In this tutorial we will learn table splitting in
entity Framework. Table Splitting is just opposite of Entity Splitting.
In entity Splitting Means Split this entity into multiple database table but in Table splitting we split one table into two tables.
Entity Splitting refers
to mapping an entity in to two or more tables when the tables have a common key
(common column).
Why we Use Table Splitting in EF :
One reason of this question is that when we want to delay of some property
means Lazy loading of to load your objects.
How we use Table splitting in EF, we will understand
with an example.
Step(1) : First of all create a table with name
Student.
For this execute below script in SQL server.
Create table Students
(
StudentID int primary key identity,
FirstName nvarchar(50),
LastName nvarchar(50),
Gender nvarchar(50),
Email nvarchar(50),
Mobile nvarchar(50)
)
Insert into Students values ('Munesh', 'Sharma', 'Male','m@g.com','5555555555')
Insert into Students values ('Rahul', 'Sharma', 'Male','R@g.com','333333333') Insert into Students values ('Sara', 'vilium', 'Female','S@g.com','111111111') Insert into Students values ('Mark', 'hash', 'Female','M1@g.com','2222222222') Insert into Students values ('ABC', 'EFG', 'Male','A@g.com','6666666666') |
After execute this script you will see a table in your
database With the name Student.
Now go to your application and Right click on solution
explorer and add a “ADO.Net Entity Data Modal” and select database first
approach.
After that click on next and select database connection
and select database name and then click on next and select your tables which
is created now, And click FINISH
When you click on FINISH you will see one “Student”
Entities
Now in this entity we have Mobile
and email properties, these properties we are
not using everywhere like Firstname , Lastname, Gender properties. If we will
load Student entity these all entity will load automatically, So now we will create 2 entities (Student ) &
(StudentContactDetails).
For Getting this there are some steps
(1)
:Right click on the Entity designer and
click on “Add entity” .And Set some values here
(a)
: Entity Name = StudentContactDetail
(b)
: Base type = None
(c)
: Entity Set = StudentContactDetail
(d)
: Key Property check Box = checked
(e)
: Property name : StudentId
(f)
: Property type : Int32
(2)
: Now Cut Mobile And Email From Student
entity and pest it into StudentContactDetail.
Then
entity will look like that
(3)
Again Right click on entity designer and
Add a “Association” And fill the Some details
(4)
Now Right click on Association And click on
properties , when you will click on property a window will open from there
select “ Referential Constraint” and fill Details
(5)
Now right click on StudentContactsDetails
entity and click on mapping.
(6)
Right click on solution explorer and add a
Webform and Dragdown a gridview and 2 buttons.
<div style="font-family:Arial">
<asp:Button ID="FullDataWithContactDetail" runat="server" Text="GetStudent
Data with contact detail"
onclick="Button1_Click" />
<br />
<asp:Button ID="Button2" runat="server" Text="Get Student
Data"
onclick="Button2_Click" />
<asp:GridView ID="GridView1" runat="server">
</asp:GridView>
</div>
|
(7)
Write below code on this Webform(In code
Behind file)
public partial class WebForm1 : System.Web.UI.Page
{
private DataTable GetStudentData()
{
StudentDBContext _studentDBContext
= new StudentDBContext();
List<Student> _students = studentDBContext.Student.ToList();
DataTable dt = new DataTable();
DataColumn[] columns =
{ new DataColumn("StudentID"),
new DataColumn("FirstName"),
new DataColumn("LastName"),
new DataColumn("Gender")};
dt.Columns.AddRange(columns);
foreach (Student students in _students)
{
DataRow dr = dt.NewRow();
dr["StudentsID"] = students.StudentsID;
dr["FirstName"] = students.FirstName;
dr["LastName"] = students.LastName;
dr["Gender"] = students.Gender;
dt.Rows.Add(dr);
}
return dt;
}
|
private DataTable GetStudentDatawithContactDetails()
{
StudentDBContext
_studentDBContext = new StudentDBContext();
List<Student>
_student = _ studentDBContext.Student
.Include("StudentContactDetail").ToList();
DataTable dt
= new DataTable();
DataColumn[]
columns = { new DataColumn("StudentID"),
new DataColumn("FirstName"),
new DataColumn("LastName"),
new DataColumn("Gender"),
new DataColumn("Email"),
new DataColumn("Mobile")
dt.Columns.AddRange(columns);
foreach (Student
student in _student)
{
DataRow dr
= dt.NewRow();
dr["StudentID"] = student.StudentID;
dr["FirstName"] = student.FirstName;
dr["LastName"] = student.LastName;
dr["Gender"] = student.Gender;
dr["Email"] = student.StudentContactDetail.Email;
dr["Mobile"] = student.StudentContactDetail.Mobile;
dataTable.Rows.Add(dr);
}
return dt;
}
protected void Button1_Click(object sender, EventArgs e)
{
GridView1.DataSource = GetStudentDatawithContactDetails ();
GridView1.DataBind();
}
|
protected void Button2_Click(object sender, EventArgs e)
{
GetStudentData();
}
|
(8)
Now Run your application and check your
data with contact detail and without contact detail.
