It is unnecessary and inefficient for each store to have a copy of the entire consolidated database. The remote schema uses the same table names, but only contains information relevant to one particular store. To achieve this, the remote schema is designed as a subset of the consolidated database in the following way:

Each store needs to keep records of all titles and authors so customers can search their inventory. However, a bookstore does not need information about publishers or royalties, so this information is not synchronized to each store. Each store needs information about sales and discounts, but not about sales and discounts related to other stores. This is achieved by filtering rows based on a store identifier.

The next step is to choose the synchronization direction of each table. You should consider what information a remote database needs to read and what information a remote database needs to create, change, or remove. In this example, a bookstore needs access to the list of authors and titles, but never enters a new author into the system. This places a restriction that authors and titles must always enter the system from the consolidated database at headquarters. However, a bookstore needs to be able to record new sales on a regular basis. These factors lead to the following synchronization directions for the tables: