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1 | |
Which of the following statements does not apply to relational databases? |
| | A) | Relational databases are simple to understand |
| | B) | Tables are one of the basic components of relational databases |
| | C) | Relational databases have a strong procedural orientation |
| | D) | Relational databases have a strong mathematical foundation |
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2 | |
In the relational database terminology, a table is synonymous with: |
| | A) | A column |
| | B) | A row |
| | C) | An attribute |
| | D) | A relation |
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3 | |
A null value indicates: |
| | A) | A numeric value with value 0 |
| | B) | The absence of a value |
| | C) | A very small value |
| | D) | An erroneous value |
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4 | |
When the referential integrity rule is enforced, which one is usually not a valid action in response to the deletion of a row that contains a primary key value referenced elsewhere? |
| | A) | Do not allow the deletion |
| | B) | Accept the deletion without any other action |
| | C) | Delete the related rows |
| | D) | Set the foreign keys of related rows to null |
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5 | |
A relational algebra operator applied to tables Ex and Dx produces the following result:
 <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::::/sites/dl/free/0072942207/90831/2_30.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (21.0K)</a>]]>
That operator is: |
| | A) | An outer join operator |
| | B) | The project operator |
| | C) | The extended cross product operator |
| | D) | The natural join operator |
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6 | |
A relational algebra operator applied to tables Dx and Ex produces the following result:
 <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::::/sites/dl/free/0072942207/90831/2_31.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (10.0K)</a>]]>
That operator is: |
| | A) | An outer join operator |
| | B) | The project operator |
| | C) | The extended cross product operator |
| | D) | The natural join operator |
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7 | |
A relational algebra operator applied to tables Dx and Ex produces the following result:
 <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::::/sites/dl/free/0072942207/90831/2_32.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (12.0K)</a>]]>
That operator is: |
| | A) | An outer join operator |
| | B) | The project operator |
| | C) | The extended cross product operator |
| | D) | The natural join operator |
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8 | |
When an equi-join is performed on a table of N rows and a table of M rows, the resulting table has the following number of rows: |
| | A) | M |
| | B) | N |
| | C) | The smaller of M or N |
| | D) | A number in the range 0 to M*N |
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9 | |
The Union of a table of N rows and of a table of M rows (M<=N) has the following number of rows: |
| | A) | M+N |
| | B) | A number in the range N to M+N |
| | C) | N |
| | D) | A number in the range 0 to M |
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10 | |
The following pair of tables is union compatible: |
| | A) | Dept1, Dept4 |
| | B) | Dept1, Dept3 |
| | C) | Dept3, Dept4 |
| | D) | All of the above |
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