> # Connecting Using a Connection String

> If you want to use a connection string for connecting to a database, or if your application requires it, you must specify either a DSN (data source name) or a DSN-less connection in the string. The difference is whether you use the DSN= or the DRIVER= keyword in the connection string, as described in the ODBC specification. A DSN connection string tells the driver where to find the default connection information. Optionally, you may specify attribute=value pairs in the connection string to override the default values stored in the data source.

> If your application requires a connection string to connect to a data source, you must specify the data source name that tells the driver which data source to use for the default connection information. Optionally, you may specify attribute=value pairs in the connection string to override the default values stored in the data source.

> The DSN connection string has the form::

>     DSN=data_source_name[;attribute=value[;attribute=value]...]

> For example, a connection string for SequeLink may look like this:

>     DSN=Accounting;DB=EMP;UID=JOHN;PWD=XYZZY

> or

>     DSN=Accounting;DB="X:IV;EMP";UID=JOHN;PWD=XYZZY

> NOTE: If the database name (DB) contains a semicolon (;), you must place the name in quotes, as shown in the preceding example.

> The DSN-less connection string specifies a driver instead of a data source. All connection information must be entered in the connection string because there is no data source storing the information.

> The DSN-less connection string has the form:

>     DRIVER=[{]driver_name[}][;attribute=value[;attribute=value]
>     ...]

> NOTE: Empty string is the default value for attributes that use a string value unless otherwise noted.

> A DSN-less connection string must provide all necessary connection information:

>     DRIVER=DataDirect SequeLink 6.0;DB=Emp;UID=JOHN;PWD=XYZZY

> See "ODBC Connection Attributes" for a list of ODBC connection attributes and their valid values.

> See "DSN-less Connections in Linux and UNIX" for more information about using DSN-less connections.