Reducing duplicates.

 We have a lot of duplicate accounts in our database due to the way people enter account name when they create one. For E.G. ABC Ltd. can be written as Abc Ltd. or abc, Ltd. etc.

we follow the logic that a company will have one main phone line so that should act as a unique identity of the company, however due to primary key in Siebel being the company name and the company location (phone number) this seems to be a challenge.

 

So my question is, without using web services is there a way of looking up the phone number in the existing database and give users an error if they are creating a company with the same number?