When creating a connection, you can use one of three sources: a Connection String, an OLE DB file (.UDL), or an ODBC Data Source Name (DSN). When using a DSN, it's likely you will not have to alter any of the other properties of the control. If you have created a Microsoft Data Link file (.UDL), select Use OLE DB File and click Browse to find the file on the computer. If you use a DSN, click Use ODBC Data Source Name and select a DSN from the box, or click New to create one. If you wish to use create a connection string, select Use
Standard Security is the default security Mode for SQL Server. When this mode is in use, the user must enter a login ID and password that have been established for the database. Integrated security allows SQL Server to use Windows authentication. With integrated security, users maintain a single login and password for both
ODBC is the native Interface to SQL Server. It allows you to connect to relational databases only. There are many ODBC driver available for the different relational databases on the market. OLE DB is a COM based low-level interface that will be abstracted for the programmer. It is the preferred database interface and is not limited to connecting to only relational data.
DSN-less Connections You can open a connection to a database without creating or specifying a named data source. Connections made in this way are called DSN-less, because they don’t require the system administrator to create an ODBC DSN. Rather than relying on information stored in a file or in the system registry, DSN-less connections specify the driver name, and all driver-specific information in the connection string. Whether or not to use a DSN depends on how much flexibility you want. Connection parameters are readily visible to system administrators. As a result, no matter which connection style you use, there are no extra security benefits. Probably the most common reason for using a DSN-less connection is to connect to a database on a system that is not under your direct control. This makes DSN-less connections good for testing and for applications under development. The following DSN-less connection strings contain the minimum parameters required by the ODBC drivers of Access and SQL 6.5: