Database - The Relational Model and Normalizartion
Database - The Relational Model and Normalizartion
12. Which of the following is not a restriction for a table to be a relation?
- The cells of the table must contain a single value.
- All of the entries in any column must be of the same kind.
- The columns must be ordered.
- No two rows in a table may be identical.
13. For some relations, changing the data can have undesirable consequences called:
- referential integrity constraints.
- modification anomalies.
- normal forms.
- transitive dependencies.
14. A key:
- must always be composed of two or more columns.
- can only be one column.
- identifies a row.
- identifies a column.
15. An attribute is a(n):
- column of a table.
- two dimensional table.
- row of a table.
- key of a table.
16. A relation in this form is free of all modification anomalies.
- First normal form
- Second normal form
- Third normal form
- Domain/key normal form
17. If attributes A and B determine attribute C, then it is also true that:
- A ? C.
- B ? C.
- (A,B) is a composite determinant.
- C is a determinant.
18. A tuple is a(n):
- column of a table.
- two dimensional table.
- row of a table.
- key of a table
19. If attribute A determines both attributes B and C, then it is also true that:
- A ? B.
- B ? A.
- C ? A.
- (B,C) ? A.
20. One solution to the multivalued dependency constraint problem is to:
- split the relation into two relations, each with a single theme.
- change the theme.
- create a new theme.
- add a composite key.