Database Normalization PT 1

What is a primary key in a database?

• A unique identifier for each record in a table

• A common identifier shared by multiple records

• The last record added to the table

• A random number assigned to each record

Explain the concept of a foreign key.

• A foreign key is a column or a set of columns in a table that references the primary key of another table.

• A foreign key is a key that is used to unlock a foreign language database.

• A foreign key is a key used to access a database from a different country.

• A foreign key is a key that is not allowed to be used in a database.

What is a composite key and when is it used?

• A composite key is used for sorting data in a table

• A composite key is never used in database tables

• A single column that uniquely identifies a row in a table

• A combination of two or more columns that uniquely identify a row in a table

Why is it important to have a primary key in a database?

• To increase the risk of data duplication and inconsistency

• To confuse the users and make it difficult to retrieve data

• To make the database slower and less efficient

• To uniquely identify each record in a table and ensure data integrity.

Which of the following is NOT a characteristic of a primary key in a relational database?

• A) It must contain unique values.

• B) It ensures data integrity within the table.

• C) It can have repeating values within the field.

• D) It serves as a unique identifier for each record.

Which side of the relationship typically holds the foreign key in a one-to-many relationship?

• A) The "one" side

• B) The "many" side

• C) Both sides equally

• D) It depends on the specific database implementation

Duplicate data often results in loss of data integrity because:

• A. Data formats may be inconsistent
• B. Data values may not agree
• Neither A & B
• Both A & B

Consider attributes ID, CITY, and NAME. Which one if this can be considered as a primary key?

• NAME
• ID
• CITY
• ID, NAME

which one of the following cannot be taken as a primary key?

• ID
• RegistrationNo
• DepartmentID
• Street

What is an atomic field?

• A field that contains multiple items of data

• A field that is repeated

• A field that contains only one item of data