Understanding Database Concepts

What is the purpose of normalization in a relational database?

• To increase data redundancy and decrease data integrity.

• To simplify the database structure by merging tables.

• To enhance the performance of database queries without changing data structure.

• The purpose of normalization is to reduce data redundancy and improve data integrity in a relational database.

Define the first normal form (1NF).

• A table is in first normal form (1NF) if it contains repeating groups of data.

• A table is in first normal form (1NF) if it has multiple primary keys.

• A table is in first normal form (1NF) if it allows null values in all columns.

• A table is in first normal form (1NF) if it has a primary key, contains only atomic values, and each record is unique.

What is an entity in an Entity-Relationship model?

• An entity is a distinct object or thing in the real world that can be identified.

• An entity is a process that occurs in the system.

• An entity is a collection of attributes that describe a thing.

• An entity is a type of relationship between two objects.

How do relationships between entities get represented in ER models?

• Relationships are shown as squares with dotted lines between entities.

• Relationships are represented by circles connecting entities with arrows.

• Relationships are depicted using colors to differentiate entities.

• Relationships are represented by diamonds connecting entities with lines.

What is the main goal of database access control?

• To increase data redundancy and accessibility.

• To allow unrestricted access to all users.

• To eliminate the need for data backups.

• To ensure authorized access and protect data integrity and confidentiality.

Explain the concept of primary key in a database.

• A primary key is used to store large amounts of data in a single record.

• A primary key is a unique identifier for a record in a database table, ensuring uniqueness and non-null values.

• A primary key is an optional field that can be left blank.

• A primary key can be duplicated across records in a table.

What are foreign keys used for in relational databases?

• Foreign keys are used to create indexes for faster data retrieval.

• Foreign keys are used to enforce referential integrity between tables in relational databases.

• Foreign keys are used to store large amounts of data in a single table.

• Foreign keys are used to define the primary key of a table.

Describe what data integrity constraints are.

• Data integrity constraints are methods for increasing database storage capacity.

• Data integrity constraints are optional rules that can be ignored in a database.

• Data integrity constraints are rules that enforce the accuracy and consistency of data in a database.

• Data integrity constraints are guidelines for user interface design.

What is the difference between entity integrity and referential integrity?

• Referential integrity is about the uniqueness of foreign keys.

• Entity integrity is concerned with the relationships between different databases.

• Entity integrity focuses on the uniqueness and validity of primary keys, while referential integrity focuses on the consistency of relationships between tables.

• Entity integrity ensures data is stored in a single table only.

How can data redundancy be managed in a database?

• Regularly delete old data to free up space.

• Normalize the database and use foreign keys to link related data.

• Ignore duplicate entries and proceed with data entry.

• Use a single table for all data storage.