Exam_04 - EXAMINATIONS 2004 MID-YEAR COMP442 COMP 442...

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COMP442 continued 1 EXAMINATIONS 2004 COMP442 MID-YEAR COMP 442 Issues in Database and Information Systems Time Allowed: 3 Hours (180 minutes) Instructions: Attempt all questions. Make sure your answers are clear and to the point. Non-programmable calculators without full alphabetic keys are permitted. Non-electronic foreign language dictionaries are permitted. No reference material is allowed. There are 180 possible marks on the exam. Answer in the appropriate heavily outlined boxes or follow the instructions given in the questions. Question Topic Marks 1 OLAP Specific Queries [28 marks] 2 Pivoting [17 marks] 3 WINDOW [20 marks] 4 CUBE Lattice and Attribute Hierarchy [10 marks] 5 Query Rewriting [15 marks] 6 XML Schema [20 marks] 7 XML DTD [10 marks] 8 Mapping Relational Schema to XML DTD [20 marks] 9 XML Normal Form [30 marks] 10 XML Functional Dependencies [10 marks]
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COMP442 continued 2 Question 1 OLAP Specific Queries [28 marks] Given the words/phrases below: a) Roll–up h) Slice b) Pivoting i) Drill–down c) Dice j) Ranking d) CUBE k) ROLLUP e) TopN l) Histolic Aggregate f) WINDOW m) Distributive Aggregate g) Algebraic Aggregate n) OPTIMIZE FOR N ROWS Select the word or phrase from the list above that best matches each of the following descriptions. Write the letter of your answer for each description in the answer box. Each word/phrase should be used only once. I. An OLAP query that takes the current aggregation level of a Data Warehouse fact table and performs a further aggregation using either an attribute hierarchy or even drops some dimensions. II. An OLAP query that looks for more detailed data using an attribute hierarchy of one (or more) dimension, or even uses operational data. III. An OLAP query that is performed on a fact table using a project operation on a proper subset of dimensions and a select operation with equality condition. IV. An OLAP query that is performed on a fact table using a project operation on a proper subset of dimensions and a select operation with range condition. V. An OLAP query that is performed on a fact table by selecting two dimensions, aggregating the measure, and representing the aggregated measure in a grid having two selected dimensions as coordinates. VI. An OLAP query that returns only the top N items within each partition. VII. An extension of SQL telling the SQL processor to stop displaying rows of a partition after first N rows. VIII. An aggregate function whose intermediate results can be used to directly compute coarser aggregates. IX. An extension to the SQL GROUP BY clause that computes aggregates of ( n + 1 ) sublists of a grouping list with attributes. It starts with the whole list and then successively omits the last attribute in the current sublist. X. An aggregate function whose intermediate result can be hardly used to
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Exam_04 - EXAMINATIONS 2004 MID-YEAR COMP442 COMP 442...

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