sql server 2012 - New database or index key for each client? -

we building web application using asp.net , microsoft sql server 2012. each of our customer have ability add other customers below them.

our company --> our customers ---> customer's customers

is preferable create new database each of our customer or use seperate table , automatically apply key filter in gui?

from have described (briefly) not suggest having separate db each client. if each client getting own application/website, yes, may want have each client have own instance of db (as application, server, etc). in case, seems each client need interact 1 another. difficult if located in various databases. instead, creating normalized database schema uses recursive table customers. can create schema similar this:

tblourcompany

companyid(pk int)

companyname(varchar) ....

tblourcustomers

custid(pk int)

custname(varchar)

custparent(int)

tblcompany_customer

companyid(pk)

customerid(pk)

this quick mock table has company table (assuming have multiple companies or maybe might business units) , customers table. because may have multiple companies multiple customers, need have table unifies them both, company_customers table. crux of design, though, recursive design of customers table. each table have customerid, primary key, , parent id. parent id pk of customer found in customer table ( root parent have value of 0). example:

companyid | companyname  | parentid ----------------------------------- 1             companya     0 2             companyb     0 3             companyc     1 4             companyd     1 5             companye     4 

this example has 5 companies. 2 root companies (companya/b). companya has 2 children (c , d). companye has 1 child, companyd.

it important understand database normalization. if follow first inclination use different db each customer, spending great deal more money (db licenses cost money + server costs + space, etc) , causing unnecessary difficulty when comes getting data , working using sql , whatever applications may using it. heres quick intro normalization: http://databases.about.com/od/specificproducts/a/normalization.htm

if have other questions, let me know.