DBMS Concepts

What is the Entity-Relationship Model used for in DBMS?

• It is used for creating animations.

• It is used for creating tables.

• It is used for predicting the primary key

• It is used for designing the database schema.

What are the basic components of an ER diagram?

• constraints

• keys

• tables

• entities, attributes, relationships

What is the purpose of SQL Queries in a database?

• To create schema

• To send emails from the database

• To retrieve, insert, update, or delete data in a database.

• To create animations in the database

Give an example of a SELECT query in SQL.

• SELECT * FROM database_name;

• SELECT * WHERE column_name = value;

• SELECT * FROM table;

• SELECT * FROM table_name;

Explain the concept of primary key in a database.

• A primary key is a secondary identifier for each record in a table.

• A primary key in a database is a unique identifier for each record in a table.

• A primary key can have duplicate values in a table.

• A primary key is used to store non-unique values in a database.

What are the different levels of data abstraction in DBMS?

• Data Layer, Schema Layer, and Query Layer

• Physical Layer, Logical Layer, and Virtual Layer

• Storage Layer, Schema Layer, and Presentation Layer

• Physical Level, Logical Level, and View Level

Define the term 'Schema' in the context of databases.

• A schema is a type of database software

• Schema refers to the physical storage of data in a database

• A schema in databases is a collection of metadata that defines the structure of the database.

• Schema is a term used to describe the process of querying a database

Explain the concept of a relational schema.

• A relational schema is a type of programming language used to query databases

• A relational schema is a blueprint that defines the structure of a database, including tables, columns, keys, and relationships between tables.

• A relational schema is a graphical representation of data in a database

• A relational schema is a physical storage unit for database records

What is the importance of data independence in DBMS?

• Data independence in DBMS is irrelevant and unnecessary

• Data independence in DBMS is important as it allows changes in the physical storage structure or access methods to be made without affecting the application programs.

• Data independence in DBMS only benefits the database administrators

• Data independence in DBMS leads to slower query processing

How does a foreign key differ from a primary key?

• A foreign key can have duplicate values, while a primary key cannot.

• A foreign key is used to establish relationships between tables, while a primary key uniquely identifies records within a table.

• A foreign key is always an integer, while a primary key can be any data type.

• A foreign key is used to uniquely identify records within a table, while a primary key establishes relationships between tables.