How can I store data against specific contact ID?

Question

I want to store some additional data for each contact on Android.
I would have in mind creating my own database table for it, and then bind them to the real contact via a unique id.

I am wondering if Android has built in functionality to store additional data against contacts?

EDIT 2
Is there a defined field for birthday of the contact? How do I store a date field?

Answer 1

Where is ContactsContract.Data class declares Content URI to store additional contact information ( phones, emails and IM statuses for example are all implemented in similar ways) Take a look at ContactsContract.CommonDataKinds for an example of implementation.
Basically you've got CONTACT_ID,MIME_TYPE and data columns to store data you want