Scenario 5: Modelling the Buyer to Sales transaction relationship

[Linda_Stinson]

Using what you have learned, how would you model the relationship between a buyer and their sales transactions? What would you add and to what schema? What would be the impact on the underlying tables?

[ruby_comp]

1) M:M

2) Add a database index to the srcSchema

3) Impact would be improved speed

[Linda_Stinson · Accepted solution]

Keeping in mind that every order has a single buyer, but every buyer (Recipient) can have multiple orders, you would define the link in the order schema.  Most relationships are 1:1 in one direction and 1:M in the reverse direction.  You define the link in the 1:1 "direction". This has been done with neo:order.

    <element label="buyer" name="buyer" target="nms:recipient" type="link"/>

The reverse link (revlink) is generated (and can be viewed in the Preview) but not stored in the database as shown in the nms:recipient schema Preview:

<element label="order" name="order-buyer" revLink="buyer" target="neo:order" type="link" unbound="true">

      <join xpath-dst="@buyer-id" xpath-src="@id"/>

    </element>

To define a true M:M relationship you have to define a table to hold each relationship. This has been done with the xtk:rights schema that is used to configure the Operator rights on folders. Each entry in this table has a link to an Operator or Operator Group and a link to a Folder:

   <element desc="Right associated to folder" label="Folder" name="folder" revIntegrity="own"

             revLabel="Rights" revLink="rights" target="xtk:folder" type="link"/>

    <element label="Operators or groups" name="operator" revIntegrity="own" revLabel="Rights"

             revLink="rights" target="xtk:opsecurity, xtk:operator" type="link"/>

Hope this helps!