First version of 'merge' method - used to create a UOW in case of updating a list of active records

samples/activerecord_showcase/EntitiesU.pas

@@ -124,6 +124,7 @@ type
   public
     constructor Create; override;
     destructor Destroy; override;
+    function ToString: String; override;
     property ID: NullableInt64 read fID write fID;
     property Code: NullableString read fCode write fCode;
     property CompanyName: NullableString read fCompanyName write fCompanyName;
@@ -436,6 +437,15 @@ begin
   inherited;
 end;
 
+function TCustomer.ToString: String;
+begin
+  Result := '';
+  if PKIsNull then
+    Result := '<null>';
+  Result := Format('[ID: %6s][CODE: %6s][CompanyName: %15s][City: %10s][Rating: %3d][Note: %s]',[
+    Result, fCode.ValueOrDefault, fCompanyName.ValueOrDefault, fCity, fRating.ValueOrDefault, fNote]);
+end;
+
 constructor TOrderDetail.Create;
 begin
   inherited Create;

samples/activerecord_showcase/MainFormU.dfm

@@ -2,7 +2,7 @@ object MainForm: TMainForm
   Left = 0
   Top = 0
   Caption = 'TMVCActiveRecord - ShowCase'
-  ClientHeight = 700
+  ClientHeight = 731
   ClientWidth = 635
   Color = clBtnFace
   Font.Charset = DEFAULT_CHARSET
@@ -15,7 +15,7 @@ object MainForm: TMainForm
   OnShow = FormShow
   DesignSize = (
     635
-    700)
+    731)
   PixelsPerInch = 96
   TextHeight = 13
   object btnCRUD: TButton
@@ -40,7 +40,7 @@ object MainForm: TMainForm
     Left = 135
     Top = 8
     Width = 492
-    Height = 684
+    Height = 715
     Anchors = [akLeft, akTop, akRight, akBottom]
     Ctl3D = True
     DoubleBuffered = True
@@ -194,6 +194,15 @@ object MainForm: TMainForm
     TabOrder = 17
     OnClick = btnJSON_XML_TypesClick
   end
+  object btnMerge: TButton
+    Left = 8
+    Top = 677
+    Width = 121
+    Height = 33
+    Caption = 'Merge'
+    TabOrder = 18
+    OnClick = btnMergeClick
+  end
   object FDConnection1: TFDConnection
     Left = 192
     Top = 56

samples/activerecord_showcase/MainFormU.pas

@@ -23,7 +23,8 @@ uses
   FireDAC.Stan.Async,
   FireDAC.Phys,
   FireDAC.VCLUI.Wait,
-  Data.DB, FireDAC.Comp.Client, MVCFramework.Nullables;
+  Data.DB, FireDAC.Comp.Client, MVCFramework.Nullables,
+  MVCFramework.ActiveRecord, System.Generics.Collections;
 
 type
   TMainForm = class(TForm)
@@ -46,6 +47,7 @@ type
     btnClientGeneratedPK: TButton;
     btnAttributes: TButton;
     btnJSON_XML_Types: TButton;
+    btnMerge: TButton;
     procedure btnCRUDClick(Sender: TObject);
     procedure btnInheritanceClick(Sender: TObject);
     procedure btnMultiThreadingClick(Sender: TObject);
@@ -66,9 +68,13 @@ type
     procedure btnClientGeneratedPKClick(Sender: TObject);
     procedure btnAttributesClick(Sender: TObject);
     procedure btnJSON_XML_TypesClick(Sender: TObject);
+    procedure btnMergeClick(Sender: TObject);
   private
     procedure Log(const Value: string);
     procedure LoadCustomers;
+    procedure Merge<T: TMVCActiveRecord>(CurrentList: TObjectList<T>; NewList: TObjectList<T>);
+    function KeyExists<T: TMVCActiveRecord>(const NewList: TObjectList<T>; const KeyValue: Integer;
+      out Index: Integer): Boolean;
   public
     { Public declarations }
   end;
@@ -81,14 +87,12 @@ implementation
 {$R *.dfm}
 
 uses
-  MVCFramework.ActiveRecord,
   EntitiesU,
   System.Threading,
-  System.Generics.Collections,
   MVCFramework.DataSet.Utils,
   MVCFramework.RQL.Parser,
   System.Math,
-  FDConnectionConfigU, EngineChoiceFormU;
+  FDConnectionConfigU, EngineChoiceFormU, System.Rtti;
 
 const
   Cities: array [0 .. 4] of string = ('Rome', 'New York', 'London', 'Melbourne', 'Berlin');
@@ -431,6 +435,43 @@ begin
   end;
 end;
 
+procedure TMainForm.btnMergeClick(Sender: TObject);
+var
+  lCustomer: TCustomer;
+  lCustomers: TObjectList<TCustomer>;
+  lCustomersChanges: TObjectList<TCustomer>;
+begin
+  TMVCActiveRecord.DeleteAll(TCustomer);
+  LoadCustomers;
+  lCustomers := TMVCActiveRecord.All<TCustomer>;
+  try
+    lCustomersChanges := TMVCActiveRecord.SelectRQL<TCustomer>('eq(city,"Rome")', 1000);
+    try
+      lCustomersChanges.Delete(0);
+      lCustomersChanges[1].CompanyName := 'Changed';
+      lCustomer := TCustomer.Create;
+      lCustomersChanges.Add(lCustomer);
+      lCustomer.Code := 'C8765';
+      lCustomer.CompanyName := 'New Company';
+      lCustomer.City := 'New City';
+      lCustomer.Rating := 3;
+
+      lCustomer := TCustomer.Create;
+      lCustomersChanges.Add(lCustomer);
+      lCustomer.Code := 'C9898';
+      lCustomer.CompanyName := 'New Company2';
+      lCustomer.City := 'New City2';
+      lCustomer.Rating := 5;
+
+      Merge<TCustomer>(lCustomers, lCustomersChanges);
+    finally
+      lCustomers.Free;
+    end;
+  finally
+    lCustomersChanges.Free;
+  end;
+end;
+
 procedure TMainForm.btnMultiThreadingClick(Sender: TObject);
 var
   lTasks: TArray<ITask>;
@@ -474,12 +515,11 @@ begin
       end;
     end;
 
-  lTasks := [
+  lTasks := [TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc),
     TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc),
     TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc),
     TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc),
-    TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc), TTask.Run(lProc)
-    ];
+    TTask.Run(lProc)];
   TTask.WaitForAll(lTasks);
 
   ShowMessage('Just inserted ' + TMVCActiveRecord.Count(TCustomer,
@@ -1249,8 +1289,7 @@ begin
 {$ELSE}
   Caption := Caption + ' WITHOUT SEQUENCES';
 {$ENDIF}
-  btnWithSpaces.Enabled :=
-    (ActiveRecordConnectionsRegistry.GetCurrentBackend = 'postgresql') or
+  btnWithSpaces.Enabled := (ActiveRecordConnectionsRegistry.GetCurrentBackend = 'postgresql') or
     (ActiveRecordConnectionsRegistry.GetCurrentBackend = 'firebird') or
     (ActiveRecordConnectionsRegistry.GetCurrentBackend = 'interbase') or
     (ActiveRecordConnectionsRegistry.GetCurrentBackend = 'sqlite');
@@ -1286,4 +1325,87 @@ begin
   Memo1.Update;
 end;
 
+function TMainForm.KeyExists<T>(const NewList: TObjectList<T>; const KeyValue: Integer;
+  out Index: Integer): Boolean;
+var
+  I: Integer;
+begin
+  Result := False;
+  for I := 0 to NewList.Count - 1 do
+  begin
+    if NewList[I].GetPK.AsInt64 = KeyValue then
+    begin
+      Index := I;
+      Exit(True);
+    end;
+  end;
+end;
+
+procedure TMainForm.Merge<T>(CurrentList, NewList: TObjectList<T>);
+var
+  lToDelete, lToUpdate, lToInsert: TObjectList<T>;
+  I: Integer;
+  lFoundAtIndex: Integer;
+  lCurrPKValue: Integer;
+  lPKValue: TValue;
+begin
+  lToDelete := TObjectList<T>.Create(False);
+  try
+    lToUpdate := TObjectList<T>.Create(False);
+    try
+      lToInsert := TObjectList<T>.Create(False);
+      try
+        lToDelete.AddRange(CurrentList);
+        for I := 0 to NewList.Count - 1 do
+        begin
+          if NewList[I].PKIsNull then
+          begin
+            lToInsert.Add(NewList[I]);
+            Continue;
+          end;
+          lCurrPKValue := NewList[I].GetPK.AsInteger;
+          if KeyExists<T>(CurrentList, lCurrPKValue, lFoundAtIndex) then
+          begin
+            // update
+            lToUpdate.Add(NewList[I]);
+            if KeyExists<T>(lToDelete, lCurrPKValue, lFoundAtIndex) then
+            begin
+              lToDelete.Delete(lFoundAtIndex);
+            end
+            else
+            begin
+              raise EMVCActiveRecordNotFound.CreateFmt
+                ('Cannot update a non existent record [PK: %s]', [lCurrPKValue.ToString]);
+            end;
+          end
+          else
+          begin
+            // insert
+            lToInsert.Add(NewList[I]);
+          end;
+        end;
+
+        for I := 0 to lToInsert.Count - 1 do
+        begin
+          Log('INSERT: ' + lToInsert[I].ToString);
+        end;
+        for I := 0 to lToUpdate.Count - 1 do
+        begin
+          Log('UPDATE: ' + lToUpdate[I].ToString);
+        end;
+        for I := 0 to lToDelete.Count - 1 do
+        begin
+          Log('DELETE: ' + lToDelete[I].ToString);
+        end;
+      finally
+        lToInsert.Free;
+      end;
+    finally
+      lToUpdate.Free;
+    end;
+  finally
+    lToDelete.Free;
+  end;
+end;
+
 end.

samples/commons/BusinessObjectsU.pas

@@ -2,7 +2,7 @@
 //
 // Delphi MVC Framework
 //
-// Copyright (c) 2010-2020 Daniele Teti and the DMVCFramework Team
+// Copyright (c) 2010-2021 Daniele Teti and the DMVCFramework Team
 //
 // https://github.com/danieleteti/delphimvcframework
 //

sources/MVCFramework.ActiveRecord.pas

@@ -282,6 +282,8 @@ type
     procedure SetPropertyValue(const aProp: TRttiProperty; const aValue: TValue);
     function GetPK: TValue;
     function TryGetPKValue(var Value: TValue; out IsNullableType: Boolean): Boolean;
+    function PKIsNullable(out PKValue: TValue): Boolean;
+    function PKIsNull: Boolean;
     procedure AddChildren(const ChildObject: TObject);
     procedure RemoveChildren(const ChildObject: TObject);
     // dynamic access
@@ -1293,6 +1295,25 @@ begin
   end;
 end;
 
+function TMVCActiveRecord.PKIsNull: Boolean;
+var
+  lValue: TValue;
+  lIsNullableType: Boolean;
+begin
+  if not PKIsNullable(lValue) then
+  begin
+    raise EMVCActiveRecord.Create('PK is not nullable');
+  end;
+  Result := not TryGetPKValue(lValue, lIsNullableType);
+end;
+
+function TMVCActiveRecord.PKIsNullable(out PKValue: TValue): Boolean;
+var
+  lValue: TValue;
+begin
+  PKValue := TryGetPKValue(lValue, Result);
+end;
+
 function TMVCActiveRecord.GetPrimaryKeyFieldType: TFieldType;
 begin
   Result := fPrimaryKeyFieldType;