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Study Guide Chapter Six (A114 & I111 Fall 2003)



True/False
Indicate whether the sentence or statement is true or false.
 

1. 

A user view is the set of requirements that is necessary to support the operations of a particular database user.
 

2. 

A design that supports all the user views is called a constructive design.
 

3. 

The first step in creating a user view is to represent the user view as a collection of tables.
 

4. 

After representing the user view as a collection of tables, the next steps in creating a view is to normalize the tables and identify all the keys.
 

5. 

In representing a user view as a collection of tables, the first item is to determine the entities involved and create a separate column for each.
 

6. 

In determining the primary key for each table, add one or more columns to the table for this key.
 

7. 

The primary key is a unique identifier.
 

8. 

When determining the properties for each entity, these properties will become the rows for the table.
 

9. 

There are several basic relationships: one-to-one, one-to-many, and many-to-many.
 

10. 

In a one-to-many relationship, the primary key of the "many" table becomes the foreign key of the "one" table.
 

11. 

A many-to-many relationship is created by creating a new table whose primary key is the combination of primary keys of the original table.
 

12. 

After establishing the relationships among the entities, the next step is to normalize the table(s).
 

13. 

When normalizing the tables, it is best to make them second normal form.
 

14. 

An alternate key is a column or collection of columns that could have been chosen as a primary key, but was not.
 

15. 

A foreign key is a column or collection of columns in one table that is required to match the value of the primary key for some row in another table, or be null.
 

16. 

The concept or property of using a foreign key is called referential integrity.
 

17. 

DBDM allows you to represent tables with standard notation and to add additional features capable of representing additional information.
 

18. 

DBDL allows you to represent alternate keys by using the abbreviation AK, secondary keys by using the abbreviation SK, and foreign keys by using the abbreviation FK.
 

19. 

A popular type of diagram that visually represents the structure of a database is the B-C diagram.
 

20. 

In an entity-relationship diagram, rectangles represent entities.
 

21. 

When you have completed the mapping and diagrams for the user views, you can merge these into one design.  You can do this by combining tables that have the same primary key into one table.
 

22. 

When creating user views, the new table will not contain all the columns from the combined tables.
 

23. 

When creating user views, after merging tables if the new design is not in third normal form, then it should be converted to second normal form before proceeding with the design specifications.
 

24. 

To transform each user view into DBDL, examine the requirements and create the necessary entities, keys, and relationships.
 

25. 

A relationship that is necessary for identification is called an identifying relationship.
 

26. 

In an E-R diagram, a dashed line represents an identifying relationship and a solid line represents a nonidentifying relationship.
 

27. 

When creating an E-R diagram, the “one” and "n" represent a one-to-one relationship.
 

28. 

A diamond shape within a rectangle indicates a composite entity in an E-R diagram.
 

29. 

The use of an "m" and an "n" in an E-R diagram indicates a many-to-many relationship.
 

30. 

Cardinality is the number of items that must be included in a relationship.
 

Modified True/False
Indicate whether the sentence or statement is true or false.  If false, change the identified word or phrase to make the sentence or statement true.
 

31. 

A DBMS should enforce restrictions.  When it cannot, it is up to either the user or the administrator.

 

32. 

The diamond shape in an E-R diagram represents the relationship between the entities.

 

33. 

A diamond within a rectangle represents a(n) composite entity.

 

34. 

Another way to indicate a one-to-many relationship is to place a crow's foot at the "one" end of the relationship.

 

35. 

A(n) top-down design methodology is where specific user requirements are synthesized into a design.

 

36. 

A design methodology that begins with a general database design and then repeatedly refines the model is known as a(n) top-down methodology.

 

37. 

A(n) survey form is a good way to obtain the required information from users.

 

38. 

Attribute information records the name, description, and any synonyms for an entity.

 

39. 

Use entity information to list the name, description, and physical characteristics about each column.

 

40. 

The survey should contain information about functional dependencies concerning any dependencies that exist among the columns.

 

41. 

A description of how updates to the database will occur, or how reports will be produced is known as processing information.

 

42. 

When obtaining information from an existing document, the first step is to identify and list all columns.

 
 
chsix1_files/i0450000.jpg
 

43. 

Please refer to the above figure. There is a(n) one-to-many relationship between the Customer table and the Rep table.

 
 
chsix1_files/i0470000.jpg
 

44. 

Please refer to the above figure.  Solution 2 illustrates a one-to-one relationship between the Customer table and the Rep table.  Assuming that any alternate key restrictions are removed, this relationship can be converted to a(n) many-to-many relationship.

 
 
chsix1_files/i0490000.jpg
 

45. 

Please refer to the above figure.  We see that the one table actually involves three entities.  This type of relationship is called a(n) one-to-many-to-one relationship.

 

46. 

The crucial issue in making the determination between a single many-to-many-to-many relationship and two (or three) many-to-many-to-many relationships is the independence.

 

47. 

A null actually represents the absence of a value in a(n) record.

 

48. 

Nulls are used when a value is inapplicable or unknown.

 
 
chsix1_files/i0540000.jpg
 

49. 

Please refer to the above figure.  The primary key of the Sales table is the RepNum, CustomerNum, and PartNum.

 



 
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