Relational Data Model

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Relational Data Model by Mind Map: Relational Data Model

1. Table

1.1. Each table row represent a single entity occurence within the entity set

1.2. Each table column represent an attribute and each column has a distinct name

1.3. Each rows/column intersection represent a single data value

1.4. A table is perceived as a two-dimensional structure composed of rows and column

2. Integrity Rules

2.1. Entity integrity

2.1.1. primary keys

2.2. Referential integrity

2.2.1. Foreign Keys

3. Definition

3.1. a digital database whose organization is based on the relational model of data

3.2. proposed by E. F. Codd in 1970

3.3. The various software systems used to maintain relational databases are known as a relational database management system

3.4. all data is represented in terms of tuples, grouped into relations

4. Keys

4.1. Primary Key (PK)

4.1.1. cannot contain null values

4.2. Foreign key (FK)

4.2.1. column(s) whose values must match the values in a candidate key of another table

4.3. Candidate Key

4.3.1. minimal superkey

4.4. Superkey

4.4.1. Composed of more than one attribute

4.5. Composite Key

4.5.1. A multiple-attribute key

4.6. Nullls

4.6.1. special value meaning value unknown or inapplicable

5. Relationship

5.1. 1:1 Relationshop

5.1.1. primary keys

5.1.1.1. Action Item

5.1.1.2. Action Item

5.1.1.3. Action Item

5.2. M:N Relationship