Data Modeling-- LESSON ONE

[OracleMan]

Asslmu Alekum ,

Lesson 1:-
Introduction to Entities, Attributes, relationships


In this lesson we will take inturduction about

1-Entities
2-Attributes
3-Relationships

Firstly: - Entity
- Is Something of significance to the business about which data must be known
- Is Category of things that are important for a business , about which information must be kept.
- Is Something you can make a list of , and which is important for the business
- Is Class or type of things
- Is Named things, usually noun

There are many entities: ( Table )
1- Tangible, like PERSON, PRODUCT.
2- Non-tangible, like REQUIRED SKILL LEVEL
3- An event, like ELECTION


Secondly- Attribute ( column )
- represent something of significance to the business
- is a single valued property detail of an entity
- is a specific piece of information that:
- Describes
- Quantifies
- Qualifies
- Classifies
- Specifies an entity


Thirdly – Relationships
- represent something of significance to the business
- Express how entities are mutually related
- Always exist between two entities ( or one entity twice )
- Are named at both ends

[braveheart]

بداية ممتازة OracleMan

جزاك الله خير

[trust_words]

thx man, keep going ,and god pless u oracleman