exam1 - cs 6400

March 26, 2018 | Author: Nina Pham | Category: Conceptual Model, Data Model, Databases, Scientific Modeling, Information Management


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CS 6400 – Exam 1 – Spring 20171. Which of the following are considered representational data models? A) Hierarchical data model B) Relational data model C) Network data model D) All of the above E) None of the above 2.How is a surrogate used in a DBMS? A) To uniquely identify something B) To speed up access to data in a separate table C) To generate a custom view D) To identify a column in a table E) None of the above 3.Which of the following is NOT a reason to use a DBMS? A) Need to share data with multiple users B) Need to support serious real-time access requirements C) Need persistence of storage and centralized control D) All of the above are reasons to use a DBMS E) None of the above are reasons to use a DBMS 4. If the data stored in your DBMS has no redundancy, you are also guaranteed that you: A) have consistency B) have completeness C) have improved performance D) have all of the above E) have none of the above 5. Which of the following statements is true? A) End users of a database must know details about the storage structures used by the database system B) Application programmers are responsible for the physical design of the database C) The database administrator is responsible for authorizing access to the database D) All of the above are true E) None of the above are true 6. In a database system, a NULL value indicates: A) The value exists, but we do not know it. B) The value does not exist C) The value is not applicable D) All of the above E) None of the above if you choose it you will miss the question. entity names must be: A) Nouns B) Verbs C) Unique D) Monotonic E) None of the above 12. E) None of the above 11.7. According to the 3-level ANSI/SPARC database schema. If we change the conceptual schema in a database without affecting the external schema. Which of the following is more difficult for a DBMS to provide? A) Logical data independence B) Physical data independence C) They are equally difficult to provide D) This answer is obviously not the correct one. The first commercial EER database system was sold by: A) Oracle B) Microsoft C) IBM D) SAP E) None of the above . a virtual table (view) is part of the: A) internal schema B) external schema C) conceptual schema D) metadata E) None of the above 9. we change which of the following? A) the database schema B) the database state C) the database intension D) All of the above E) None of the above 8. Every time we delete a record from a database. then we refer to this as which of the following? A) Information encapsulation B) Logical data independence C) External view updatability D) Impedance mismatch E) None of the above 10. In an EER diagram. Which of the following statements is true? A) A weak entity type never has a partial key B) A weak entity type does not have a key made up entirely of attributes of its own C) A weak entity type always has a total participation constraint with respect to its identifying relationship D) Both (B) and (C) E) None of the above N 1 ManagementCompany Property Manages PName MName 15. then which of the following statements are true? A) There may be 33 instances of the Appears entity type B) There may be no instances of the Appears entity type C) There may be 103 instances of the Appears entity type . The EER model does NOT provide support for: A) classification B) aggregation C) generalization D) A & C E) None of the above 14. then which of the following statements are true? A) We must have 15 instances of the Property entity type B) We must have 15 instances of the ManagementCompany entity type C) We must have at least 1 instance of the ManagementCompany entity type D) Both (A) and (C) E) None of the above M N Car Appears Show 16. if we have 3 instances of the Car relationship type.13. Considering the EER diagram above. Considering the EER diagram above. if we have 15 instances of the Manages relationship type. and 10 instances of the Show type. Considering the <same duplicate> EER diagram above. Location D) Number. which of the following statements is true? . Considering the <same duplicate> EER diagram above. is it possible for two different Doctors to have the same set of values for the phone attribute? A) Yes B) No C) Unable to say from the diagram D) All of the above E) None of the above 18. What are the attributes that uniquely identify a room entity? A) Number B) Number. Considering the EER diagram above. Name C) Number.D) All of the above E) None of the above SSN Doctor Phone 17. In E) None of the above 20. Name. what type of attribute is Phone in our EER diagram? A) Derived attribute B) Multi-valued attribute C) Composite attribute D) All of the above E) None of the above N Room 1 In Building Location Number Name 19. Considering the EER diagram above. if there are 100 instances of Employee and 10 instances of Manager. Considering the EER diagram above. then how many total instances of Person could exist? A) 0 B) 10 C) 100 D) 110 E) None of the above 22. duplicate> EER diagram above. In the relational data model (not EER diagrams) how many different types of data structures exist? A) 1 B) 2 C) 3 . if there are 100 instances of Employee and 10 instances of Manager. Considering the <same. then how many instances of ManagedBy must exist? A) 0 B) 10 C) 100 D) 110 E) None of the above 23.A) A building must have multiple rooms B) A building must have at least one room C) A room must be in a single building D) Both (A) and (C) E) None of the above First Last Phone Name Person Hours O Employee Manager N 1 ManagedBy 21. where E1 represents a subclass of E2 .D) More than 3 E) None of the above 24. and E2 represents a subclass of E3 in a generalization/specialization relationship in the EER model. Which of the following statements is/are true? A) E 1 inherits attributes only from E2 B) E 1 inherits attributes from E2 as well as from E3 C) E 3 inherits attributes from both E1 and E2 D) All of the above are true E) None of the above . Which of the following statements is true? A) The value of a derived attribute may be determined from related entities B) The key of an entity type can not be a composite attribute C) A weak entity type cannot have a multivalued attribute D) All of the above are true E) None of the above 25. E2 and E3 . Consider entity types E1.
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