Multi Tenancy and User Definable Forms -

we designing our new product, include multi-tenancy. written in asp.net , c#, , may hosted on windows azure or other cloud hosting solution.

we’ve been looking @ mvc , other technologies and, honest, we’re getting bogged down in various acronyms (mvc, ef, wcf etc. etc.).

a particular requirement of our application causing headache – users able add fields database, or create whole new module.

as result, each tenant have database different structure every other tenant using system. envisage every tenant have own database, rather sharing database.

(adding fields etc. system accomplished using web interface).

all , good, problem comes when creating data model mvc. modifying data model programmatically add field table seems impossible, according link:

create edm during runtime?

this major headache us. if don’t use mvc, think we’d still want create data model (perhaps used linq sql).

we’re considering having table loads of fields in it, , instead of adding fields database allocate existing field in table when user wants add field form. not sure idea, though.

of course, don’t have use mvc or entity framework, appears me these kind of technologies microsoft steer towards future development.

any thoughts? i’m assuming we’re not first people in world consider idea of user-customisable application.

i'd make sure have explored option of creating 'name-value pair' type tables described here http://msdn.microsoft.com/en-us/library/aa479086.aspx#mlttntda_nvp before start looking @ customizable schema. don't forget going have grant higher permissions sql accounts in order them create tables on fly. customizable schema means sql accounts need higher permissions. wouldnt advisable assign these higher permissions tenants account, separate provisioning account can perform these tasks.

also before investing effort ef - try googling 'ef vote of no confidence'. raised (i believe) in reaction earlier versions definately worth reading on. nhibernate alternative worth investigating.