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Understanding about Object Relation Mapper(ORM)

What is ORM? Why we use ORM?
ORM is an Object Relation Mapper. The ORM is used to mapping between database layer to our Object Oriented code that is represent the database in our applications.

The Entity Framework and NHibernate are ORM tools.

LINQ is a ORM? No, LINQ is not an ORM. The LINQ is Language Integrated Query and used as query layer in our applications.

We can say that LINQ is a new query language that can be used to write the query using different types of sources.

The Object Relation Mapper(ORM) tools are
1.      Entity Framework and
2.      NHibernate

For example

using (dbDataContext database = new dbDataContext())
{
    var orders = from order in database.Orders
                  where order.ordernumber == "ord110xuz"
                  select new
                  {
                      order.ProductName,
                      order.UnitPrice
                  };

    foreach (var myorder in orders)
    {
       //TODO: as per you.
    }
}
You can use below link for more detail

https://weblogs.asp.net/dixin/understanding-linq-to-sql-1-object-relational-mapping
http://stackoverflow.com/questions/193781/is-linq-an-object-relational-mapper


Thank you!

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