McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Computer Science Engineering (CSE) , Bachelor of Science in Computer Science FY (BSc CS) , Bachelor of Science in Computer Science SY (BSc CS) , Bachelor of Science in Information Technology SY (BSc IT) , Bachelor of Computer Applications (BCA) .
Chapters
| 151. |
The term is used to refer to a row. |
| A. | attribute |
| B. | tuple |
| C. | field |
| D. | instance |
| Answer» B. tuple | |
| 152. |
For each attribute of a relation, there is a set of permitted values, called the of that attribute. |
| A. | domain |
| B. | relation |
| C. | set |
| D. | schema |
| Answer» A. domain | |
| 153. |
A domain is atomic if elements of the domain are considered to be units. |
| A. | different |
| B. | indivisbile |
| C. | constant |
| D. | divisible |
| Answer» B. indivisbile | |
| 154. |
Which one of the following is a set of one or more attributes taken collectively to uniquely identify a record? |
| A. | candidate key |
| B. | sub key |
| C. | super key |
| D. | foreign key |
| Answer» C. super key | |
| 155. |
Consider attributes ID, CITY and NAME. Which one of this can be considered as a super key? |
| A. | name |
| B. | id |
| C. | city |
| D. | city, id |
| Answer» B. id | |
| 156. |
The subset of a super key is a candidate key under what condition? |
| A. | no proper subset is a super key |
| B. | all subsets are super keys |
| C. | subset is a super key |
| D. | each subset is a super key |
| Answer» A. no proper subset is a super key | |
| 157. |
A is a property of the entire relation, rather than of the individual tuples in which each tuple is unique. |
| A. | rows |
| B. | key |
| C. | attribute |
| D. | fields |
| Answer» B. key | |
| 158. |
Which one of the following attribute can be taken as a primary key? |
| A. | name |
| B. | street |
| C. | id |
| D. | department |
| Answer» C. id | |
| 159. |
Which one of the following cannot be taken as a primary key? |
| A. | id |
| B. | register number |
| C. | dept_id |
| D. | street |
| Answer» D. street | |
| 160. |
An attribute in a relation is a foreign key if the key from one relation is used as an attribute in that relation. |
| A. | candidate |
| B. | primary |
| C. | super |
| D. | sub |
| Answer» B. primary | |
| 161. |
The relation with the attribute which is the primary key is referenced in another relation. The relation which has the attribute as a primary key is called |
| A. | referential relation |
| B. | referencing relation |
| C. | referenced relation |
| D. | referred relation |
| Answer» C. referenced relation | |
| 162. |
The is the one in which the primary key of one relation is used as a normal attribute in another relation. |
| A. | referential relation |
| B. | referencing relation |
| C. | referenced relation |
| D. | referred relation |
| Answer» C. referenced relation | |
| 163. |
A integrity constraint requires that the values appearing in specified attributes of any tuple in the referencing relation also appear in specified attributes of at least one tuple in the referenced relation. |
| A. | referential |
| B. | referencing |
| C. | specific |
| D. | primary |
| Answer» A. referential | |
| 164. |
The operation allows the combining of two relations by merging pairs of tuples, one from each relation, into a single tuple. |
| A. | select |
| B. | join |
| C. | union |
| D. | intersection |
| Answer» B. join | |
| 165. |
The result which operation contains all pairs of tuples from the two relations, regardless of whether their attribute values match. |
| A. | join |
| B. | cartesian product |
| C. | intersection |
| D. | set difference |
| Answer» B. cartesian product | |
| 166. |
The operation performs a set union of two “similarly structured” tables |
| A. | union |
| B. | join |
| C. | product |
| D. | intersect |
| Answer» A. union | |
| 167. |
The most commonly used operation in relational algebra for projecting a set of tuple from a relation is |
| A. | join |
| B. | projection |
| C. | select |
| D. | union |
| Answer» C. select | |
| 168. |
The operator takes the results of two queries and returns only rows that appear in both result sets. |
| A. | union |
| B. | intersect |
| C. | difference |
| D. | projection |
| Answer» B. intersect | |
| 169. |
A is a pictorial depiction of the schema of a database that shows the relations in the database, their attributes, and primary keys and foreign keys. |
| A. | schema diagram |
| B. | relational algebra |
| C. | database diagram |
| D. | schema flow |
| Answer» A. schema diagram | |
| 170. |
The provides a set of operations that take one or more relations as input and return a relation as an output. |
| A. | schematic representation |
| B. | relational algebra |
| C. | scheme diagram |
| D. | relation flow |
| Answer» B. relational algebra | |
| 171. |
Which one of the following provides the ability to query information from the database and to insert tuples into, delete tuples from, and modify tuples in the database? |
| A. | dml(data manipulation langauge) |
| B. | ddl(data definition langauge) |
| C. | query |
| D. | relational schema |
| Answer» A. dml(data manipulation langauge) | |
| 172. |
To remove a relation from an SQL database, we use the command. |
| A. | delete |
| B. | purge |
| C. | remove |
| D. | drop table |
| Answer» D. drop table | |
| 173. |
Updates that violate are disallowed. |
| A. | integrity constraints |
| B. | transaction control |
| C. | authorization |
| D. | ddl constraints |
| Answer» A. integrity constraints | |
| 174. |
The clause allows us to select only those rows in the result relation of the clause that satisfy a specified predicate. |
| A. | where, from |
| B. | from, select |
| C. | select, from |
| D. | from, where |
| Answer» A. where, from | |
| 175. |
The clause is used to list the attributes desired in the result of a query. |
| A. | where |
| B. | select |
| C. | from |
| D. | distinct |
| Answer» B. select | |
| 176. |
Which of the following statements contains an error? |
| A. | select * from emp where empid = 10003; |
| B. | select empid from emp where empid = 10006; |
| C. | select empid from emp; |
| D. | select empid where empid = 1009 and lastname = ‘geller’; |
| Answer» D. select empid where empid = 1009 and lastname = ‘geller’; | |
| 177. |
In SQL the spaces at the end of the string are removed by function. |
| A. | upper |
| B. | string |
| C. | trim |
| D. | lower |
| Answer» C. trim | |
| 178. |
The union operation is represented by |
| A. | ∩ |
| B. | u |
| C. | – |
| D. | * |
| Answer» B. u | |
| 179. |
The intersection operator is used to get the tuples. |
| A. | different |
| B. | common |
| C. | all |
| D. | repeating |
| Answer» B. common | |
| 180. |
If we want to retain all duplicates, we must write in place of union. |
| A. | union all |
| B. | union some |
| C. | intersect all |
| D. | intersect some |
| Answer» A. union all | |
| 181. |
The number of attributes in relation is called as its |
| A. | cardinality |
| B. | degree |
| C. | tuples |
| D. | entity |
| Answer» B. degree | |
| 182. |
clause is an additional filter that is applied to the result. |
| A. | select |
| B. | group-by |
| C. | having |
| D. | order by |
| Answer» C. having | |
| 183. |
joins are SQL server default |
| A. | outer |
| B. | inner |
| C. | equi |
| D. | none of the mentioned |
| Answer» B. inner | |
| 184. |
The is essentially used to search for patterns in target string. |
| A. | like predicate |
| B. | null predicate |
| C. | in predicate |
| D. | out predicate |
| Answer» A. like predicate | |
| 185. |
A indicates an absent value that may exist but be unknown or that may not exist at all. |
| A. | empty tuple |
| B. | new value |
| C. | null value |
| D. | old value |
| Answer» C. null value | |
| 186. |
If the attribute phone number is included in the relation all the values need not be entered into the phone number column. This type of entry is given as |
| A. | 0 |
| B. | – |
| C. | null |
| D. | empty space |
| Answer» C. null | |
| 187. |
The predicate in a where clause can involve Boolean operations such as and. The result of true and unknown is false and unknown is while unknown and unknown is |
| A. | unknown, unknown, false |
| B. | true, false, unknown |
| C. | true, unknown, unknown |
| D. | unknown, false, unknown |
| Answer» D. unknown, false, unknown | |
| 188. |
Using the clause retains only one copy of such identical tuples. |
| A. | null |
| B. | unique |
| C. | not null |
| D. | distinct |
| Answer» D. distinct | |
| 189. |
The primary key must be |
| A. | unique |
| B. | not null |
| C. | both unique and not null |
| D. | either unique or not null |
| Answer» C. both unique and not null | |
| 190. |
The result of unknown is unknown. |
| A. | xor |
| B. | or |
| C. | and |
| D. | not |
| Answer» D. not | |
| 191. |
Aggregate functions are functions that take a as input and return a single value. |
| A. | collection of values |
| B. | single value |
| C. | aggregate value |
| D. | both collection of values & single value |
| Answer» A. collection of values | |
| 192. |
A Boolean data type that can take values true, false, and |
| A. | 1 |
| B. | 0 |
| C. | null |
| D. | unknown |
| Answer» D. unknown | |
| 193. |
The connective tests for set membership, where the set is a collection of values produced by a select clause. The connective tests for the absence of set membership. |
| A. | or, in |
| B. | not in, in |
| C. | in, not in |
| D. | in, or |
| Answer» C. in, not in | |
| 194. |
The phrase “greater than at least one” is represented in SQL by |
| A. | < all |
| B. | < some |
| C. | > all |
| D. | > some |
| Answer» D. > some | |
| 195. |
SQL applies predicates in the clause after groups have been formed, so aggregate functions may be used. |
| A. | group by |
| B. | with |
| C. | where |
| D. | having |
| Answer» B. with | |
| 196. |
The keyword is used to access attributes of preceding tables or subqueries in the from clause. |
| A. | in |
| B. | lateral |
| C. | having |
| D. | with |
| Answer» B. lateral | |
| 197. |
Which of the following creates a temporary relation for the query on which it is defined? |
| A. | with |
| B. | from |
| C. | where |
| D. | select |
| Answer» A. with | |
| 198. |
Subqueries cannot: |
| A. | use group by or group functions |
| B. | retrieve data from a table different from the one in the outer query |
| C. | join tables |
| D. | appear in select, update, delete, insert statements. |
| Answer» C. join tables | |
| 199. |
Which of the following is not an aggregate function? |
| A. | avg |
| B. | sum |
| C. | with |
| D. | min |
| Answer» C. with | |
| 200. |
The EXISTS keyword will be true if: |
| A. | any row in the subquery meets the condition only |
| B. | all rows in the subquery fail the condition only |
| C. | both of these two conditions are met |
| D. | neither of these two conditions is met |
| Answer» A. any row in the subquery meets the condition only | |
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