I am using RemObjects DataAbstract along with Spring4d. RemObjects generates a SchemaServer_Intf.pas
file that contains interfaces for every kind of table that exists in it's schema. It allows for "Strongly typed" datasets, allowing one to access a field using
(aDataSet as IMyDataSet).MyField := aValue
Here is a snapshot of one of the interfaces generated by DataAbstract
IEntiteType = interface(IDAStronglyTypedDataTable)
['{96B82FF7-D087-403C-821A-0323034B4B99}']
{ Property getters and setters }
function GetEntiteIdValue: String;
procedure SetEntiteIdValue(const aValue: String);
function GetEntiteIdIsNull: Boolean;
procedure SetEntiteIdIsNull(const aValue: Boolean);
function GetNameValue: WideString;
procedure SetNameValue(const aValue: WideString);
function GetNameIsNull: Boolean;
procedure SetNameIsNull(const aValue: Boolean);
function GetIsSystemValue: SmallInt;
procedure SetIsSystemValue(const aValue: SmallInt);
function GetIsSystemIsNull: Boolean;
procedure SetIsSystemIsNull(const aValue: Boolean);
{ Properties }
property EntiteId: String read GetEntiteIdValue write SetEntiteIdValue;
property EntiteIdIsNull: Boolean read GetEntiteIdIsNull write SetEntiteIdIsNull;
property Name: WideString read GetNameValue write SetNameValue;
property NameIsNull: Boolean read GetNameIsNull write SetNameIsNull;
property IsSystem: SmallInt read GetIsSystemValue write SetIsSystemValue;
property IsSystemIsNull: Boolean read GetIsSystemIsNull write SetIsSystemIsNull;
end;
Though, there is one problem. If you cast a dataTable like so:
aDataTable := IEntiteType(TDAMemDataTable.Create(nil));
You'll have an "Interface not supported error"
But, as soon as you do:
aDataTable.LogicalName := 'EntiteType';
aDataTable.BusinessRulesId := MyBusinessRuleID;
You can safely write
aDataTable := IEntiteType(TDAMemDataTable.Create(nil));
And you don't get any error.
So, with Spring4d, I thought of writing this in my registration unit:
aContainer.RegisterType<TDAMemDataTable>.Implements<IEntiteType>.DelegateTo(
function : TDAMemDataTable
var aDataTable : TDAMemDataTable;
begin
Result:= TDAMemDataTable.Create(nil);
Result.LogicalName := 'EntiteType';
Result.BusinessRulesId := MyBusinessRuleId;
end
)
But then, Spring4d throws (with reason) error :
Exception 'first chance' à $762D5B68. Classe d'exception ERegistrationException avec un message 'Component type "uDAMemDataTable.TDAMemDataTable" incompatible with service type "SchemaClient_Intf.IEntiteType".'. Processus EntiteREM2.exe (3088)
Is there a way to override this check?
Ok I've found a way to do that. Super simple actually :
aContainer.RegisterType<IAddress>.DelegateTo(
function : IAddress
var aTable : TDAMemDataTable;
begin
aTable := TDAMemDataTable.Create(nil);
aTable.LogicalName := nme_Address;
aTable.BusinessRulesID := RID_Address;
Result := aTable as IAddress;
end
);
Also, for people interested in registering many tables in an elegant fashion :
aContainer.RegisterType<IAddress>.DelegateTo(TableConfigurator.GetTableDelegate<IAddress>(nme_Address, RID_Address));
// Registering other tables here...
Just create some "Helper" class with this method :
class function TableConfigurator.GetTableDelegate<T>(aLogicalName, aBusinessRulesId: string): TActivatorDelegate<T>;
begin
Result := (function: T
var
aTable: TDAMemDataTable;
begin
aTable := TDAMemDataTable.Create(nil);
aTable.LogicalName := aLogicalName;
aTable.BusinessRulesID := aBusinessRulesId;
Result := T(TValue.From(aTable).AsInterface);
end);
end;