Test: Database Management System - 2 - Computer Science Engineering (CSE) MCQ

Every weak entity must be linked to an identifying entity; in other words, the existence of the weak entity set is contingent on the presence of the identifying entity set. The weak entity set that the identifying entity set identifies is said to be owned by the identifying entity set. Owner entity set is another name for it.

Non-Procedural Languages are Domain relational calculus and Tuple relational calculus. Relational algebra is a procedural language that takes input in the form of relation and output generated is also a relation.

If and only if, for each of its non-trivial multivalued dependencies X \twoheadrightarrow Y, a table is in 4NF. X is a superkey—that is, X is either a candidate key or a superset thereof.

The term cardinality refers to the uniqueness of data values included in a single column (attribute) of a table in SQL (Structured Query Language).

Any property that does not occur in the group by clause must only appear in an aggregate function if it also appears in the select clause; otherwise, the query is considered incorrect.

The correct answer is:

4. Having

Explanation:

• The 'HAVING' clause is used in SQL to apply conditions (predicates) to groups after they have been created with the 'GROUP BY' clause. Unlike the 'WHERE' clause, which filters rows before grouping, the 'HAVING' clause filters groups based on aggregate functions (such as 'SUM', 'COUNT', 'AVG', etc.).

Using the two relationships mother and father gives us a record of a child’s mother, even if we don’t know who the father is; if the ternary connection parent is used, a null value is necessary. In this scenario, binary relationship sets are preferred.

Pointers are used to access data with great speed and accuracy. Consistency is maintained using locks.

In the command the P gives condition to delete a particular tuple.

Concatenation in DBMS is used to join two or more table fields of the same table or different tables. Example inst sec and student sec.

DDLs are used to define schema and table characters and consist of commands that help in modifying. DML performs the change in the values of the relation.

The term "DDL" stands for Data Definition Language, used to perform all other essential tasks such as deleting relation and related schemas in defining the structure relation.

Correct option is 2. SELECT name, course_id FROM instructor NATURAL JOIN teaches;

This query uses the NATURAL JOIN clause to join the "instructor" and "teaches" tables based on the common column "instructor_ID=teaches_ID".

We can understand the "one to many" relationship as a teacher who may have more than one class to attend.

To sort the salary from highest to lowest amount and display the employee's name alphabetically, one can use the "Desc and Asc" in the above-given Query.