MCQOPTIONS
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MCQOPTIONS
This section includes 15 Mcqs, each offering curated multiple-choice questions to sharpen your Rdbms knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
State true or false: If a relation consists of a foreign key, then it is called a referenced relation of the foreign key dependency. |
| A. | True |
| B. | False |
| Answer» C. | |
| 2. |
Choose the option that correctly explains in words, the function of the following relational algebra expressionσyear≥2009 (book ⋈ borrow) |
| A. | Selects all tuples from the Cartesian product of book and borrow |
| B. | Selects all the tuples from the natural join of book and borrow wherever the year is lesser than 2009 |
| C. | Selects all the tuples from the natural join of book and student wherever the year is greater than or equal to 2009 |
| D. | Selects all tuples from the Cartesian product of book and borrow wherever the year is greater than or equal to 2009 |
| Answer» C. Selects all the tuples from the natural join of book and student wherever the year is greater than or equal to 2009 | |
| 3. |
Statement 1: A tuple is a row in a relation Statement 2: Existence of multiple foreign keys in a same relation is possible |
| A. | Both the statements are true |
| B. | Statement 1 is correct but Statement 2 is false |
| C. | Statement 1 is false but Statement 2 is correct |
| D. | Both the statements are false |
| Answer» B. Statement 1 is correct but Statement 2 is false | |
| 4. |
What does the “x” operator do in relational algebra? |
| A. | Output specified attributes from all rows of the input relation. Remove duplicate tuples from the output |
| B. | Output pairs of rows from the two input relations that have the same value on all attributes that have the same name |
| C. | Output all pairs of rows from the two input relations (regardless of whether or not they have the same values on common attributes) |
| D. | Returns the rows of the input relation that satisfy the predicate |
| Answer» D. Returns the rows of the input relation that satisfy the predicate | |
| 5. |
What action does ⋈ operator perform in relational algebra |
| A. | Output specified attributes from all rows of the input relation and remove duplicate tuples from the output |
| B. | Outputs pairs of rows from the two input relations that have the same value on all attributes that have the same name |
| C. | Output all pairs of rows from the two input relations (regardless of whether or not they have the same values on common attributes) |
| D. | Return rows of the input relation that satisfy the predicate |
| Answer» B. Outputs pairs of rows from the two input relations that have the same value on all attributes that have the same name | |
| 6. |
STATE_TRUE_OR_FALSE:_IF_A_RELATION_CONSISTS_OF_A_FOREIGN_KEY,_THEN_IT_IS_CALLED_A_REFERENCED_RELATION_OF_THE_FOREIGN_KEY_DEPENDENCY.?$ |
| A. | True |
| B. | False |
| Answer» C. | |
| 7. |
CHOOSE_THE_OPTION_THAT_CORRECTLY_EXPLAINS_IN_WORDS,_THE_FUNCTION_OF_THE_FOLLOWING_RELATIONAL_ALGEBRA_EXPRESSION?$ |
| A. | |
| B. | Selects all tuples from the Cartesian product of book and borrow |
| C. | Selects all the tuples from the natural join of book and borrow wherever the year is lesser than 2009 |
| D. | Selects all the tuples from the natural join of book and student wherever the year is greater than or equal to 2009 |
| Answer» C. Selects all the tuples from the natural join of book and borrow wherever the year is lesser than 2009 | |
| 8. |
Statement 1: A tuple is a row in a relatio? |
| A. | |
| B. | Both the statements are true |
| C. | Statement 1 is correct but Statement 2 is false |
| Answer» B. Both the statements are true | |
| 9. |
What is the method of specifying a primary key in a schema description? |
| A. | By writing it in bold letters |
| B. | By underlining it using a dashed line |
| C. | By writing it in capital letters |
| D. | By underlining it using a bold line |
| Answer» E. | |
| 10. |
An attribute is a __________ in a relation. |
| A. | Row |
| B. | Column |
| C. | Value |
| D. | Tuple |
| Answer» C. Value | |
| 11. |
What does the “x” operator do in relational algebra?$ |
| A. | Output specified attributes from all rows of the input relation. Remove duplicate tuples from the output |
| B. | Output pairs of rows from the two input relations that have the same value on all attributes that have the same name |
| C. | Output all pairs of rows from the two input relations (regardless of whether or not they have the same values on common attributes) |
| D. | Returns the rows of the input relation that satisfy the predicate |
| Answer» D. Returns the rows of the input relation that satisfy the predicate | |
| 12. |
What action does ‚ãà operator perform in relational algebra$ |
| A. | Output specified attributes from all rows of the input relation and remove duplicate tuples from the output |
| B. | Outputs pairs of rows from the two input relations that have the same value on all attributes that have the same name |
| C. | Output all pairs of rows from the two input relations (regardless of whether or not they have the same values on common attributes) |
| D. | Return rows of the input relation that satisfy the predicate |
| Answer» B. Outputs pairs of rows from the two input relations that have the same value on all attributes that have the same name | |
| 13. |
What is a foreign key? |
| A. | A foreign key is a primary key of a relation which is an attribute in another relation |
| B. | A foreign key is a superkey of a relation which is an attribute in more than one other relations |
| C. | A foreign key is an attribute of a relation that is a primary key of another relation |
| D. | A foreign key is the primary key of a relation that does not occur anywhere else in the schema |
| Answer» D. A foreign key is the primary key of a relation that does not occur anywhere else in the schema | |
| 14. |
What is an Instance of a Database? |
| A. | The logical design of the database system |
| B. | The entire set of attributes of the Database put together in a single relation |
| C. | The state of the database system at any given point of time |
| D. | The initial values inserted into the Database immediately after its creation |
| Answer» D. The initial values inserted into the Database immediately after its creation | |
| 15. |
Choose the correct statement regarding superkeys |
| A. | A superkey is an attribute or a group of multiple attributes that can uniquely identify a tuple |
| B. | A superkey is a tuple or a set of multiple tuples that can uniquely identify an attribute |
| C. | Every superkey is a candidate key |
| D. | A superkey is an attribute or a set of attributes that distinguish the relation from other relations |
| Answer» B. A superkey is a tuple or a set of multiple tuples that can uniquely identify an attribute | |