IB Computer Science Topic A.2.12 Entity-relationship Diagrams Revision Notes (SL/HL)

IB Computer Science Topic A.2.12 Entity-relationship Diagrams Revision Notes (SL/HL) | RevisionDojo

Entity-Relationship Diagrams (ERDs) are visual tools used to model the relationships between entities in a database.
They help in designing databases by illustrating how data is connected and organized.

Note

ERDs are essential for understanding the structure of a database before implementation.

Key Components of ERDs

Entities

Entities are objects or concepts that have data stored about them.
Each entity is represented as a rectangle in an ERD.

Attributes

Attributes are properties or characteristics of an entity.
They are represented as ovals connected to their entity.

Example

Student: StudentID, Name, Age
Course: CourseID, Title, Credits

Primary Keys

A primary key is a unique identifier for each record in an entity.
It ensures that each record can be uniquely identified.

Example

StudentID can be a primary key for the Student entity.
CourseID can be a primary key for the Course entity.

Foreign Keys

A foreign key is an attribute that creates a link between two entities.

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(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

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Note

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Excepteur sint occaecat cupidatat non proident

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Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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Entity-Relationship Diagrams (ERDs) are visual tools used to model the relationships between entities in a database.
They help in designing databases by illustrating how data is connected and organized.

Note

ERDs are essential for understanding the structure of a database before implementation.

Key Components of ERDs

Entities

Entities are objects or concepts that have data stored about them.
Each entity is represented as a rectangle in an ERD.

Attributes

Attributes are properties or characteristics of an entity.
They are represented as ovals connected to their entity.

Example

Student: StudentID, Name, Age
Course: CourseID, Title, Credits

Primary Keys

A primary key is a unique identifier for each record in an entity.
It ensures that each record can be uniquely identified.

Example

StudentID can be a primary key for the Student entity.
CourseID can be a primary key for the Course entity.

Foreign Keys

A foreign key is an attribute that creates a link between two entities.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

1. System fundamentals2 subtopics

2. Computer organization1 subtopic

3. Networks1 subtopic

4. Computational thinking, problem-solving and programming3 subtopics

5. Abstract data structures (HL)1 subtopic

6. Resource management (HL)1 subtopic

7. Control (HL)1 subtopic

A. Databases4 subtopics

B. Modelling and simulation4 subtopics

C. Web science6 subtopics

D. Object-oriented programming (OOP)4 subtopics

IB Computer Science A.2.12 Entity-relationship Diagrams Notes

1. System fundamentals2 subtopics

2. Computer organization1 subtopic

3. Networks1 subtopic

4. Computational thinking, problem-solving and programming3 subtopics

5. Abstract data structures (HL)1 subtopic

6. Resource management (HL)1 subtopic

7. Control (HL)1 subtopic

A. Databases4 subtopics

B. Modelling and simulation4 subtopics

C. Web science6 subtopics

D. Object-oriented programming (OOP)4 subtopics

Key Components of ERDs

Entities

Attributes

Primary Keys

Foreign Keys

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Key Components of ERDs

Entities

Attributes

Primary Keys

Foreign Keys

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account