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As a consequence of the transient nature of generated local keys, it is not possible to define navigation properties
on these entities or use them in filter or order by conditions.
OData Associations
You can define associations between entities to express relationships between entities. With associations it is
possible to reflect foreign key constraints on database tables, hierarchies and other relations between database
objects. OSDL supports simple associations, where the information about the relationship is stored in one of the
participating entities, and complex associations, where the relationship information is stored in a separate
association table.
Associations themselves are freestanding. On top of them you can specify which of the entities participating in the
relationship can navigate over the association to the other entity by creating NavigationPropertys.
For the examples used to illustrate OData associations, we use the tables customer and order:
Table definition: sample.odata:customer.hdbtable
table.schemaName = "ODATASAMPLES";
table.tableType = COLUMNSTORE;
table.columns = [
{name = "ID"; sqlType = INTEGER; nullable = false;},
{name = "RecruitID"; sqlType = VARCHAR; nullable = true;}
];
table.primaryKey.pkcolumns = ["ID"];
Table definition: sample.odata:order.hdbtable
table.schemaName = "ODATASAMPLES";
table.tableType = COLUMNSTORE;
table.columns = [
{name = "ID"; sqlType = INTEGER; nullable = false;},
{name = "CustomerID"; sqlType = INTEGER; nullable = false;}
];
table.primaryKey.pkcolumns = ["ID"];
There is one relationship order.CustomerID to customer.ID and one relationship
customer.RecruitID to customer.ID.
SAP HANA Developer Guide
Defining Web-based Data Access
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