October 14, 2002 - The SqlConnection Class | WebReference

October 14, 2002 - The SqlConnection Class

Yehuda Shiran October 14, 2002
The SqlConnection Class
Tips: October 2002

Yehuda Shiran, Ph.D.
Doc JavaScript

Every time you want to retrieve records from an SQL database, you need to open a connection to it, read the records, and then close the connection. You accomplish this sequence with the SqlConnection object. You need to create an instance of SqlConnection, call its Open() method, read the records with an SqlCommand instance object, and then close the connection by either passing the constant CommandBehavior.CloseConnection to the SqlCommand instance object, or by calling the SqlConnection's Close() method.

The constructor of the SqlConnection object expects one parameter: the connection string. The connection string identifies the SQL server name, the SQL database name, and satisfies the authorization requirement by providing a user name and a password, or by specifying Trusted_Connection=true. You can specify the connection string in line within the constructor line, or you can specify it in Web.config. In IBuySpy, it is defined in Web.config as follows:

  <add key="ConnectionString"
    value="server=HAW2L1800\NetSDK;Trusted_Connection=true;database=StoreDOCJS" />
Here is the constructor line repeated by each and every method of the five JScript .NET modules:

  var myConnection : SqlConnection  = 
    new SqlConnection(ConfigurationSettings.AppSettings["ConnectionString"]);
Here is how we open the connection, retrieve records from the database, and close the connection:

  myConnection.Open();
  var result : SqlDataReader  = 
    myCommand.ExecuteReader(CommandBehavior.CloseConnection);
And here is how we open the connection, retrieve some parameters (as opposed to records), and close the connection:

  myConnection.Open();
  myCommand.ExecuteNonQuery();
  myConnection.Close();