Letting user select Unique Identifier of dynamic data?

Question

I'm creating an app that lets companies view analytics about their employees. The manager of the company will upload all their employees' data and the app will run analytics on it.

The problem is that different companies use different ways to uniquely identify their employees. For example, one company can have an employeeId number, while another company might use the email to identify different employees.

Company 1:

[
  {
    "firstName": "John",
    "lastName": "Doe",
    "email": "johnDoe@company.com",
    "employeeId": "1234"
  },
  {
    "firstName": "Cat",
    "lastName": "Dog",
    "email": "catDog@company.com",
    "employeeId": "5678"
  }
]

Company 2:

[
  {
    "firstName": "John",
    "lastName": "Doe",
    "email": "johnDoe@company.com",
  },
  {
    "firstName": "Cat",
    "lastName": "Dog",
    "email": "catDog@company.com",
  }
]

My proposed solution is to make the managers select the field they use to uniquely identify their employees when they're uploading the data, then use that field as the unique ID in the database. However, I'm wondering if this is good practice. Should I also hash the value of the unique field they chose and use that instead of just the raw value?

Does anyone know if this is a common practice?

Answer 1

different companies use different ways to uniquely identify their employees.

Presumably, they would have to map their data fields to yours somewhere along the line. Given them the option to say which field is the unique identifier.
Job done.

... an app that lets companies view analytics about their employees ... upload all their employees' data and the app will run analytics on it.

We look forward to seeing your Privacy Notice and all the other legalese that you'll need to produce about how you intend to curate other peoples' Data.