DSN stands for 'Data Source Name'. It is an easy way to assign useful and easily rememberable names to data sources which may not be limited to databases alone. If you do not know how to set up a system DSN read our tutorial How to set up a system DSN.
For our example below lets assume that our DSN points to an Access database called 'examples.mdb' and that we will be selecting records from the table 'cars'.
Remember that 'myDSN' above is name of the DSN. Also note that you can change the table name from 'cars' to the name of your table and point the DSN to whatever database you like. One other thing to remember is that you can set up a DSN on your own machine though if you are using a hosting company you may have to ask the webmaster.
DSN-less connections don't require creation of system level DSNs for connecting to databases and provide an alternative to DSNs. We will now see how to connect to a database via PHP using Connection String in place of DSN name.