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Q.21 Which of the following is NOT a basic/fundamental Relational Algebra operation?
Set Difference
Cartesian product
Rename
Join
Explanation
Join is considered a derived or non-fundamental operator in relational algebra because it can be performed using a combination of Cartesian Product and Selection. Set Difference, Cartesian Product, and Rename are all fundamental operations.
Q.22 How is specialization denoted in an ER diagram?
Triangle labeled IS A
Rectangle labeled IS A
Rectangle labeled HAS A
Triangle labeled HAS A
Explanation
In Entity-Relationship diagrams, Specialization (and Generalization) is represented using a triangle component labeled ‘IS A’, which connects the high-level entity to the low-level entities.
Q.23 Which of the following is an open-source DBMS?
MySQL
SQL Server
Microsoft Access
Oracle
Explanation
MySQL is one of the most popular open-source relational database management systems. SQL Server, Oracle, and MS Access are proprietary/commercial products developed by Microsoft and Oracle.
Q.24 Which SQL keyword is used to remove the duplication of rows from the result set?
DELETE
SELECT
DISTINCT
UNIQUE
Explanation
The DISTINCT keyword is used in a SELECT statement to eliminate duplicate rows from the results, ensuring that only unique values are returned.
Q.25 What is the highest level in a hierarchy of data organization?
Data record
Data field
Database
None of these
Explanation
In the data hierarchy, the order from lowest to highest is: Bit, Byte, Field, Record, File, and finally, Database, which is the collection of related files/tables.
Q.27 Which command allows the users to change multiple data fields in existing records?
Modify
Look up
Update
Change
Explanation
The SQL UPDATE command is part of the Data Manipulation Language (DML) and is used to modify the existing data within a table.
Q.28 Which of the following languages is used to define integrity constraints?
DCL
DML
DDL
TCL
Explanation
DDL (Data Definition Language) is used to define the database structure, including tables, schemas, and integrity constraints like Primary Key or Foreign Key.
Q.29 In an ER diagram, attributes are represented as:
Rectangle
Square
Ellipse
Diamond
Explanation
In Entity-Relationship modeling, Ellipses (or Ovals) are used to represent attributes, Rectangles represent entities, and Diamonds represent relationships.
Q.30 The architecture of a database system is typically viewed as having:
Two levels
Four levels
Three levels
One level
Explanation
The ANSI-SPARC database architecture consists of three levels: the External level (user views), the Conceptual level (logical structure), and the Internal level (physical storage).
Q.31 In the relational model, relations are termed as?
Tuples
Attributes
Table
Row
Explanation
In relational database theory, a ‘Relation’ is the mathematical term for what is commonly known in practice as a ‘Table’.
Q.32 A Cartesian product in relational algebra is a:
Unary Operator
Binary operator
Ternary operator
None of these
Explanation
The Cartesian product (X) is a binary operator because it requires two input relations to produce a resulting relation containing all possible combinations of tuples.
Q.33 SQL stands for?
Structured Query Language
Sequential Query Language
Structured Question Language
None of these
Explanation
SQL stands for Structured Query Language, which is the standard language for dealing with Relational Databases.
Q.34 The following are components of a database EXCEPT?
User data
Meta data
Indexes
Explanation
User data, metadata (data about data), and indexes are internal components of a database. Reports are external outputs or tools used to present data, not a core storage component of the database itself.
Q.35 A set of possible data values for an attribute is called a?
Attribute
Degree
Tuple
Domain
Explanation
A Domain is the set of all unique values permitted for an attribute in a database column.
Q.36 Which of the following database objects does not physically exist?
Base table
Index
View
None of these
Explanation
A View is a virtual table based on the result-set of an SQL statement. It does not store data physically; instead, it provides a way to look at data stored in base tables.
Q.37 Cross product is a?
Unary operator
Ternary operator
Binary operator
None of the above
Explanation
A Cross product (also known as Cartesian product) is a binary operator because it operates on two relations.
Q.38 In an E-R diagram, a relationship is represented by a?
Ellipse
Dashed line
Rectangle
Diamond
Explanation
A Diamond-shaped box is used in E-R diagrams to represent the relationship between two or more entities.
Q.39 Which SQL clause/command is used when you need to modify the structure of a table, such as deleting a column?
UPDATE
DROP
ALTER
DELETE
Explanation
To delete a column, you use the ‘ALTER TABLE’ command combined with ‘DROP COLUMN’. ‘DELETE’ is used only for removing rows/records.
Q.40 A table joined with itself is called a?
Join
Self join
Outer join
Equi join
Explanation
A Self-join is a regular join, but the table is joined with itself. This is often used to query hierarchical data within the same table.