>1. What is the limitation of a table? It will have a max. file size or a max. no. of record? (VFP 5.0)

The Maximum # of records per table file is 1 billion.
The Maximum size of a table file is 2 gigabytes .

>2. If I want to use VFP to build a server/client application (I want 10 or 20 clients to share, read//write the same VFP database), is it a must to use other database like MS SQL server or Oracle? I read from a QUE book that the software requirement of a "Server Application" is another database like SQL server or Oracle?

You don't have to use MS SQL Server or Oracle to build multi-user application. VFP can handle 10-20 users and more.

Take a look at Thread Thread #530039 and Thread #504606 for same discussion on that matter.