Data Modeling is a visualization tool, That helps in understanding the logical link between different entities which is going to interact with the system.Data Modeling on Database management system are divided in to two major types.Advantage of Data modeling of Database management system is it makes easy to understand the Database management system as well as clears the using and operating mechanism of Database management system.
Data Modeling generally uses 3 major Components Entity , Attributes and Relation.
Entity : The Entity is Group of Data. Object (group of same characteristics) entity must be generally a noun wheres relation must be Verb.For example a in a DBMS of school Data of group of student or teacher can be considered A Entity Because they resembles group having same .Entity is placed in Rectangular box on Data Modeling as shown in Figure.
Attributes : The property of defined Entity is called Attribute For example an ID card number can be a Attribute of An Entity Student. Similarly sex of an Student can also be attribute type where Boy or girl is an Attribute instance.Attributes are always Put on Oval Box as shown in figure.Attributes can be further classified in to
- Single Valued Attribute
- Double Valued Attribute
- Derived Attribute
- Composite Attribute
In Above Picture Age is a Derived attribute because it can be Derived From Date of Birth data so it doesn’t have to be actually entered. Hobbies are Double Valued Attributes because hobbies can be more then one of each Entity.Name can be break in to First name , Last name and Middle Name which Creates a Composite Attributes as shown in picture.
Relation : Relation is shown in Diamond Symbol. The relation is defined Between two or more entities.For example a Manager can handle different Departments. Above picture Describes all types of relationship.One to many , Many to many and Many to one Relation is Visible on embedded Picture. Relation on Data modeling are subdivided in to
- One to one
- One to many
- Many to one
- many to many
Types of Data Modeling
- Structured Data Modeling
- Object oriented Data Modeling
Structured Data modeling
Structured Data Modeling subdivided in to 4 subgroups
- ERD (Entity relationship Diagram)
- Relational Model
- DFD (Data flow
- Decision table
Object oriented Data modeling
Object Oriented Data modeling Consists of only one type called Unified Modeling Language which is combined effort of 3 Scientists Grady booch , Ivar jacobson & James rumbaugh.
- UML (Unified Modeling Language )
We will Cover Each and every Data modeling types (ERD, DFD , UML etc) on Further post on details with example