How to connect with SQL database?

For connecting to SQL Database, you can directly write a connection string in the C# code like
SQLConnection sConn = new SQLConnection();
sConn="Data Source=xyz;Initial Catalog=myDtbase;User ID=sl;Password=sa"
But the proper way to do it is by adding the connection string in a web.config, for example in
<configuration>
<appSettings>
<add key="conn1String" value="Data Source=xyz;Initial Catalog=myDtbase;User ID=sl;Password=sa"/> </appSettings>
</configuration> <appsettings><appsettings>
<add key="conn1String" value="Data Source=xyz;Initial Catalog=myDtbase;User ID=sl;Password=sa">
</appsettings>
<add key="conn1String" value="Data Source=xyz;Initial Catalog=myDtbase;User ID=sl;Password=sa">
</configuration></appsettings></configuration>
In C# code , just define
string connString = ConfigurationSettings.AppSettings["conn1String"];
sConn =connString;
Data Source : has to be the complete machine name\SQLExpress
Initial Catalog : has to be the database name
User ID and Password : If you use other than windows authentication If it is windows authentication, just give Integrated Security=SSPI;