Differences between Linq to Sql and ADO.NET Entity
Framework?
Linq to sql is no support
for Conceptual modelà
Linq to Sql : no Conceputal Data model, no storage schema,
no mapping schema.(csdl).
Here
In case of LINQ to SQL-à
database objects are application classes so there is tightly coupling.
Between
LINQ to SQL -à
ORM model ---to application objects.
[emp(RDBMS)----à
dbo.emp];
Why because along with Particular schema-à dbml is generated.
Like
<Table Name="dbo.Categories" Member="Categories"> // 1.
<Type
Name="Category">
<Column
Name="CategoryID" Type="System.Int32" DbType="Int NOT NULL IDENTITY" IsPrimaryKey="true" IsDbGenerated="true" CanBeNull="false" />
<Column
Name="CategoryName" Type="System.String" DbType="NVarChar(15) NOT NULL" CanBeNull="false" />
<Association Name="Category_Product" Member="Products" ThisKey="CategoryID" OtherKey="CategoryID" Type="Product" /> // 2.
</Type>
</Table>
Every property is tightly coupled with particular table –linq
to sql.
[Table(Name="dbo. Categories ")]
public partial
class Customer
: INotifyPropertyChanging
{
private string _CustomerID;
[Column(Storage="_CustomerID", DbType="NChar(5)
NOT NULL", CanBeNull=false,
IsPrimaryKey=true)] // 3.
public string CustomerID
{
get
{
return this._CustomerID;
}
set
{
if ((this._CustomerID != value))
{
this.OnCustomerIDChanging(value);
this.SendPropertyChanging();
this._CustomerID
= value;
this.SendPropertyChanged("CustomerID");
this.OnCustomerIDChanged();
}
}
}
Linq to Sql
1. No Models support: single file only
<Table Name="dbo.Categories" Member="Categories">
<Type Name="Category">
<Column Name="CategoryID" Type="System.Int32" DbType="Int NOT NULL IDENTITY" IsPrimaryKey="true" IsDbGenerated="true" CanBeNull="false" />
<Column Name="CategoryName" Type="System.String" DbType="NVarChar(15) NOT NULL" CanBeNull="false" />
<Column Name="Description" Type="System.String" DbType="NText" CanBeNull="true" UpdateCheck="Never" />
<Column Name="Picture" Type="System.Data.Linq.Binary"
DbType="Image" CanBeNull="true" UpdateCheck="Never" />
<Association Name="Category_Product" Member="Products" ThisKey="CategoryID" OtherKey="CategoryID" Type="Product" />
</Type>
</Table>
Not support -à
Conceputal model
1.
One database—entity(customer)---tightly coupled
with –one particular schema.-->dbo
Not support-à
Mapping Schema
2.
Association-à
these mappings are 1 to 1 relationships.
Not supportà Storage Schema
3.
Every Field tightly coupled with -à particular Storage
model.
---Open the .dbml-àwith xml Editor(northwind.dbml)
and Design view
(northwinddesignder.cs)
All ther are included as a single
file--à
Northwind.dmlàopen with xml Editor
2.
Rapid application Development .
Application---Linq to sql—ADO.NET----
SQL SERVER.
Linq to SQL generate objects(in front end
application) which are directly map to database tables so here object are equal
to Relational table.
ORM-mapper maps a relavent designer code in northwind.designer.cs
surface.
As par Table Relationships and stored
procedures which generates apporiate code in LINQ-to-sql designer.
And
EntityRef---tells --à Reference tablesà FK
EntitySet---tells---à
[Table(Name="dbo.Products")]
public partial class Product : INotifyPropertyChanging,
{
private EntitySet<Order_Detail>
_Order_Details; this Attribute are
field--à shared by
Product and Order_Details-à So EntitySet.
which is shared by multiple entities which
share a single attribute.
Order_Details--à
private EntityRef<Category>
_Category;---à field
reference CategoryID.
private EntityRef<Supplier>
_Supplier;--à field reference SupplierID.
[Association(Name="Product_Order_Detail", Storage="_Order_Details",
ThisKey="ProductID", OtherKey="ProductID")]
public EntitySet<Order_Detail> Order_Details
{
get
{
return this._Order_Details;
}
set
{
this._Order_Details.Assign(value);
}
}
[Association(Name="Category_Product", Storage="_Category", ThisKey="CategoryID",
OtherKey="CategoryID", IsForeignKey=true)]
public Category Category
{
}
[Association(Name="Supplier_Product", Storage="_Supplier", ThisKey="SupplierID",
OtherKey="SupplierID", IsForeignKey=true)]
public Supplier Supplier
{
}
Entity Framework:
In case of Entity framework -----in single
.edml file 3 parts are sperated.
Supports à Conceptual model.
<edmx:ConceptualModels>------------only entities.
Supports -> Storage model
Supports-à Mapping model(conceptual and storage).
This specifies <edmx:Mappings>
Conceputal
type(EntityType) to Storage type.
<edmx:Mappings>
<EntitySetMapping Name="Employees">
<EntityTypeMapping TypeName="IsTypeOf(NORTHWNDModel.Employees)"><MappingFragment StoreEntitySet="Employees">
Entity
Framework
Works with
Conceptual model of database.----loosely coupled.
One
Conceptual model-à one conceptual layer and then multiple mapping layers that point to
mulitple database
Conceptual model
 |
 |
||||
Enterprise Development:
Yes, In linq to sql-à
DataContext--à
in Entity Framework---- ObjectContext.
In linq to sql-à The mapping of the logical
schema into the physical schema that defines how the data is structured and
stored on the disk is the job of the database system and client side data
access mechanisms are shielded from it as the database exposes the data in the way
specified by its logical schema(at client side).—tightly coupled.
Using LINQ to SQL,
developers can write code directly
against the storage schema using the same LINQ programming pattern as
previously described for in-memory collections, Entities. The Entity data model (EDM) specifies the conceptual model of the
data via the Entity-Relationship data model.
public System.Data.Linq.Table<Product>
Products
{
get
{
return this.GetTable<Product>();
}
}
[Table(Name="dbo.Products")]
public partial class Product {}
using (NorthwindDataContext context=new NorthwindDataContext())
{
IQueryable<Product> s = context.GetTable<Product>();
Console.WriteLine(s.Count<Product>());
}
--working with storage
schema(AGANIST DATABASE).in LINQ TO SQL.***************
Means data models(Product) are tightly map to Database tables.aganist
works with database(directly).
Ex:
using (NorthwindDataContext context=new NorthwindDataContext())
{
Customer
firstCustomer = context.Customers.First();
Console.WriteLine("Customer name : {0}",
firstCustomer.ContactName);
var
orders = firstCustomer.Orders;
foreach (var order in orders)
{
Console.WriteLine("Order ID : {0} dated : {1}",
order.OrderID, order.OrderDate.Value.ToLongDateString());
}
}
Output:
In Entity
framework ---developers work with Conceptual schema which maps the logical
schema and Physical schema.
Ex:
using (NorthwindDataContext context=new NorthwindDataContext())
{
Customer
firstCustomer = context.Customers.First();
Console.WriteLine("Customer name : {0}",
firstCustomer.ContactName);
var
orders = firstCustomer.Orders;
foreach
(var order in
orders)
{
Console.WriteLine("Order ID : {0} dated : {1}",
order.OrderID, order.OrderDate.Value.ToLongDateString());
}
}
Here firstCustomer object works with only the relavent --> EntitySet data only.
Working with CONCECPTUAL schema(NOT AGANIST DATABASE).in LINQ TOSQL.***************
Designer changes
linq to sql(direction Connection)
why because no conceptual model in linq to sql.
Entity Framework
linq to sql direct mapping
in entity framework is generated as unified model to work with any database.
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