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13 Cards in this Set
- Front
- Back
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1. Which of the following accesses a database in terms of a database model?
A. Application software B. Database management system C. Actual database |
A. Application software. |
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2. Which of the following describes only the portion of a database available to a particular user? A. Database model B. Schema C. Subschema D. DBMS |
C. Subschema. |
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3. Which of the following relational operations combine data from more than one relation? A. SELECT B. PROJECT C. JOIN |
C. JOIN. |
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4. Which of the following relational operations extracts entire columns from a relation? A. SELECT B. PROJECT C. JOIN |
B. PROJECT. |
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5. Which of the following relational operations extracts entire rows from a relation?
A. SELECT B. PROJECT C. JOIN |
A. SELECT. |
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6. Which of the following relational operations is performed by the SQL statement below? select A, B, C from X A. SELECT B. PROJECT C. JOIN |
B. PROJECT. |
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7. Given the relation X below X: A B C 2 5 7 3 3 3 4 3 2 5 2 8 what value will be extracted by the following query? TEMP <- SELECT from X where B > C RESULT <- PROJECT A from TEMP A. 2 B. 3 C. 4 D. 5 |
C. 4. |
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8. Given the relation X below X: A B C 2 5 7 3 3 3 4 4 2 5 2 8 what value will be retrieved by the following query? TEMP <- SELECT from X where B = C RESULT <- PROJECT B from TEMP A. 2 B. 3 C. 4 D. 5 |
B. 3. |
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9. Given the relation below X: A B C 2 5 7 3 3 6 4 4 2 5 2 2 what values will be retrieved by the following SQL statement? select A, B from X where X.B = X.C A. 2,5 B. 3,6 C. 2,2 D. 5,2 |
D. 5,2. |
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10. Given the two relations X and Y below X: A B Y: C D 7 s t 3 2 z r 2 what value would be retrieved by executing the following SQL statement? select Y.C from X, Y where X.A < Y.D A. s B. z C. t D. r |
C. t.???? |
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11. Which of the following is not a potential problem caused by multiple transactions manipulating a database at the same time?
A. Lost update problem B. Clustering C. Deadlock D. Incorrect summary problem |
B. Clustering. |
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12. Which of the following features within a DBMS is not provided to maintain database integrity? A. Concurrent transaction processing B. Log C. Locking protocol D. Commit points |
A. Concurrent transaction processing. |
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13. Which of the following data mining techniques would be applied when trying to identify traits that characterize the citizens of a democracy whofail to vote? A. Class description B. Class discrimination C. Cluster analysis D. Association analysis |
D. Association analysis
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