Understanding Data Models

What is a relational data model?

• A relational data model is a method for storing data in a single large file.

• A relational data model is a way to visualize data using graphs and charts.

• A relational data model is a way to structure data using tables that are related to each other.

• A relational data model is a programming language for database management.

Name three characteristics of relational data models.

• Data is organized in hierarchical structures.

• Data is stored in a single file.

• Relationships are defined by primary keys only.

• 1. Data is organized in tables (relations). 2. Relationships are established using foreign keys. 3. Data integrity is maintained through constraints.

What is an entity in an entity-relationship diagram?

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

• An entity is a graphical representation of data flow.

• An entity is a specific attribute of a real-world object.

• An entity is a real-world object or concept in an entity-relationship diagram.

Define the term 'attribute' in the context of data models.

• An attribute is a synonym for a data model.

• An attribute is a method used to manipulate data.

• An attribute is a property or characteristic of an entity in a data model.

• An attribute is a type of data model.

What is the purpose of a primary key in a relational database?

• To group related records together in a table.

• To store large amounts of data efficiently.

• To define the relationships between different tables.

• The purpose of a primary key in a relational database is to uniquely identify each record in a table.

Explain the difference between a one-to-one and a one-to-many relationship.

• A one-to-one relationship allows multiple matches for each record, while a one-to-many relationship has a single match.

• A one-to-one relationship has a single match for each record, while a one-to-many relationship allows multiple matches for a single record.

• A one-to-one relationship can only exist in databases, while a one-to-many relationship can exist in spreadsheets.

• A one-to-one relationship is used for grouping data, while a one-to-many relationship is for sorting data.

What does normalization mean in database design?

• Normalization is the process of combining multiple databases into one.

• Normalization refers to the method of encrypting data for security purposes.

• Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity.

• Normalization is the technique of backing up data to prevent loss.

List the main components of an entity-relationship diagram.

• Classes, Methods, Objects, Inheritance

• Tables, Rows, Columns, Keys

• Nodes, Edges, Weights, Paths

• Entities, Attributes, Relationships, Cardinalities

What is a foreign key and how is it used?

• A foreign key is a field that stores data unrelated to other tables.

• A foreign key is a field that links two tables by referencing the primary key of another table.

• A foreign key is a type of primary key used in a single table.

• A foreign key is a unique identifier for a record in the same table.

Describe the concept of data integrity in relational databases.

• Data integrity ensures the accuracy and consistency of data in relational databases through constraints and rules.

• Data integrity is concerned with the physical storage of data on disk.

• Data integrity refers to the speed of data retrieval in databases.

• Data integrity is the process of backing up data regularly.