Mark
There is really no need to use TInterfacedObject (which makes your choice of
bases class more flexible)
I'm future profing my TDataSet code with an interface
TADOEntity = class(TADOQuery, ImwkEntity)
end
where
ImwkEntity = interface(IUnknown)
['{181305E0-4E7F-11D4-A02F-00E018A81F7C}']
function ApplyUpdates: boolean;
function CancelUpdates: boolean;
function UpdatesPending: boolean;
function Mode: TEntityMode;
function GetMetaName: string;
function GetMetaServer: TmwkMetaServer;
procedure SetMetaName(Value: string);
procedure SetMetaServer(Value: TmwkMetaServer);
function GetMetaEntity: TmwkMetaEntity;
function KeyedFieldName: string; // Returns either the PrimaryKey or
KeyField with a matching Param
function SetEmpty: boolean; // Trys to set a open dataset to
IsEmpty = true
function NewEntity(AOwner: TComponent): ImwkEntity;
function SetSQL(SQL: string): boolean;
function SetEntitySize(Size: TEntitySize): boolean;
function DataSet: TDataSet;
function FieldDataType(index: integer) : TEntityDataType;
procedure SetMaxRows(Count: integer);
property MetaServer: TmwkMetaServer read GetMetaServer write
SetMetaServer;
function KeyLocate(const FieldName: string; Value: Variant): boolean;
procedure Free;
end;
2 things of note about this interface
1/ function DataSet: TDataSet; exposes the TDataSet parent (prob 90% of
what you do with a TDataset descendant
is in the base class
2/ function NewEntity(AOwner: TComponent): ImwkEntity; creates another
dataset of the same class (used for runtime lookup creation)
and in your code you then always make reference to your compnoent via the
Interface ie
var
EntInt: ImwkEntity;
Lookup: ImwkEntity;
begin
if Query.GetInterface(ImwkEntity, EntInt) then
with EntInt do
try
DataSet.FieldByName('Test') := 0 ; // example of using the TDataset
exposed
...
If you use dynamically created components and a compile time switch then
support for multiple TDataSet descendants is a breeze
HTH
Neven
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