Today, I started to learn about connection objects in ADO. Net (I)-connection SQL Server with sqlconnection objects

The connection object is used to establish a connection channel with the data source.
First, let's look at an instance:

Using system;
Using system. Data;
Using system. Data. sqlclient;// SQL Server Data SourceProgram

Namespace consoleapplication1
{
Class Program
{
Static void main (string [] ARGs)
{
String connectionstring = getconnectionstring ();
String querystring = "select * From DBO. t_student ;";
// Create a connection object
Sqlconnection connection = new sqlconnection (connectionstring );
{
Try
{
Connection. open (); // Open the database connection
Console. writeline ("successfully connected to SQL Server 2005 Database ");
Console. Readline ();

Connection. Close (); // Close the database connection
Console. writeline ("successfully shut down the database to SQL Server 2005 ");
}
Catch (sqlexception ex)
{
// Tostring () is used to convert exception information to string display.
Console. writeline (ex. tostring ());
Console. Readline ();
}
}
}
Static private string getconnectionstring () // Return the function of the connection string
{
Return "Integrated Security = true; initial catalog = database name; server = server name ";
}
}
}

Complete ~~!

Attribute	Description
Connectionstring	String used to open or connect to the database
Connectiontimeout	All waiting time before the connection is terminated and an error is generated
Datebase	Name of the database to be used after the left connection of the front database is opened
Stat	Current connection status

Method	Description
Open	Open a connection to the database
Close	Close the current connection to the database
Createcommand	Create and return a command object related to the connection
Begintransaction	Start database transactions
Changedatabase	Change the database of the currently opened connection object