Dynamic marshaling from sql

[Ismet Sonmez]

Hi,

I tested this code, work good.For dynamic object creation and marshaling.

Is that true way or is there any other way?

unit MainObject;

interface
uses SysUtils, Generics.Collections, Rtti,
kbmMemTable,
kbmMWRTTI,
kbmMWObjectMarshal,
kbmMWJSONMarshal,
kbmMWXMLMarshal,
kbmMWYAMLMarshal,
MainDbModule;

type

TBaseObjectClass = class of TBaseObject;
TBaseObject = class
end;

[kbmMW_Root(‘Result’,[mwrfIncludeOnlyTagged])]
TResult = class(TBaseObject)
private
FCode : integer;
FDesc : string;
public
[kbmMW_Attribute(‘Code’)]
property Code : integer read FCode write FCode;
[kbmMW_Attribute(‘Desc’)]
property Desc : string read FDesc write FDesc;
end;

[kbmMW_Root(‘SimpleObject’,[mwrfIncludeOnlyTagged])]
TSimpleObject = class(TBaseObject)
private
FObjId: Int64;
FCode : string;
FDesc : string;
public
[kbmMW_Attribute(‘ObjId’)]
property ObjId : Int64 read FObjId write FObjId;
[kbmMW_Attribute(‘Code’)]
property Code : string read FCode write FCode;
[kbmMW_Attribute(‘Desc’)]
property Desc : string read FDesc write FDesc;
end;

[kbmMW_Root(‘SimpleObjectResult’,[mwrfIncludeOnlyTagged])]
TSimpleObjectResult = class(TResult)
private
FData : TSimpleObject;
public
destructor Destroy(); override;
[kbmMW_Attribute(‘Data’)]
property Data : TSimpleObject read FData write FData;
end;

function ObjectMarshal(AClass:TBaseObject; AType: Integer=1; AAnonymousRoot: Boolean=False; AModifiedStatus: Boolean=False; AJQueryEscapes: Boolean=False; AAlignChildren: Boolean=False): string;
function ObjectUnMarshal(ABaseObjectClass:TBaseObjectClass; AObjectString: string; AType: Integer=1; AAnonymousRoot: Boolean=False; AModifiedStatus: Boolean=False; AJQueryEscapes: Boolean=False):TBaseObject;
function GetSimpleObjectBySql(const ASql: string):TSimpleObject;
function GetSimpleObjectResultBySql(const ASql: string):TSimpleObjectResult;

implementation

function ObjectMarshal(AClass:TBaseObject; AType: Integer=1; AAnonymousRoot: Boolean=False; AModifiedStatus: Boolean=False; AJQueryEscapes: Boolean=False; AAlignChildren: Boolean=False): string;
var
m:TkbmMWCustomRTTIMarshal;
begin
Result := ”;
case AType of
1 : begin // JSON
m := TkbmMWJSONMarshal.Create;
try
TkbmMWJSONMarshal(m).Typed := false;
TkbmMWJSONMarshal(m).AutoIndent := true;
TkbmMWJSONMarshal(m).AutoLineFeed := true;
TkbmMWJSONMarshal(m).JQueryEscaping := AJQueryEscapes;
TkbmMWJSONMarshal(m).AnonymousRoot := AAnonymousRoot;
m.IncludeModifiedStatus := AModifiedStatus;
m.ExceptOnUnknownType := true;
Result := TkbmMWJSONMarshal(m).ValueToString(AClass);
finally
m.Free;
end;
end;
2 : begin // XML
m := TkbmMWXMLMarshal.Create;
try
TkbmMWXMLMarshal(m).Typed := false;
TkbmMWXMLMarshal(m).AutoIndent := true;
TkbmMWXMLMarshal(m).AutoLineFeed := true;
TkbmMWXMLMarshal(m).PreserveWhiteSpace := false;
m.IncludeModifiedStatus := AModifiedStatus;
m.ExceptOnUnknownType := true;
Result := TkbmMWXMLMarshal(m).ValueToString(AClass);
finally
m.Free;
end;
end;
3 : begin // YAML
m := TkbmMWYAMLMarshal.Create;
try
TkbmMWYAMLMarshal(m).Typed := false;
TkbmMWYAMLMarshal(m).Indentation := 2;
TkbmMWYAMLMarshal(m).AnonymousRoot := AAnonymousRoot;
TkbmMWYAMLMarshal(m).AlignChildren := AAlignChildren;
m.IncludeModifiedStatus := AModifiedStatus;
m.ExceptOnUnknownType := true;
Result := TkbmMWYAMLMarshal(m).ValueToString(AClass);
finally
m.Free;
end;
end;
end;
end;

function ObjectUnMarshal(ABaseObjectClass:TBaseObjectClass; AObjectString: string; AType: Integer=1; AAnonymousRoot: Boolean=False; AModifiedStatus: Boolean=False; AJQueryEscapes: Boolean=False):TBaseObject;
var
m:TkbmMWCustomRTTIMarshal;
begin
Result := nil;
case AType of
1 : begin // JSON
m:=TkbmMWJSONMarshal.Create;
try
m.ExceptOnUnknownType := True;
m.IncludeModifiedStatus := AModifiedStatus;
TkbmMWJSONMarshal(m).JQueryEscaping := AJQueryEscapes;
TkbmMWJSONMarshal(m).AnonymousRoot := AAnonymousRoot;
Result := TBaseObject(TkbmMWJSONMarshal(m).ValueFromString(ABaseObjectClass,AObjectString));
finally
m.Free;
end;
end;
2 : begin // XML
m:=TkbmMWXMLMarshal.Create;
try
m.ExceptOnUnknownType := True;
m.IncludeModifiedStatus := AModifiedStatus;
Result := TBaseObject(TkbmMWXMLMarshal(m).ValueFromString(ABaseObjectClass,AObjectString));
finally
m.Free;
end;
end;
3 : begin // YAML
m:=TkbmMWYAMLMarshal.Create;
try
m.ExceptOnUnknownType:=true;
m.IncludeModifiedStatus := AModifiedStatus;
Result := TBaseObject(TkbmMWYAMLMarshal(m).ValueFromString(ABaseObjectClass,AObjectString));
finally
m.Free;
end;
end;
end;
end;

function GetSimpleObjectBySql(const ASql: string):TSimpleObject;
var
mtTemp:TKbmMemTable;
begin
Result:=TSimpleObject.Create();
Result.ObjId := -1;
Result.Code := ”;
Result.Desc := ”;
mtTemp := TKbmMemTable.Create(nil);
try
ModuleMainDB.LoadQuery(mtTemp, ASql);
if (mtTemp.Active) and (mtTemp.RecordCount = 1) then
begin
Result.ObjId := mtTemp.FieldByName(‘OBJID’).AsInteger;
Result.Code := mtTemp.FieldByName(‘CODE’).AsString;
Result.Desc := mtTemp.FieldByName(‘DESCRIPTION’).AsString;
end;
mtTemp.Close;
finally
mtTemp.Free;
end;
end;

function GetSimpleObjectResultBySql(const ASql: string):TSimpleObjectResult;
begin
Result := TSimpleObjectResult.Create();
Result.Code := 1001 ;
Result.Desc := ‘NA’ ;
try
Result.Data := GetSimpleObjectBySql(ASql);
if Result.Data.ObjId = -1 then
begin
Result.Code := 1003;
Result.Desc := ‘Kayıt bulunamadı’;
FreeAndNil(Result.Data);
end else
begin
Result.Code := 1000;
Result.Desc := ‘SUCC’;
end;
except
On E :Exception do begin
Result.Code := 1002;
Result.Desc := ‘Kod bloğunda hata oluştu’; // E.Message;
end;
end;
end;

destructor TSimpleObjectResult.Destroy;
begin
if FData<>nil then
FData.Free;
inherited;
end;

initialization

kbmMWRegisterKnownTypes([
typeinfo(TBaseObject),
typeinfo(TResult),
typeinfo(TSimpleObject),
typeinfo(TSimpleObjectResult)
]);
end.

 

 

 

[Ismet Sonmez]

test code;

procedure TFormMain.Button1Click(Sender: TObject);
var
o:TSimpleObjectResult;
s:TSimpleObjectResult;
str:string;
begin
s := GetSimpleObjectResultBySql(‘SELECT * FROM SYSFIRM’);

str := ObjectMarshal(S,1,True);
showmessage(str);

o:=TSimpleObjectResult(ObjectUnMarshal(TSimpleObjectResult,str,1,True));
showmessage(o.Data.Desc);
end;

[kimbomadsen]

Hi,

Well there are many ways to enter data into objects.

Marshalling is one of them. The rulebook for marshalling is usually a Delphi class as you have done it.
The Delphi class can be handcoded as you did, or autogenerated from an XSD if you prefer that method. kbmMW supports both.

If your data comes from a SQL statement, you could use kbmMW’s ORM to access the data, then you will automatically have Delphi objects rather than a dataset, and you will not need to do any manual copying of data from the SQL dataset to new object instances.

Further you could choose to use kbmMW’s SmartService REST features, then you also do not need to do any marshalling yourself. It will automatically be done for you, both for data provided to the REST function, and the resulting data returned from the REST function.

Check the blog series REST easy which explains that in quite some detail.
/Kim

[Author]

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