DObject O/R Mapping suite provides expert OQL.Delphi object query language to assist querying data-object and data object-set from database or object-set, a sample is as follows:
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var orders : IObjectSet; orders2 : IObjectSet; order : IOrder; begin // from database orders := ObjectManager.GetObjectSet( NW.Order, OQL.Criteria(NW.Order.EmployeeID).EQ(4) ); // get sub set orders2 := orders.GetSubSet( OQL.Criteria(NW.Order.ShipVia).EQ(1) ); // find first order := orders.Find( OQL.Criteria(NW.Order.ShipVia).EQ(3) ) as TOrder; end; |
When OQL is used to query data-object in memory, it doesn't support multi-table's Join, Sub- query as well as Case, Like and Function.
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