Understanding Database Concepts

What is a view in a database?

• A view is a backup of the database.

• A view is a physical table stored in the database.

• A view is a type of database index.

• A view is a virtual table based on a SELECT query.

How do you modify a database schema?

• You modify a database schema by deleting all existing tables.

• You can only modify a database schema through a graphical user interface.

• You modify a database schema by creating and executing migration scripts.

• You modify a database schema by copying the entire database to a new server.

What are joined relations in SQL?

• Joined relations are only possible with three or more tables.

• Joined relations are a type of database index.

• Joined relations refer to the physical storage of tables in SQL.

• Joined relations in SQL are the result of combining rows from multiple tables based on a related column.

Define Data Definition Language (DDL).

• Data Definition Language (DDL) is a method for analyzing data trends.

• Data Definition Language (DDL) is a programming language for creating applications.

• Data Definition Language (DDL) is a language used to define the structure of a database.

• Data Definition Language (DDL) is used for querying data in a database.

What is the purpose of triggers in a database?

• The purpose of triggers in a database is to automatically execute actions in response to specific events on a table or view.

• To define the structure of a database table.

• To create backups of the database automatically.

• To store data in a more efficient way.

How can views improve data security?

• Views can delete sensitive data automatically.

• Views enhance performance but do not affect security.

• Views allow unrestricted access to all data.

• Views improve data security by restricting access to sensitive data and enforcing data access policies.

Explain the difference between inner join and outer join.

• Inner join includes NULLs for non-matches; outer join does not.

• Inner join returns matched rows; outer join returns all rows with NULLs for non-matches.

• Inner join returns all rows; outer join returns only matched rows.

• Inner join is used for filtering data; outer join is used for aggregating data.

What SQL command is used to create a trigger?

• ADD TRIGGER

• INSERT TRIGGER

• MODIFY TRIGGER

• CREATE TRIGGER

How do you drop a view in SQL?

• DROP TABLE view_name;

• DROP VIEW view_name;

• DELETE VIEW view_name;

• REMOVE VIEW view_name;

What are the advantages of using triggers in database management?

• Triggers are only useful for large databases

• Triggers slow down database performance

• Advantages of using triggers include automated enforcement of business rules, improved data integrity, automatic logging of changes, and reduced application complexity.

• Triggers can replace all application logic