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TCA

TCA. Section A : 40% Case study Create ER Level 2 and attributes Section B : 60% 30 Questions 2 marks correct answer -1 mark deducted for an incorrect answer. TCA. January Monday 13 th 1 - 2.30 N133A. Modules Topics. Data Modelling the ER Model SQL File Organisation DBMS

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TCA

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  1. TCA • Section A : 40% • Case study • Create ER Level 2 and attributes • Section B : 60% • 30 Questions • 2 marks correct answer • -1 mark deducted for an incorrect answer

  2. TCA • January Monday 13th 1 - 2.30 N133A

  3. Modules Topics • Data Modelling the ER Model • SQL • File Organisation • DBMS • Relational Algebra • Relational Optimization • Integrity & Security • Concurrency / Recovery • Networked & Distributed Systems

  4. Data Modelling the ER Model • Identify Entity's from a case study • Draw a ER Diagram level 1 and 2 & showing all relationships

  5. SQL • SQL explanation

  6. File Organisation • Blocking • How is it used • Why is it used • Calculation on disk utilisation • File access • Type of indexes • Dense vs. non-dense

  7. File Organisation • Direct access methods • Hashing • Collisions, handling collisions • Dynamic data structures • Linked lists • Inverted lists • Deletion, insertion & updating files

  8. DBMS • Maintenance of physical data structures (files, indexes,etc) • Languages for storage, retrieval and update of the data (3GL’s, 4GL’s) • Facilities for ensuring data integrity and security • Support for multi-user access • Backup and recovery measures

  9. DBMS • Facilities for maintenance of meta-data (data dictionary or system catalogue) • Data independence (logical view) • Tools for the database administrator • User Interface • Database Engine • Data Dictionary

  10. Relational Algebra • Compares strategies (Number of Recs) • SELECT (restrict a(R)) • picks out particular Rows • PROJECT a,b(R) • picks out particular Columns • JOIN R |X| S • Draw Query Execution Plan • Choice of order, smaller temp tables

  11. Relational Optimization • Reasons for being • Process involved • Steps involved, Interpretation, Execution • Position • Integrated in DBMS, Interactive SQL, reference to Data Dictionary • Types • Rule Based • Cost Based

  12. Security & Integrity • What are the issues surrounding security and integrity • What security issues exist that have to be resolved • What measures are used to ensure consistency of the database • Why do we implement these measures

  13. Concurrency and Recovery • Definitions • ACID properties of transactions • Need for Concurrency / Recovery • Lost update, Uncommitted Updates, Inconsistent Analysis • Crashes, Sabotage, Logical errors...

  14. Recovery uses LOG file • Format of LOG entry • Transaction record, Check points • Incremental Log • Deferred Updates • Immediate Updates

  15. Concurrency Techniques • Locks • Shared/Exclusive, Two phase locking • Problem of Deadlock • Timestamps • Compares timestamps of transactions • Problem late transactions • Optimistic • Used where few conflict expected

  16. Networked & Distributed Systems • What are distributed databases • In what kind of situation are they suitable • What advantages / disadvantages to they have over centralised systems • Problems that can arise due to the use of DDB

  17. Networked & Distributed Systems • Implementation issues • Concurrency • Replication • Query processing • Transparency • Fragmentation

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