>does useing backend like sqlserver or oracle slow vfp
>than using dbfs.

Rajesh,

performance related questions can be seldom answered with a yes or no, there are to many "parameters" involved.

In a network configuration oracle and ms server will return over the network only the result of your select, but vfp will load all the dbfs and cdx files over the network in the memory of the client computer and only there do the select (i think one of the recent issus of fox advisor featured an article about the behavior of vfp in such a situation).