CODEWITHSUNDEEP
c#asp.netdatabasewebformsdataset
ezechiele2517
ezechiele2517

Reputation: 375

ASP.NET C# - using dataset to read one row?

I'm developing a classic WEBForms application in C# and when I have to authenticate the user, I read from SQL database the user data using a query like that: 

SELECT userid,username,email,city FROM USERS where username='blablabla' and password='blablabla'

I want to use this sql query in my method that returns a DTO Object that I defined in my UserValue class. I'm thinking to use a dataset to fill user data executing the query.
Is it the correct approach or is it too expensive and useless to use dataset to read one row from a query?

Can you advice me?

thanks

Upvotes: 3

Views: 7869

Answers (2)

Ajay
Ajay

Reputation: 2080

For getting only one record from database or one by one record from database,"Data Reader" is Good Approach.Check the sites below You can get clear Idea on Data Reader.

http://www.aspdotnet-suresh.com/2012/10/aspnet-difference-between-datareader.html http://msdn.microsoft.com/en-us/library/haa3afyz.aspx http://www.akadia.com/services/dotnet_data_reader.html

Upvotes: 4

Tim
Tim

Reputation: 28520

Here's a code snippet (this is for MS SQL, but other flavors of SQL should be similar) to illustrate what I'm talking about in my comment:

using (SqlConnection con = new SqlConnection(connectionString))
{

    con.Open();

    SqlCommand cmd = new SqlCommand("SELECT userid,username,email,city FROM USERS where username=@username and password=@password", con);
    cmd.Paramters.AddWithValue("@username", username);
    cmd.Parameters.AddWithValue("@password", password);
    cmd.CommandType = CommandType.Text;

    UserInfo info = new UserInfo();

    using (SqlDataReader rdr = cmd.ExecuteReader())
    {

        if (rdr.HasRows)
        {
            rdr.Read(); // get the first row

            info.UserID = rdr.GetInt32(0);
            info.UserName = rdr.GetString(1);
            info.Email = rdr.GetString(2);
            info.City = rdr.GetString(3);
        }
    }
}

This example also shows how to do parameterized queries, which are essential for preventing SQL Injection attacks.

Also, rather than looping through the reader, I check to see if it has rows and if it does I read the first row only (and since you're dealing with user information there should theoretically be only one row) and populate the DTO.

Hopefully this will illustrate my comment to your question.

Upvotes: 3

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