Multiple databases or tables with prefix? I was creating an Accounting ERP for a multibrach company.Normally i would keep different databases for different branches, Can anyone tell me which is the standard way?
1) create databases respective to branches
2) keep single database and arrange tables with branch prefix
It's not simply a question of plugging values into an equation and, hey presto, you have an answer (as @dbdemon also points out - no standard solution).  

You need to put considerable thought into this - it could be a choice which affects you for a considerable time.

A few things you should do before you start coding:


Gather detailled requirements (as kindly suggested by @Peter) 
Check out the threads and a few of my answers on multi-tenancy here. Also, as suggested by @Colin'tHart, do a search on this site for other posts related to multi-tenancy.
You could also download a few Open Source apps - use your search engine of choice - duckduckgo got me a few links.
Take a look at databaseanswers and their schemas - something there might be of interest/help.
Do a bit of prototyping - see what "fits" with your company/clients/stakeholders requirements and/or your company's skillset in the coding/database areas.