sol-99-00 - CIS209 WEST Exam paper 1999/2000 Marian Ursu...

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CIS209 – WEST – Exam paper 1999/2000 Marian Ursu Part A Attempt three of the following four problems. Total marks = 9; all problems carry equal marks . Problem 1 . Do database systems provide physical program–data independence? Explain why? [3] Solution: yes the conceptual level shields the application programs from the physical details of the data structures; as long as the logical structure of data remains the same, which is reflected in the conceptual level, the changes in the physical structure are invisible to the application programs. Correct answer: 3 marks. Problem 2 . Define the concept of “database schema”. Describe the types of schemas that exist in a database complying with the three level ANSI/SPARC architecture. [3] Solution database schema = the description of the database external schemas; one for each view conceptual schema; describes the structure of the overall data (from all the views) at the logical level; internal schema; describes the physical representation of data. Correct answer: 3 marks. Problem 3 . Define the notion of scalar data value. Give examples. Can the same data type be considered atomic by one designer in one application but non-atomic by another designer in another application (in your explanation, use the data type ADDRESS)? [3] Solution smallest semantic unit of data name, dob, first-name, last-name … yes; it depends of the level of granularity that is needed in the database application; Correct answer: 3 marks. 1
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CIS209 – WEST – Exam paper 1999/2000 Marian Ursu Problem 4 . What is a data dictionary (also called a system catalogue)? Describe some of the information that it can contain. How is this information organised in a relational database? Give an example. [3] Solution data dictionary – description of the data in the database schemas, mappings, integrity rules, security rules, views, statistical information … in form of relations the relation containing information about all the relations in the database Relations(Relation- name, Degree, cardinality, …) Correct answer: 3 marks. TOTAL 9 marks. 2
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CIS209 – WEST – Exam paper 1999/2000 Marian Ursu Part B Attempt two of the following three problems Total marks = 60; all problems carry equal marks. Problem 1 . Total marks: [30] a) Create a conceptual data model – ER diagram – for the Video Club of Silversmiths College described below. [10] b) If your solution contains multi-valued or composite attributes, many-to-many relationships or relationships with attributes, transform it into an equivalent one that does not contain these aspects. State any further assumptions you make that differ from the ones explicitly made in the text. [10] c) Transform the ER diagram into a relational model, specifying the primary, alternate (if any) and foreign keys. [10] The Information Services of Silversmiths College have decided to create a Video Club for both students and staff. The members of this club will be allowed to either borrow videos for home or
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This note was uploaded on 05/13/2010 for the course COMPRO CS401 taught by Professor Just during the Spring '10 term at Maharishi.

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sol-99-00 - CIS209 WEST Exam paper 1999/2000 Marian Ursu...

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