiple applications or users – Makes data management more efficient and effective
  13. 13. DBMS Makes Data Management More Efficient and Effective • End users have better access to more and better-managed data – Promotes integrated view of organization’s operationsoperations – Probability of data inconsistency is greatly reduced – Possible to produce quick answers to ad hoc queries
  14. 14. The DBMS Manages the Interaction Between the End User and the Database
  15. 15. DBMS Functions • Performs functions that guarantee integrity and consistency of data. – Data dictionary management • defines data elements and their relationships – Data storage management– Data storage management • stores data and related data entry forms, report definitions, etc. – Data transformation and presentation • translates logical requests into commands to physically locate and retrieve the requested data
  16. 16. DBMS Functions (continued) – Security management • enforces user security and data privacy within database – Multi-user access control– Multi-user access control • creates structures that allow multiple users to access the data – Backup and recovery management • provides backup and data recovery procedures
  17. 17. DBMS Functions (continued) – Data integrity management • promotes and enforces integrity rules to eliminate data integrity problems – Database access languages and application– Database access languages and application programming interfaces • provides data access through a query language – Database communication interfaces • allows database to accept end-user requests within a computer network environment