5. Simple Relationship Expression for TADB Normal Group Attributes
Procedure
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There are two Item types (in the expression), defined as follows.
Order Invoice information includes what the customer wants. Customer Information includes address and billing. -
There is one Attribute group (in the expression), defined as follows.
Address Attributes include State
. -
When an Order item is created, it is associated with the Customer item that should receive the finished product.
Query Expression
TestItem(“Order1”,”Customer{Address.State=’NY’}”)
Where
Criteria Is/are the: TestItem Sub-expression test. Order1 Order item State Address group attribute 'NY' State attribute value. Expression says:
Find
Customer
items that have a relationship with the item Order1Where the
Customer item’s Address (group) contains NY as the value for its State (attribute).
Note: The relationships are looked for in the TADB’s RelatedItems table.
.bnf syntax Expression
ItemType{Expression}
This syntax means that:
- Relationships can be combined and nested to near limitless complexity
- Parentheses can be combined and nested to near limitless complexity.