IB Computer Science Topic A.2.13 Designing Relational Databases Revision Notes (SL/HL)

IB Computer Science Topic A.2.13 Designing Relational Databases Revision Notes (SL/HL) | RevisionDojo

Definition

Relational Databases

A collection of data items with predefined relationships between them, organized as a set of tables with columns and rows.

Relational databases are the backbone of modern data management systems.
They enable efficient storage, retrieval, and manipulation of structured data.

Key Components of Relational Databases

Tables:
1. The fundamental building blocks of a relational database, where data is stored in rows and columns.
2. Each table represents an entity (e.g., Students, Courses) and contains attributes (e.g., Name, Age).
Primary Keys: Unique identifiers for each record in a table, ensuring data integrity.
Foreign Keys: Attributes that establish relationships between tables by referencing primary keys in other tables.
Relationships: Connections between tables, such as one-to-many, many-to-many, or one-to-one.

Normalization

Definition

Normalization

A process used to organize data in a database to reduce redundancy and improve data integrity.

As discussed before, there are three forms:
1. First Normal Form (1NF): Ensures that each attribute contains only atomic (indivisible) values.
2. Second Normal Form (2NF): Requires that all non-key attributes are fully functionally dependent on the primary key.
3. Third Normal Form (3NF): Ensures that no transitive dependencies exist, meaning non-key attributes depend only on the primary key.

Example

Consider a table with student data:

StudentID	Name	Course1	Course2
1	Alice	Math	Science
2	Bob	Math	English

This table violates 1NF because it contains repeating groups (Course1, Course2).

To normalize it, we create two tables:
- Students Table:

StudentID	Name
1	Alice
2	Bob

Courses Table:

StudentID	Course
1	Math
1	Science
2	Math
2	English

Now, each attribute contains atomic values, and the data is organized efficiently.

Designing a Relational Database

Step 1: Identify Entities and Attributes

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Definition

Paywall

(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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Tip

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Definition

Relational Databases

A collection of data items with predefined relationships between them, organized as a set of tables with columns and rows.

Relational databases are the backbone of modern data management systems.
They enable efficient storage, retrieval, and manipulation of structured data.

Key Components of Relational Databases

Tables:
1. The fundamental building blocks of a relational database, where data is stored in rows and columns.
2. Each table represents an entity (e.g., Students, Courses) and contains attributes (e.g., Name, Age).
Primary Keys: Unique identifiers for each record in a table, ensuring data integrity.
Foreign Keys: Attributes that establish relationships between tables by referencing primary keys in other tables.
Relationships: Connections between tables, such as one-to-many, many-to-many, or one-to-one.

Normalization

Definition

Normalization

A process used to organize data in a database to reduce redundancy and improve data integrity.

As discussed before, there are three forms:
1. First Normal Form (1NF): Ensures that each attribute contains only atomic (indivisible) values.
2. Second Normal Form (2NF): Requires that all non-key attributes are fully functionally dependent on the primary key.
3. Third Normal Form (3NF): Ensures that no transitive dependencies exist, meaning non-key attributes depend only on the primary key.

Example

Consider a table with student data:

StudentID	Name	Course1	Course2
1	Alice	Math	Science
2	Bob	Math	English

This table violates 1NF because it contains repeating groups (Course1, Course2).

To normalize it, we create two tables:
- Students Table:

StudentID	Name
1	Alice
2	Bob

Courses Table:

StudentID	Course
1	Math
1	Science
2	Math
2	English

Now, each attribute contains atomic values, and the data is organized efficiently.

Designing a Relational Database

Step 1: Identify Entities and Attributes

Definition

Paywall

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

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Duis aute irure dolor in reprehenderit

Note

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Excepteur sint occaecat cupidatat non proident

Tip

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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.2.13 Designing Relational Databases 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 Relational Databases

Normalization

Designing a Relational Database

Step 1: Identify Entities and Attributes

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Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

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Key Components of Relational Databases

Normalization

Designing a Relational Database

Step 1: Identify Entities and Attributes

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