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Tuesday, April 30, 2019

Difference Between DataReader and DataAdapter in C#



DataReader

 
DataReader is used to read the data from database and it is a read and forward only connection oriented architecture during fetch the data from database. DataReader will fetch the data very fast when compared with dataset. Generally we will use ExecuteReader object to bind data to datareader.
 
To bind DataReader data to GridView we need to write the code like as shown below: 

  1. Protected void BindGridview() {  
  2.     using(SqlConnection conn = new SqlConnection("Data Source=abc;Integrated Security=true;Initial Catalog=Test")) {  
  3.         con.Open();  
  4.         SqlCommand cmd = new SqlCommand("Select UserName, First Name,LastName,Location FROM Users", conn);  
  5.         SqlDataReader sdr = cmd.ExecuteReader();  
  6.         gvUserInfo.DataSource = sdr;  
  7.         gvUserInfo.DataBind();  
  8.         conn.Close();  
  9.     }  
  10. }   

  • Holds the connection open until you are finished (don't forget to close it!).
  • Can typically only be iterated over once
  • Is not as useful for updating back to the database

DataAdapter

 
DataAdapter will acts as a Bridge between DataSet and database. This dataadapter object is used to read the data from database and bind that data to dataset. Dataadapter is a disconnected oriented architecture. Check below sample code to see how to use DataAdapter in code: 

  1. protected void BindGridview() {  
  2.     SqlConnection con = new SqlConnection("Data Source=abc;Integrated Security=true;Initial Catalog=Test");  
  3.     conn.Open();  
  4.     SqlCommand cmd = new SqlCommand("Select UserName, First Name,LastName,Location FROM Users", conn);  
  5.     SqlDataAdapter sda = new SqlDataAdapter(cmd);  
  6.     DataSet ds = new DataSet();  
  7.     da.Fill(ds);  
  8.     gvUserInfo.DataSource = ds;  
  9.     gvUserInfo.DataBind();  
  10. }   

  • Lets you close the connection as soon it's done loading data, and may even close it for you automatically
  • All of the results are available in memory
  • You can iterate over it as many times as you need, or even look up a specific record by index
  • Has some built-in faculties for updating back to the database.

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