buyer & seller table structure

[mangel.murti]

For one order XYZ can be a buyer and for different order XYZ will be a seller.
how to assign buyer and seller responsibilities to users per order basis. give me some example of table structure.

thanks in advance

[pritaeas]

What do you have so far?

[mangel.murti]

Thanks for your reply.

In general i have setup user_table

1. user_id
2. name
3. user_type_id
   ......etc..

user_type

1. user_type_id
2. type (like.... admin, seller , buyer...etc)
   ....etc...

order_table

order_id,
user_id,
trasaction_id
amount
..etc....

every user can be buyer or seller. need to clear concept with database..
1. how to assign buyer and seller responsibilities to users per order basis.
if lets say i removed user_type_id form user_table. so how can i recognize a user if he is buyer or seller? is it possible without maintaning a user_type in your application you can recognize what is user buyer or seller?
2. let say some how i maintain database structure and later on i have to show hide some infomation from either buyer or seller. i mean buyer will not able to see XYZ infomation but seller can see. seller can see buyer can not see etc....