Vishal wrote:
<<
...
Here, my doubt is Using Delphi 5 and Firebird database, is it
possible for all the instances of this application which are
installed at different cities could access one centralized database ?
If yes then HOW ?
...

>>

You need a fixed IP address for the machine which is hosting the
database (the db server). Your program - wherever it runs - just
need to use a connection string with <IP address or machine
name>:<database path and filename, or alias>, e.g.
123.234.123.234:D:\DB\ourdb.fdb (or possibly
VISHAL_SERVER:LIBRARY_DB, with necessary definitions in place).
You may have to persuade administrators to open port 3050 in
firewalls (in- and outbound).


--
Aage J.