It’s a bit hard developing in different languages using different databases. And most of the times, I forget the connection string that I should use.

The following three connection strings would probably be the strings that I’d use often:

Oracle
Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=MyHost)(PORT=MyPort))(CONNECT_DATA=(SERVICE_NAME=MyOracleSID)));User Id=myUsername;Password=myPassword;

SQL Server 2005 (Standard Security for .NET)
Data Source=myServerAddress;Initial Catalog=myDataBase;User Id=myUsername;Password=myPassword;

SQL Server 2000 (Standard Security for .NET)
Server=myServerAddress;Database=myDataBase;User ID=myUsername;Password=myPassword;

Another syntax is this:
Data Source=myServerAddress;Initial Catalog=myDataBase;User Id=myUsername;Password=myPassword;

If you’re looking for other connection strings, visit ConnectionStrings.com. They have connection strings not only for databases but also for other files such as Excel and Active Directory.