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Using Attribute Mapped Entities is normal.

it seems that the content of this aspect has not been found.

My problem has been solved

var
Icon:TIcon;
Query: ILinqQueryable;
begin
Icon := DataModule2.EntityContext1.CreateAttachedEntity<TIcon>;
Icon.Id :=1111;
Icon.Filename:='asdaaaaa';
Icon.Upname :='dddfd';
Icon.Upda :=VarToDateTime('05-10-14 04:35PM');
Icon.Save;

I am studying EntityDAC,execute the above code prompt "parameter 'returnId' not found", can not be saved, what is the reason?

https://www.devart.com/entitydac/docs/r ... ctions.htm


Declaration and initialization of a range variable that defines an initial sequence for a LINQ query
Declaration:

var
range-variable: IMetaDataExpression;
Initialization:

meta-type-name = string value

range-variable := data-context.Types[meta-type-name]
| range-variable := data-context[meta-type-name]
Sample:

var
Emp,
Dept: IMetaDataExpression;
begin
Emp := DataContext.Types['Emp'];
Dept := DataContext['Dept'];
end;

IMetaDataExpression In which unit?

var
Emp,
Dept: IMetaDataExpression;
begin
Emp := DataContext.Types['Emp'];
Dept := DataContext['Dept'];
end;

"IMetaDataExpression" can't find it in that unit.

I mean, can I query multiple tables in a single query.

EntityDAC can support multiple tables, how is it supported? I don't see how the multi-table works in the help documentation.