Data Base Management System MCQs SET-1

When a primary key is defined, the DBMS automatically creates a unique index on that column to ensure data integrity and to speed up data retrieval operations.

Second Normal Form (2NF) is specifically concerned with removing partial functional dependencies, ensuring that all non-key attributes are fully functional dependent on the primary key.

Relational databases conceptually organize data into tables, which are essentially two-dimensional arrays consisting of rows and columns.

The conceptual view (or logical level) provides a complete description of the data stored in the database and the relationships between them for the entire community of users.

Aggregate functions perform a calculation on a set of values and return a single value. Count, Avg, and Max are aggregate functions, whereas 'Create' is a Data Definition Language (DDL) command.

DDL stands for Data Definition Language. It includes commands like CREATE, ALTER, and DROP, which are used to define or modify the structure of database objects.

ACID is an acronym for Atomicity, Consistency, Isolation, and Durability. These are a set of properties that guarantee that database transactions are processed reliably.

A database table can have only one primary key. However, this primary key can consist of a single column or multiple columns (which is then called a composite key).

In database modeling, attributes are the characteristics or properties that describe an entity (for example, 'Name' and 'Age' are attributes of a 'Student' entity).

Relational algebra is a procedural query language because it describes the steps or operations (like select, project, join) required to get the desired result from the database.

The ALTER statement is used to add, delete, or modify columns in an existing table, effectively changing the table's definition/structure.

The COUNT() function returns the number of rows that match a specified criterion or simply the number of non-null values in a specific column.

In Entity-Relationship (ER) diagrams, rectangles are used to represent entity sets, while ellipses represent attributes and diamonds represent relationships.

DML (Data Manipulation Language) is the component of SQL used for accessing and manipulating data, such as retrieving (SELECT), inserting, or updating records.

The degree of a relation is the total number of attributes (columns) it contains. The total number of tuples (rows) is called its cardinality.

Hierarchical, Relational, and Network are established database models. 'Transition' is not a recognized category of database architecture.

The SELECT statement is classified as DML (Data Manipulation Language) because it is used to retrieve and view data from the tables.

DDL stands for Data Definition Language, which is used to define the database schema and structure.

In the three-level architecture of a DBMS, the external level (or view level) is the one closest to the users as it describes only the part of the database relevant to a specific user.

SQL provides several comparison operators to filter data, including the equals sign (=), the LIKE operator for pattern matching, and the BETWEEN operator for range filtering.