Extracting selected records from Dataset

In Visual Studio select "Data | View Data Sources". In the Data Sources window click on "Add New Data Source". In the "Choose a Data Source Type" window choose "Database". In the "Choose a Data Model" select "Entity Data Model". In the "Choose Model Contents" window choose "Generate from database". In the "Choose Your Data Connection" window select your database; you might need to click on the "New Connection" button. Be sure to leave the chckbox checked for saving the connection string. In the "Choose Your Database Objects" window choose the table. When you click finish a "model" (such as Model1.edmx) is created. The articleCreating an Entity Data Model (Entity Framework 4 shows how to do all that. Once you do all that, most of the programming is done.

Then go back to the Data Sources window. It will show you the "Entities" (such as WhateverEntities) for your database and under that the table(s). If you look in the designer (Model1.edmx) window the top of each table will have the name of a class for each record in the table. So for example the table name in the Data Sources window might be Articles (with the "s") and the designer window will show "Article" without the "s".

You can connect to the dataase with a simple "using" as in "using (WhateverEntities we = new WhateverEntities())". Then you can use LINQ to query the table, as in:

using (WhateverEntities we = new WhateverEntities())
{
String s;
IEnumerable

Results =
from Result in we.Articles
where Result.Edited == false
select Result;
foreach (Article a in Results)
Console.WriteLine(String.Format("{0}|{1}|{2}", a.Article, a.Author, a.Title));
}

Or you can enumerate the records as in:

using (WhateverEntities we = new WhateverEntities())
{
foreach (Article a in we.Articles)
if (a.Edited == false)
ShowArticle(a);
}

4 Replies

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Sam Hobbs15y ago
In Visual Studio select "Data | View Data Sources". In the Data Sources window click on "Add New Data Source". In the "Choose a Data Source Type" window choose "Database". In the "Choose a Data Model" select "Entity Data Model". In the "Choose Model Contents" window choose "Generate from database". In the "Choose Your Data Connection" window select your database; you might need to click on the "New Connection" button. Be sure to leave the chckbox checked for saving the connection string. In the "Choose Your Database Objects" window choose the table. When you click finish a "model" (such as Model1.edmx) is created. The articleCreating an Entity Data Model (Entity Framework 4 shows how to do all that. Once you do all that, most of the programming is done.

Then go back to the Data Sources window. It will show you the "Entities" (such as WhateverEntities) for your database and under that the table(s). If you look in the designer (Model1.edmx) window the top of each table will have the name of a class for each record in the table. So for example the table name in the Data Sources window might be Articles (with the "s") and the designer window will show "Article" without the "s".

You can connect to the dataase with a simple "using" as in "using (WhateverEntities we = new WhateverEntities())". Then you can use LINQ to query the table, as in:

using (WhateverEntities we = new WhateverEntities())
{
String s;
IEnumerable
Results =
from Result in we.Articles
where Result.Edited == false
select Result;
foreach (Article a in Results)
Console.WriteLine(String.Format("{0}|{1}|{2}", a.Article, a.Author, a.Title));
}

Or you can enumerate the records as in:

using (WhateverEntities we = new WhateverEntities())
{
foreach (Article a in we.Articles)
if (a.Edited == false)
ShowArticle(a);
}
0
Datta Kharad15y ago
Hi
You can extract 30 records from dataset using select method of dataset.

DataSet ds;
DataRow[] dr;
dr=ds.Tables["Tablename or index"].Select("Here you where condition for 30 records");
0
Satyapriya Nayak15y ago
Hi Stephen,

Use query like,

select top 30(name) from employee

select top 40(name) from employee

SqlConnection con = new SqlConnection(connStr);
        con.Open();
        str = "select top 40(name) from employee";
        com = new SqlCommand(str, con);
        sqlda = new SqlDataAdapter(com);
        ds = new DataSet();
        sqlda.Fill(ds, "employee");
        GridView1.DataSource = ds;
        GridView1.DataMember = "employee";
        GridView1.DataBind();
        con.Close();

Thanks
0
Mamta M15y ago
What's your criteria?
0