Database Management: Many-to-Many Relationships and Constraints

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What is the characteristic of a many-to-many relationship between entities A and B?

An entity in A is associated with more than one entities in B and an entity in B is associated with more than one entities in A.

What is the primary purpose of constraints in a database?

To maintain the quality of information and ensure data integrity.

What is the function of a check constraint in a database?

To define a business rule on a column and limit data values to a specific set, range, or list of values.

What is an example of a many-to-many relationship?

A customer is connected with more than one loan using borrower and a loan is connected with more than one customer using borrower. Signup and view all the answers

What is the purpose of integrity constraints in a database?

To guard against accidental damage to the database and ensure data integrity. Signup and view all the answers

How many types of integrity constraints are mentioned in the text?

6 Signup and view all the answers

What is a strong entity in an ER diagram?

A strong entity is an entity type that has a key attribute and can be identified uniquely. Signup and view all the answers

How are the relationships of two strong entities represented in an ER diagram?

By a single diamond. Signup and view all the answers

What is a weak entity in an ER diagram?

A weak entity is an entity set that does not have sufficient attributes for unique identification of its records. Signup and view all the answers

How are weak entities represented in an ER diagram?

By a double rectangle. Signup and view all the answers

What is an attribute in an ER diagram?

An attribute is a property or detail about an entity. Signup and view all the answers

What is the purpose of a primary key in a strong entity?

To identify each entity uniquely. Signup and view all the answers

What is the range of values for the SPI column?

0 to 10 Signup and view all the answers

What is the purpose of the NOT NULL constraint in a database?

It ensures that a column does not allow null values. Signup and view all the answers

What is the main difference between a UNIQUE constraint and a PRIMARY KEY constraint?

A PRIMARY KEY constraint is a combination of UNIQUE and NOT NULL constraints. Signup and view all the answers

What is the purpose of a FOREIGN KEY constraint in a database?

It establishes a referential integrity constraint between two tables. Signup and view all the answers

What is the range of values for the Enrollment number column?

12345001 to 12346999 Signup and view all the answers

What is the purpose of the UNIQUE constraint in a database?

It ensures that a column or a group of columns have distinct values. Signup and view all the answers

What is the issue that arises when we delete an employee with ID 'E2' from the database?

The Civil department will also be deleted because there is only one record of Civil department. Signup and view all the answers

What happens when we update the department name from 'Computer' to 'IT' in the database?

One or more records will be updated, but not all. Signup and view all the answers

How can data redundancy be removed from a database?

With the help of normal forms. Signup and view all the answers

What is the purpose of normalizing a database?

To remove data redundancy. Signup and view all the answers

What happens to the Civil department when an employee with ID 'E2' is deleted?

The Civil department will also be deleted because there is only one record of Civil department. Signup and view all the answers

What is the advantage of using normal forms in a database?

It helps remove data redundancy. Signup and view all the answers

What is the main advantage of using Normal forms in a database?

Removing data redundancy Signup and view all the answers

What is the condition for a relation to be in 1NF?

Each cell of a table should contain a single value or all underlying domains contain atomic values. Signup and view all the answers

What is a composite attribute in a relation?

An attribute that can be further divided into sub-attributes. Signup and view all the answers

Why is it difficult to retrieve the list of customers living in 'Jamnagar' from the given table?

The address attribute is a composite attribute containing road name and city name in a single cell. Signup and view all the answers

What happens to the number of tables and complexity as we move from 1NF to 3NF?

The number of tables and complexity increases, but redundancy decreases. Signup and view all the answers

What is the main problem with the given 'Customer' relation?

It is not in 1NF because the address attribute is a composite attribute. Signup and view all the answers