Database Design and Development in SQL Server – SQL Server Tutorial

DATABASE DESIGN in SQL Server:-

Steps followed in database development:

• Analysis
• Design
• Development
• Implementation
• Maintenance.

1. Db designed by “DB Designer(or) DB Architect”
2. The DB designer designed the  db by using two techniques,

                       (i) ER model:  Top-down  Approach

                       (ii) Normalization: Bottom up    Approach

1. DB developed by “DB Developer”
2. The developer the will develop the database by using “RDBMS TOOL” i:e sql server (or) oracle. 

ER MODEL in SQL Server   :–

1. ER stands for “entity relationship” model
2. It is a “Graphical  representation of data”.
3. The  diff. element of ER model

•       Entities
•       Entity sets
•       Attributes
•       Relationships

ENTITY in SQL Server with Example:–  

• It is an object.

Ex: Employee,customer,bank A/c,course etc.

ENTITY SETS in ER Diagram with Example:–

• Collection of entities that share common properties is called “Entity Sets”. 

Example —

 

Symbol: rectangle represents the entity set.

    Example:  Employee

Examples of ATTRIBUTES  in Database:–

• Attributes one the properties of entity.

Example:–

          Empid       ename      job     sal

These are all properties of employee.

• Attributes are indicated by symbol is “Oval or Ellipse”.

RELATIONSHIPS in SQL Server    :–

• A relationship is a association b/w entities of entity sets.

 

• The relationship is indicated by symbol  is “dimension”

Types of Relationships in SQl Server :–

•  1 to 1
• 1 to many
• Many to Many

  

• ER  model can be used to at “Design part”

Difference Between ER model and Relational Model

ER Model                                               Relational Model

Entity sets                                         Here,entity sets are converted to “Tables”

Attributes                                           “Fields”

Relationships                                     “Foreign keys”