Unit of work pattern is the concept to provide single transaction of multiple works(like insert, update, delete and so on.. ) of an entity as well as of multiple entities which has to be done into database in single go. If any one of the activities get failed then non of the activities will get executed in database, in short entire transaction will be roll backed.
Unit of Work design pattern does two important things: first it maintains in-memory updates and second it sends these in-memory updates as one transaction to the database.
So to achieve the above goals it goes through two steps:
See the below flow of transaction without unit of work and with unit of work
The way to implement this pattern is as :
create a interface to define database operations.
Step 2: Create Repository class
Implement operations defined in above IRepository interface. And create constructor to accept dbContext as parameter.
Step 3: Create Unit of Work class
Unit of work class has the responsibility to provide instance of dbContext to repository(shown as below).
Unit of work class has the three activities
Step 4: Access and implement unit of work in business logic
In below order class, instance of unit of work class is created to handle all type of communication with database. Here in AddOrder method two instances are created on for order and second for customer details. And both entity is saved into database as a single work unit.
Repository Pattern separates the data access logic and maps it to the entities in the business logic. It works with the domain entities and performs data access logic. In the Repository pattern, the domain entities, the data access logic and the business logic talk to each other using interfaces. It hides the details of data access from the business logic. In other words, business logic can access the data object without having knowledge of the underlying data access architecture. For example, in the Repository pattern, business logic is not aware whether the application is using LINQ to SQL or ADO.NET Entity Model ORM. In the future, underlying data sources or architecture can be changed without affecting the business logic.
There are various advantages of the Repository Pattern including:
Repository acts as a mediator between business logic and data source(database).
How to Implement Repository pattern in C#
The way to implement repository pattern in any application is as:Step 1 : Define interface
Its highly recommended that an architecture must create a generic repository interface only.
Step 2 : Create Repository
Implement the database operation defined in step 1(IRepository)
In above code EntityBase is a base class for all entities which has an ID property of type Int.
Step 2 : Access repository from business logic
To access repository from business logic, create an instance of repository in business logic and use it as per requirement.
Using below jquery code you can encode HTML
function htmlEncode(value){
//create a in-memory div, set it's inner text(which jQuery automatically encodes)
//then grab the encoded contents back out. The div never exists on the page.
return $('<div/>').text(value).html();
}
function htmlDecode(value){
return $('<div/>').html(value).text();
}
htmlEncode('<b>test</b>')
// result"<b>test</b>"