Web app security with ldap and unique identifier for user

If I use LDAP to store users and for authentication for my web application, but I have already created profiles in the system for the users before they have registered themselves, should I have two separate identifiers?

For example, I have a hair salon with Employees and Clients. The Employees are all users of the system, with their own permissions. Clients may create accounts, or may not, to see their scheduled appointments and other information. As the Clients are created in the system by the business and may, or may not, register, do I create a class with a Client_ID that I then associate with a User? So, do I need two different identifiers?

In my LDAP directory, do I have an attribute called client_ID that I use after authentication to associate all of the Client's data with the User account?

*Note: I am new to using LDAP, and the application, which has nothing to do with a hair salon, stores all of the information in an SQL database. I just want to use LDAP to maintain separation of data and to authenticate users.