I have a client that have 100 sites that display information from a database currently they are running individual databases for each sites. I was wondering if it was possible for all these 100 sites to use one database as they are all exact same script. All they do is pulling information out of database and doesnot write anything. So it is possible to use one database for 100 sites. Each site recieves about 200 user per day.
If the appliction / site is written to support this then the answer would be yes, if no such support is given you are doing something the author did not anticipate so you would need to ask the author or test and validate for yourself if this site can run with a single database/table solution. The more important question to me is the motive for trying to merge multiple databases, what are the gains you receive when doing this. P.S. This is only interesting if you are trying to merge into a single table.
It is not possible to do so if the script does not supports multiple database. I think you should find an CMS that support multiple sites with just one database such as dotnetnuke