This presantaion is all about ORM and how to implement the idea of ORM using C# created by Imal hasaranga perera for the microsoft monthly meeting november (sri lanka)

1. ORM in C#
Using Visual Paradigm
By : Imal Hasaranga Perera

2. Agenda
What is ORM?
Introduction to VP
Using VP to Generate RDB
Generating C# .NET Persistent Library
Demo of how to use Persistent library
Q&A

3. What is ORM ???
Object Relational Mapping, A way of getting object-oriented
languages and relational databases to work together
Object world Relational world
User
Stu Mapping
A…
B..

4. The Object-Relational Impedance
Mismatch
'Object-Relational Impedance Mismatch' is just a fancy way of
saying that object models and relational models do not work
very well together. RDBMSs represent data in a tabular
format , whereas object-oriented languages, such as Java, C#
represent it as an interconnected graph of objects. Loading
and storing graphs of objects using a tabular relational
database exposes us to 5 mismatch problems

5. The Object-Relational Impedance
Mismatch
1) Granularity
2) Inheritance
3) Identity
4) Associations
5) Data Types

6. 1. Granularity
Sometimes you will have an object model which has more classes
than the number of corresponding tables in the database
public class Teacher{
}
public class School{
}

7. 2. Inheritance
Inheritance is a natural paradigm in object-oriented
programming languages. However, RDBMSs do not define
anything similar to Inheritance
User_main
Inheritance
Student Teacher

8. 3. Identity
A RDBMS defines exactly one notion of 'sameness'
Teacher_id = 2233
Thread 1 Teacher
Thread 2 Teacher

9. 4. Associations
Associations are represented as unidirectional references in
Object Oriented languages whereas RDBMSs use the notion of
foreign keys. If you need bidirectional relationships in C#, you
must define the association twice
Class user_main {
Teacher teacher;
}
Class Teacher {
}

10. 5. Data Types
When we consider about data types there a mismatches,
simply String might have limited size than a varchar data type
String Varchar(150)
Mismatches Between Date and time in the object world and
the relational world

11. Reason for using ORM??
Speeds-up Development - eliminates the need for repetitive
SQL code.
Reduces Development Time.
Reduces Development Costs. User nuser = UserFactory.createUser();
Overcomes vendor specific SQL differences - the ORM
nuser.Fname = t1.Text;
knows how to write vendor specific SQLt2.Text; don't have
nuser.Lname =
so you
nuser.Type = t3.Text;
to. nuser.Save();
Rich query capability. ORM tools provide an object oriented
t.commit();
query language.

12. Lets Get Started With
Visual Paradigm

13. Relational database
Example ER Diagram Created by Using VP

14. Code Generating Process in VP
Generate C# project
using Visual paradigm

16. Thank You