// TORMBind_Component_QryRec_Dictionary is used to map each TQryRecInfo descendant property to its respective TComponent, for example:

TEmployee1 is an instance of a TQryRecInfo descendant.

* a TLabel TComponent "EmpName" maps to the property "EmployeeName" of TEmployee1
* a TLabel TComponent "EmpSalary" maps to the property "Salary" of TEmployee1
* a TDatePicker TComponent "BirthDay" maps to the property "DateOfBirth" of TEmployee1

For TEmployee1 I want choose to "bind" some of its properties to the corresponding TComponent that I choose, like the above example.
Something like:
TEmployee1.Bind('EmployeeName', EmpName);
TEmployee1.Bind('Salary', EmpSalary);
TEmployee1.Bind('DateOfBirth', BirthDay);

I need this to operate to perform bidirectional update, following some rules:
if the TQryRecInfo descendant property is mapped to a TEdit, then this property maps to the TEdit.Text
if the TQryRecInfo descendant property is mapped to a TLabel, then this property maps to the TLabel.Caption
if the TQryRecInfo descendant property is mapped to a TDatePicker, then this property maps to the TDatePicker.Date
and so on...

When the TQryRecInfo descendant property is not a string, but it should map to a string TComponent property, then use GetFormattedText to convert to its string representation 


Then create some methods to perform the bidirectional binding between the TComponent property changes and its corresponding TQryRecInfo descendant property.
Create methods to Bind and Unbind manually.
Also create methods to bind all the TQryRecInfo descendant properties to the respective TComponents that have matching Hint contents to the TQryRecInfo descendant property name.


Perform the mapping using something like:

type
 TComponentMapping = record
  Mapped_TQryRecInfo_Instance: TObject;
  Mapped_Property: string;
 end;

type
 TORMBind_Component_QryRec_Dictionary = TDictionary<TComponent, TComponentMapping>;

------------

unit pixel_classes;

interface

uses
 System.SysUtils, Rtti, TypInfo;

{$TYPEINFO ON}

type
 TZString = type string;

type
  TNullValue = record
  end;

  TNullable<T{: record}> = record
  public
    Value: T;
    HasValue: Boolean;

    class operator Implicit(const AValue: T): TNullable<T>;
    class operator Implicit(const AValue: TNullable<T>): T;
    class operator Implicit(const AValue: TNullValue): TNullable<T>;
    class operator Explicit(const AValue: T): TNullable<T>;

    // add these...
    class operator Equal(const A: TNullable<T>; const B: TNullValue): Boolean;
    class operator NotEqual(const A: TNullable<T>; const B: TNullValue): Boolean;
  end;

var NullValue: TNullValue;

implementation

class operator TNullable<T>.Implicit(const AValue: T): TNullable<T>;
begin
  Result.Value := AValue;
  Result.HasValue := True;
end;

class operator TNullable<T>.Implicit(const AValue: TNullable<T>): T;
begin
  if AValue.HasValue then
    Result := AValue.Value
  else
    Result := Default(T); // or raise an exception
end;

class operator TNullable<T>.Implicit(const AValue: TNullValue): TNullable<T>;
begin
  Result.Value := Default(T);
  Result.HasValue := False;
end;

class operator TNullable<T>.Explicit(const AValue: T): TNullable<T>;
begin
  Result.Value := AValue;
  Result.HasValue := True;
end;

class operator TNullable<T>.Equal(const A: TNullable<T>; const B: TNullValue): Boolean;
begin
  Result := not A.HasValue;
end;

class operator TNullable<T>.NotEqual(const A: TNullable<T>; const B: TNullValue): Boolean;
begin
  Result := A.HasValue;
end;

end.

------------

unit ORM_CustomAttributes;

{$TYPEINFO ON}

interface

uses
  System.SysUtils, System.Classes, System.Rtti;

type
  TFormatType = (tiString, tiInteger, tiDate, tiDateTime, tiMoney, tiFloat, tiBoolean, tiByteArray, tiNone);

  /// <summary>
  /// Attribute to specify the database table associated with a class or field.
  /// </summary>
  TableAttribute = class(TCustomAttribute)
  private
    FTableName: string;
  public
    constructor Create(const ATableName: string);
    property TableName: string read FTableName;
  end;

  /// <summary>
  /// Attribute to mark a field as a primary key.
  /// </summary>
  PrimaryKeyAttribute = class(TCustomAttribute)
  public
    constructor Create;
  end;

  /// <summary>
  /// Attribute to specify the database column associated with a field.
  /// </summary>
  RefColumnAttribute = class(TCustomAttribute)
  private
    FColumnName: string;
  public
    constructor Create(const AColumnName: string);
    property ColumnName: string read FColumnName;
  end;

  /// <summary>
  /// Attribute to specify the formatting of a field.
  /// </summary>
  FmtPropAttribute = class(TCustomAttribute)
  private
    FFormatType: TFormatType;
  public
    constructor Create(AFormatType: TFormatType);
    property FormatType: TFormatType read FFormatType;
  end;

  /// <summary>
  /// Attribute to specify the column index of a property in a TStringGrid.
  /// </summary>
  GridColumnAttribute = class(TCustomAttribute)
  private
    FColumnIndex: Integer;
  public
    constructor Create(AColumnIndex: Integer);
    property ColumnIndex: Integer read FColumnIndex;
  end;

  /// <summary>
  /// Attribute to specify the TComponent a property is mapped to.
  /// </summary>
  ComponentMappingAttribute = class(TCustomAttribute)
  private
    FComponentName: string;
  public
    constructor Create(const AComponentName: string);
    property ComponentName: string read FComponentName;
  end;

implementation

{ TableAttribute }

constructor TableAttribute.Create(const ATableName: string);
begin
  inherited Create;
  FTableName := ATableName;
end;

{ RefColumnAttribute }

constructor RefColumnAttribute.Create(const AColumnName: string);
begin
  inherited Create;
  FColumnName := AColumnName;
end;

{ PrimaryKeyAttribute }

constructor PrimaryKeyAttribute.Create;
begin
  inherited Create;
end;

{ FmtPropAttribute }

constructor FmtPropAttribute.Create(AFormatType: TFormatType);
begin
  inherited Create;
  FFormatType := AFormatType;
end;

{ GridColumnAttribute }

constructor GridColumnAttribute.Create(AColumnIndex: Integer);
begin
  inherited Create;
  FColumnIndex := AColumnIndex;
end;

{ ComponentMappingAttribute }

constructor ComponentMappingAttribute.Create(const AComponentName: string);
begin
  inherited Create;
  FComponentName := AComponentName;
end;

end.

------------

unit orm_utils;

interface

uses
  System.SysUtils,
  System.Classes,
  System.Generics.Collections,
  System.Rtti,
  System.TypInfo,
  Data.DB,
  Uni,
  VCL.Grids, // for TAdvStringGrid
  AdvGrid,  // for TAdvStringGrid
  Vcl.Controls,
  Vcl.StdCtrls,
  pixel_classes,
  orm_customattributes;

type
  EORMUtilsException = class(Exception);

  /// <summary>
  /// Base class for query record information
  /// Use descendants of this class to represent specific database records.
  /// </summary>
  TQryRecInfo = class
  private
    FDirtyFields: TDictionary<string, Boolean>;
    FPreviousValues: TDictionary<string, TValue>;
    FComponents: TDictionary<string, TComponent>;
    procedure SetInfo(Index: Integer; const Value: TValue);
    procedure UpdateComponent(const PropName: string; const Value: TValue);
    procedure UpdateComponents;
  public
    constructor Create;
    destructor Destroy; override;

    // Methods to set nullable fields
    procedure SetInfoNullableString(Index: Integer; const Value: TNullable<string>);
    procedure SetInfoNullableInteger(Index: Integer; const Value: TNullable<Integer>);
    procedure SetInfoNullableInt64(Index: Integer; const Value: TNullable<Int64>);
    procedure SetInfoNullableExtended(Index: Integer; const Value: TNullable<Extended>);
    procedure SetInfoNullableCurrency(Index: Integer; const Value: TNullable<Currency>);
    procedure SetInfoNullableDateTime(Index: Integer; const Value: TNullable<TDateTime>);
    procedure SetInfoNullableBoolean(Index: Integer; const Value: TNullable<Boolean>);
    procedure SetInfoNullableVariant(Index: Integer; const Value: TNullable<Variant>);

    // Methods to set non-nullable simple types
    procedure SetInfoCurrency(Index: Integer; const Value: Currency);
    procedure SetInfoString(Index: Integer; const Value: string);
    procedure SetInfoInteger(Index: Integer; const Value: Integer);
    procedure SetInfoInt64(Index: Integer; const Value: Int64);
    procedure SetInfoExtended(Index: Integer; const Value: Extended);
    procedure SetInfoDateTime(Index: Integer; const Value: TDateTime);
    procedure SetInfoBoolean(Index: Integer; const Value: Boolean);
    procedure SetInfoVariant(Index: Integer; const Value: Variant);

    // Methods to handle dirty fields
    function IsFieldDirty(const FieldName: string): Boolean;
    procedure ClearDirtyFlags;
    property DirtyFields: TDictionary<string, Boolean> read FDirtyFields;

    // Methods to handle previous values
    function GetPreviousValue(const FieldName: string): TValue;
    procedure ClearPreviousValues;
    property PreviousValues: TDictionary<string, TValue> read FPreviousValues;

    // Method to handle mapping to components
    procedure MapToComponent(const PropName: string; Component: TComponent);

    /// <summary>
    /// Retrieves the formatted text for a given field based on the FmtProp attribute.
    /// </summary>
    function GetFormattedText(const FieldName: string): string;

    /// <summary>
    /// Fetches data for this record from the database based on the provided SQL.
    /// </summary>
    procedure Fetch(DBConn: TUniConnection; const QryTxt: string);
  end;

  /// <summary>
  /// Generic class to handle arrays of TQryRecInfo descendants.
  /// </summary>
  TQryRecArray<T: class, constructor> = class
  private
    FQryRecInfoList: TObjectList<T>;
    FFilterSQL: string;
    FDBConn: TUniConnection;
    FGrid: TAdvStringGrid;
    FColumnMapping: TDictionary<string, Integer>;
    function GetCount: Integer;
    procedure UpdateGrid;
    procedure GridToRecInfo(ACol, ARow: Integer);
  public
    constructor Create;
    destructor Destroy; override;

    /// <summary>
    /// Fetches all records based on the provided SQL text and populates the array.
    /// </summary>
    /// <param name="QryTxt">The base SQL query text.</param>
    procedure FetchAllInstance(DBConn: TUniConnection; const QryTxt: string);

    /// <summary>
    /// Clears any SQL filters applied.
    /// </summary>
    procedure ClearFilter;

    /// <summary>
    /// Accesses a record at the specified index.
    /// </summary>
    /// <param name="Index">The zero-based index of the record.</param>
    /// <returns>The record at the specified index.</returns>
    function Rec(Index: Integer): T;

    /// <summary>
    /// Number of records in the array.
    /// </summary>
    property RecCount: Integer read GetCount;

    /// <summary>
    /// Database connection used for fetching records.
    /// </summary>
    property DBConn: TUniConnection read FDBConn write FDBConn;

    /// <summary>
    /// Map of property names to specific grid columns by name.
    /// </summary>
    procedure MapToGrid(AGrid: TAdvStringGrid; const PropName: string; const ColumnName: string);

    /// <summary>
    /// Additional SQL filter to apply to the query.
    /// </summary>
    property SQLFilter: string read FFilterSQL write FFilterSQL;

    /// <summary>
    /// Provides support for for-in loops by returning an enumerator.
    /// </summary>
    function GetEnumerator: TEnumerator<T>;

    /// <summary>
    /// Factory method to create and fetch records in a single step.
    /// </summary>
    /// <param name="DBConn">Database connection.</param>
    /// <param name="QryTxt">SQL query text.</param>
    /// <returns>Populated instance of TQryRecArray<T>.</returns>
    class function FetchAll(DBConn: TUniConnection; const QryTxt: string): TQryRecArray<T>; static;
  end;

  // Example descendant of TQryRecInfo (You can create your own)
  TDynRec = class(TQryRecInfo)
    // Define additional properties as needed
  end;

implementation

uses
  System.Variants,
  StrUtils,
  pixel_utils; // Ensure this unit is in your project and properly implemented

{ TQryRecInfo }

constructor TQryRecInfo.Create;
begin
  inherited Create;
  FDirtyFields := TDictionary<string, Boolean>.Create;
  FPreviousValues := TDictionary<string, TValue>.Create;
  FComponents := TDictionary<string, TComponent>.Create;
end;

destructor TQryRecInfo.Destroy;
begin
  FDirtyFields.Free;
  FPreviousValues.Free;
  FComponents.Free;
  inherited;
end;

procedure TQryRecInfo.ClearDirtyFlags;
begin
  FDirtyFields.Clear;
end;

procedure TQryRecInfo.ClearPreviousValues;
begin
  FPreviousValues.Clear;
end;

function TQryRecInfo.IsFieldDirty(const FieldName: string): Boolean;
begin
  Result := FDirtyFields.ContainsKey(FieldName) and FDirtyFields[FieldName];
end;

function TQryRecInfo.GetPreviousValue(const FieldName: string): TValue;
begin
  if not FPreviousValues.TryGetValue(FieldName, Result) then
    raise EORMUtilsException.CreateFmt('No previous value found for field "%s".', [FieldName]);
end;

function FormataInfo(info: Variant; tipo: TFormatType): string;
begin
  if VarIsNull(info) or VarIsEmpty(info) then
    Exit('');

  case tipo of
    tiString:
      Result := VarToStr(info);
    tiInteger:
      Result := IntToStr(Integer(info));
    tiMoney:
      Result := FormatFloat(FMT_MONEY, Currency(info));
    tiFloat:
      Result := FloatToStr(info);
    tiDate:
      if VarIsType(info, [varDate, varDouble]) then
      begin
        if VarToDateTime(info) < EncodeDate(1900, 1, 1) then
          Result := ''
        else
          Result := FormatDateTime('dd/mm/yyyy', VarToDateTime(info));
      end
      else
        raise EORMUtilsException.CreateFmt('FormataInfo: Cannot treat information [%s] as tiDate.', [VarToStr(info)]);
    tiDateTime:
      if VarIsType(info, [varDate, varDouble]) then
      begin
        if VarToDateTime(info) = 0 then
          Result := ''
        else
          Result := FormatDateTime('dd/mm/yyyy hh:mm:ss', VarToDateTime(info));
      end
      else
        raise EORMUtilsException.CreateFmt('FormataInfo: Cannot treat information [%s] as tiDateTime.', [VarToStr(info)]);
    tiBoolean:
      Result := IfThen(Boolean(info), 'S', 'N');
    tiByteArray:
      Result := ByteArrayToHex(info);
    tiNone:
      Result := '';
  else
    raise EORMUtilsException.CreateFmt('FormataInfo: Format type [%s] not recognized.', [GetEnumName(TypeInfo(TFormatType), Integer(tipo))]);
  end;
end;

function TQryRecInfo.GetFormattedText(const FieldName: string): string;
var
  Ctx: TRttiContext;
  RttiType: TRttiType;
  Prop: TRttiProperty;
  Field: TRttiField;
  Value: TValue;
  FmtType: TFormatType;
  UnderlyingType: TRttiType;
  HasValueField: TRttiField;
  ValueField: TRttiField;
  HasValue: Boolean;
  ActualValue: TValue;
  Attr: TCustomAttribute;
  FmtAttr: FmtPropAttribute;
begin
  Result := '';
  Ctx := TRttiContext.Create;
  try
    RttiType := Ctx.GetType(Self.ClassType);

    // Find the property by name
    Prop := RttiType.GetProperty(FieldName);
    if not Assigned(Prop) then
      raise EORMUtilsException.CreateFmt('Property "%s" not found.', [FieldName]);

    // Get the value of the property
    Value := Prop.GetValue(Self);
    FmtType := tiNone;

    // Check for FmtProp attribute on the property
    for Attr in Prop.GetAttributes do
    begin
      if Attr is FmtPropAttribute then
      begin
        FmtAttr := FmtPropAttribute(Attr);
        FmtType := FmtAttr.FormatType;
        Break;
      end;
    end;

    // If not found on property, check on the corresponding field
    if FmtType = tiNone then
    begin
      Field := RttiType.GetField('_' + FieldName);
      if Assigned(Field) then
      begin
        for Attr in Field.GetAttributes do
        begin
          if Attr is FmtPropAttribute then
          begin
            FmtAttr := FmtPropAttribute(Attr);
            FmtType := FmtAttr.FormatType;
            Break;
          end;
        end;
      end;
    end;

    // Determine default FmtType based on property type if not set by attribute
    if FmtType = tiNone then
    begin
      UnderlyingType := Prop.PropertyType;

      // Handle TNullable<T>
      if UnderlyingType.TypeKind = tkRecord then
      begin
        ValueField := UnderlyingType.GetField('Value');
        if Assigned(ValueField) then
          UnderlyingType := ValueField.FieldType;
      end;

      case UnderlyingType.TypeKind of
        tkInteger, tkInt64:
          FmtType := tiInteger;
        tkFloat:
          if UnderlyingType.Handle = TypeInfo(TDateTime) then
            FmtType := tiDateTime
          else
            FmtType := tiFloat;
        tkString, tkLString, tkWString, tkUString:
          FmtType := tiString;
        tkEnumeration:
          if UnderlyingType.Handle = TypeInfo(Boolean) then
            FmtType := tiBoolean
          else
            FmtType := tiString;
        tkVariant:
          FmtType := tiString;
      else
        FmtType := tiNone;
      end;
    end;

    // Extract actual value from TNullable<T> if necessary
    if Value.Kind = tkRecord then
    begin
      // Assuming TNullable<T> has 'HasValue' and 'Value' fields
      UnderlyingType := Prop.PropertyType;
      HasValueField := UnderlyingType.GetField('HasValue');
      ValueField := UnderlyingType.GetField('Value');

      if Assigned(HasValueField) and Assigned(ValueField) then
      begin
        HasValue := HasValueField.GetValue(Value.GetReferenceToRawData).AsBoolean;
        if HasValue then
        begin
          ActualValue := ValueField.GetValue(Value.GetReferenceToRawData);
          // Format the actual value
          Result := FormataInfo(ActualValue.AsVariant, FmtType);
        end
        else
          Result := '';
      end
      else
      begin
        // Not TNullable<T>, handle value directly
        if not Value.IsEmpty then
          Result := FormataInfo(Value.AsVariant, FmtType)
        else
          Result := '';
      end;
    end
    else
    begin
      // Not a record, handle value directly
      if not Value.IsEmpty then
        Result := FormataInfo(Value.AsVariant, FmtType)
      else
        Result := '';
    end;
  finally
    // No need to free TRttiContext as it's a record
  end;
end;

procedure TQryRecInfo.UpdateComponent(const PropName: string; const Value: TValue);
var
  Component: TComponent;
begin
  if FComponents.TryGetValue(PropName, Component) then
  begin
    if Component is TEdit then
      TEdit(Component).Text := Value.ToString
    else if Component is TLabel then
      TLabel(Component).Caption := Value.ToString
    else if Component is TButton then
      TButton(Component).Caption := Value.ToString;
    // Add more component types if necessary
  end;
end;

procedure TQryRecInfo.UpdateComponents;
var
  PropName: string;
  Value: TValue;
  Ctx: TRttiContext;
  RttiType: TRttiType;
  RttiProp: TRttiProperty;
begin
  Ctx := TRttiContext.Create;
  try
    RttiType := Ctx.GetType(Self.ClassType);
    if RttiType <> nil then
    begin
      for PropName in FComponents.Keys do
      begin
        RttiProp := RttiType.GetProperty(PropName);
        if (RttiProp <> nil) and (RttiProp.Visibility = mvPublished) then
        begin
          if RttiProp.PropertyType.TypeKind = tkClass then
          begin
            Value := RttiProp.GetValue(Self);
            UpdateComponent(PropName, Value);
          end
          else
            // Handle other property types or log a message
        end;
      end;
    end;
  finally
    Ctx.Free;
  end;
end;

procedure TQryRecInfo.Fetch(DBConn: TUniConnection; const QryTxt: string);
var
  qr: TUniQuery;
  Ctx: TRttiContext;
  ObjType: TRttiType;
  Prop: TRttiProperty;
  Field: TField;
  ORMFieldName: string;
begin
  if not Assigned(DBConn) or Trim(QryTxt).IsEmpty then
    Exit;

  qr := TUniQuery.Create(nil);
  try
    qr.Connection := DBConn;
    qr.SpecificOptions.Values['FetchAll'] := 'True';
    qr.SpecificOptions.Values['CreateConnection'] := 'False';
    qr.SQL.Text := QryTxt;
    qr.Open;

    if qr.RecordCount > 0 then
    begin
      Ctx := TRttiContext.Create;
      try
        ObjType := Ctx.GetType(Self.ClassType);

        for Prop in ObjType.GetProperties do
        begin
          if not Prop.IsWritable then
            Continue;

          // Attempt to find the corresponding field in the query
          Field := qr.FindField(Prop.Name);
          if not Assigned(Field) then
            Continue; // Field not found, skip

          ORMFieldName := '_' + Prop.Name;
          // Handle TNullable<T> types
          if Prop.PropertyType.TypeKind = tkRecord then
          begin
            // Expecting TNullable<T>
            // Attempt to find the backing field for the nullable property
            if ObjType.GetField(ORMFieldName) = nil then
              Continue; // Backing field not found, skip

            if Prop.PropertyType.Name.StartsWith('TNullable<') then
            begin
              // Use RTTI to determine the generic type parameter
              if Field.IsNull then
                ObjType.GetField(ORMFieldName).SetValue(Self, TValue.From<TNullable<Variant>>(NullValue))
              else
              begin
                if Prop.PropertyType.Name = 'TNullable<System.string>' then
                  ObjType.GetField(ORMFieldName).SetValue(Self, TValue.From<TNullable<string>>(Field.AsString))
                else if Prop.PropertyType.Name = 'TNullable<System.Integer>' then
                  ObjType.GetField(ORMFieldName).SetValue(Self, TValue.From<TNullable<Integer>>(Field.AsInteger))
                else if Prop.PropertyType.Name = 'TNullable<System.Int64>' then
                  ObjType.GetField(ORMFieldName).SetValue(Self, TValue.From<TNullable<Int64>>(Field.AsLargeInt))
                else if Prop.PropertyType.Name = 'TNullable<System.Extended>' then
                  ObjType.GetField(ORMFieldName).SetValue(Self, TValue.From<TNullable<Extended>>(Field.AsFloat))
                else if Prop.PropertyType.Name = 'TNullable<System.Currency>' then
                  ObjType.GetField(ORMFieldName).SetValue(Self, TValue.From<TNullable<Currency>>(Field.AsCurrency))
                else if Prop.PropertyType.Name = 'TNullable<System.TDateTime>' then
                  ObjType.GetField(ORMFieldName).SetValue(Self, TValue.From<TNullable<TDateTime>>(Field.AsDateTime))
                else if Prop.PropertyType.Name = 'TNullable<System.Boolean>' then
                  ObjType.GetField(ORMFieldName).SetValue(Self, TValue.From<TNullable<Boolean>>(Field.AsBoolean))
                else if Prop.PropertyType.Name = 'TNullable<System.Variant>' then
                  ObjType.GetField(ORMFieldName).SetValue(Self, TValue.From<TNullable<Variant>>(Field.Value))
                else
                  raise EORMUtilsException.CreateFmt('Unsupported TNullable type: %s', [Prop.PropertyType.Name]);
              end;
            end
            else
              raise EORMUtilsException.CreateFmt('Unsupported record type: %s', [Prop.PropertyType.Name]);
          end
          else
          begin
            // Handle non-nullable types
            case Prop.PropertyType.TypeKind of
              tkString, tkLString, tkWString, tkUString:
                ObjType.GetField(ORMFieldName).SetValue(Self, Field.AsString);
              tkInteger:
                ObjType.GetField(ORMFieldName).SetValue(Self, Field.AsInteger);
              tkInt64:
                ObjType.GetField(ORMFieldName).SetValue(Self, Field.AsLargeInt);
              tkFloat:
                if Prop.PropertyType.Handle = TypeInfo(Currency) then
                  ObjType.GetField(ORMFieldName).SetValue(Self, Field.AsCurrency)
                else
                  ObjType.GetField(ORMFieldName).SetValue(Self, Field.AsFloat);
              tkVariant:
                ObjType.GetField(ORMFieldName).SetValue(Self, TValue.FromVariant(Field.AsVariant));
              tkEnumeration:
                if Prop.PropertyType.Handle = TypeInfo(Boolean) then
                  ObjType.GetField(ORMFieldName).SetValue(Self, Field.AsBoolean)
                else
                  raise EORMUtilsException.CreateFmt('Unsupported enumeration type: %s', [Prop.PropertyType.Name]);
            else
              // Add additional handling for other types if necessary
            end;
          end;
        end;
      finally
        // No need to free TRttiContext as it's a record
      end;
      UpdateComponents;
    end;
  finally
    qr.Free;
  end;
end;

procedure TQryRecInfo.SetInfo(Index: Integer; const Value: TValue);
var
  PropName: string;
  PropKind: TTypeKind;
  Ctx: TRttiContext;
  Prop: TRttiProperty;
  Field: TRttiField;
  OldValue: TValue;
begin
  // Retrieve property name and kind based on index
  // Assuming that the index corresponds to the property order
  Ctx := TRttiContext.Create;
  try
    Prop := Ctx.GetType(Self.ClassType).GetProperties()[Index];
    if not Assigned(Prop) then
      raise EORMUtilsException.CreateFmt('Error: The index "%d" does not correspond to any property in class "%s".', [Index, ClassName]);

    PropName := Prop.Name;
    PropKind := Prop.PropertyType.TypeKind;

    Field := Ctx.GetType(Self.ClassType).GetField('_' + PropName);
    if not Assigned(Field) then
      raise EORMUtilsException.CreateFmt('Error: Field "_%s" not found in class "%s".', [PropName, ClassName]);

    // If the field is not yet dirty, store the previous value
    if not FDirtyFields.ContainsKey(PropName) then
    begin
      OldValue := Field.GetValue(Self);
      FPreviousValues.AddOrSetValue(PropName, OldValue);
    end;

    // Set the new value
    Field.SetValue(Self, Value);

    // Mark the property as dirty
    FDirtyFields.AddOrSetValue(PropName, True);

    // Update the corresponding component if mapped
    UpdateComponent(PropName, Value);
  finally
    // No need to free TRttiContext as it's a record
  end;
end;

procedure TQryRecInfo.SetInfoCurrency(Index: Integer; const Value: Currency);
begin
  SetInfo(Index, TValue.From<Currency>(Value));
end;

procedure TQryRecInfo.SetInfoString(Index: Integer; const Value: string);
begin
  SetInfo(Index, TValue.From<string>(Value));
end;

procedure TQryRecInfo.SetInfoInteger(Index: Integer; const Value: Integer);
begin
  SetInfo(Index, TValue.From<Integer>(Value));
end;

procedure TQryRecInfo.SetInfoInt64(Index: Integer; const Value: Int64);
begin
  SetInfo(Index, TValue.From<Int64>(Value));
end;

procedure TQryRecInfo.SetInfoExtended(Index: Integer; const Value: Extended);
begin
  SetInfo(Index, TValue.From<Extended>(Value));
end;

procedure TQryRecInfo.SetInfoDateTime(Index: Integer; const Value: TDateTime);
begin
  SetInfo(Index, TValue.From<TDateTime>(Value));
end;

procedure TQryRecInfo.SetInfoBoolean(Index: Integer; const Value: Boolean);
begin
  SetInfo(Index, TValue.From<Boolean>(Value));
end;

procedure TQryRecInfo.SetInfoVariant(Index: Integer; const Value: Variant);
begin
  SetInfo(Index, TValue.From<Variant>(Value));
end;

procedure TQryRecInfo.SetInfoNullableBoolean(Index: Integer; const Value: TNullable<Boolean>);
begin
  SetInfo(Index, TValue.From<TNullable<Boolean>>(Value));
end;

procedure TQryRecInfo.SetInfoNullableCurrency(Index: Integer; const Value: TNullable<Currency>);
begin
  SetInfo(Index, TValue.From<TNullable<Currency>>(Value));
end;

procedure TQryRecInfo.SetInfoNullableDateTime(Index: Integer; const Value: TNullable<TDateTime>);
begin
  SetInfo(Index, TValue.From<TNullable<TDateTime>>(Value));
end;

procedure TQryRecInfo.SetInfoNullableExtended(Index: Integer; const Value: TNullable<Extended>);
begin
  SetInfo(Index, TValue.From<TNullable<Extended>>(Value));
end;

procedure TQryRecInfo.SetInfoNullableInteger(Index: Integer; const Value: TNullable<Integer>);
begin
  SetInfo(Index, TValue.From<TNullable<Integer>>(Value));
end;

procedure TQryRecInfo.SetInfoNullableInt64(Index: Integer; const Value: TNullable<Int64>);
begin
  SetInfo(Index, TValue.From<TNullable<Int64>>(Value));
end;

procedure TQryRecInfo.SetInfoNullableString(Index: Integer; const Value: TNullable<string>);
begin
  SetInfo(Index, TValue.From<TNullable<string>>(Value));
end;

procedure TQryRecInfo.SetInfoNullableVariant(Index: Integer; const Value: TNullable<Variant>);
begin
  SetInfo(Index, TValue.From<TNullable<Variant>>(Value));
end;

procedure TQryRecInfo.MapToComponent(const PropName: string; Component: TComponent);
begin
  FComponents.AddOrSetValue(PropName, Component);
end;

{ TQryRecArray<T> }

constructor TQryRecArray<T>.Create;
begin
  inherited Create;
  FQryRecInfoList := TObjectList<T>.Create(True); // Owns objects
  FColumnMapping := TDictionary<string, Integer>.Create;
end;

destructor TQryRecArray<T>.Destroy;
begin
  FQryRecInfoList.Free;
  FColumnMapping.Free;
  inherited;
end;

procedure TQryRecArray<T>.ClearFilter;
begin
  FFilterSQL := '';
end;

function TQryRecArray<T>.GetCount: Integer;
begin
  Result := FQryRecInfoList.Count;
end;

function TQryRecArray<T>.Rec(Index: Integer): T;
begin
  if (Index < 0) or (Index >= FQryRecInfoList.Count) then
    raise EORMUtilsException.CreateFmt('Index %d out of bounds.', [Index]);

  Result := FQryRecInfoList[Index];
end;

procedure TQryRecArray<T>.MapToGrid(AGrid: TAdvStringGrid; const PropName: string; const ColumnName: string);
var
  ColIndex: Integer;
begin
  if not Assigned(AGrid) then
    Exit;

  ColIndex := AGrid.ColCount; // Default to an out-of-range value

  // Locate the column based on the column header name
  for ColIndex := 0 to AGrid.ColCount - 1 do
  begin
    if SameText(AGrid.Cells[ColIndex, 0], ColumnName) then
    begin
      FGrid := AGrid;
      FGrid.OnGetEditText := procedure (Sender: TObject; ACol, ARow: Integer; var Value: string)
        begin
          if (ARow > 0) and (ACol > 0) then
          begin
            GridToRecInfo(ACol, ARow);
          end;
        end;

      FGrid.OnSetEditText := procedure (Sender: TObject; ACol, ARow: Integer; const Value: string)
        begin
          if (ARow > 0) and (ACol > 0) then
          begin
            FGrid.Cells[ACol, ARow] := Value;
          end;
        end;

      FColumnMapping.AddOrSetValue(PropName, ColIndex);
      UpdateGrid;
      Break;
    end;
  end;
end;

procedure TQryRecArray<T>.UpdateGrid;
var
  i: Integer;
  RecInstance: T;
  ColName: string;
  ColIndex: Integer;
  Ctx: TRttiContext;
  Prop: TRttiProperty;
begin
  if not Assigned(FGrid) then
    Exit;

  Ctx := TRttiContext.Create;

  FGrid.RowCount := FQryRecInfoList.Count + 1;
  FGrid.FixedRows := 1;

  for i := 0 to FQryRecInfoList.Count - 1 do
  begin
    RecInstance := FQryRecInfoList[i];

    for ColName in FColumnMapping.Keys do
    begin
      if FColumnMapping.TryGetValue(ColName, ColIndex) then
      begin
        Prop := Ctx.GetType(T).GetProperty(ColName);
        if Assigned(Prop) then
        begin
          FGrid.Cells[ColIndex, i + 1] := Prop.GetValue(Pointer(RecInstance)).ToString;
        end;
      end;
    end;
  end;
end;

procedure TQryRecArray<T>.GridToRecInfo(ACol, ARow: Integer);
var
  ColName: string;
  PropName: string;
  Ctx: TRttiContext;
  Prop: TRttiProperty;
  RecInstance: T;
begin
  if FGrid.RowCount <= ARow then
    Exit;

  RecInstance := Rec(ARow - 1);

  for ColName in FColumnMapping.Keys do
  begin
    if FColumnMapping.TryGetValue(ColName, ACol) then
    begin
      PropName := ColName;

      Prop := Ctx.GetType(T).GetProperty(PropName);
      if Assigned(Prop) and Prop.IsWritable then
      begin
        Prop.SetValue(Pointer(RecInstance), FGrid.Cells[ACol, ARow]);
      end;
    end;
  end;
end;

procedure TQryRecArray<T>.FetchAllInstance(DBConn: TUniConnection; const QryTxt: string);
var
  qr: TUniQuery;
  RecInstance: T;
  Ctx: TRttiContext;
  ObjType: TRttiType;
  Prop: TRttiProperty;
  Field: TField;
  ORMFieldName: string;
begin
  if not Assigned(DBConn) then
    raise EORMUtilsException.Create('Database connection (DBConn) is not assigned.');

  if Trim(QryTxt).IsEmpty then
    raise EORMUtilsException.Create('Query text (QryTxt) cannot be empty.');

  qr := TUniQuery.Create(nil);
  try
    qr.Connection := DBConn;
    qr.SpecificOptions.Values['FetchAll'] := 'True';
    qr.SpecificOptions.Values['CreateConnection'] := 'False';
    qr.SQL.Text := QryTxt;
    qr.Open;

    if qr.IsEmpty then
      Exit; // No records to fetch

    Ctx := TRttiContext.Create;
    ObjType := Ctx.GetType(T);

    try
      while not qr.Eof do
      begin
        RecInstance := T.Create;
        try
          // Iterate over each property of T and assign values from the query
          for Prop in ObjType.GetProperties do
          begin
            if not Prop.IsWritable then
              Continue;

            // Attempt to find the corresponding field in the query
            Field := qr.FindField(Prop.Name);
            if not Assigned(Field) then
              Continue; // Field not found, skip

            ORMFieldName := '_' + Prop.Name;

            // Handle TNullable<T> types
            if Prop.PropertyType.TypeKind = tkRecord then
            begin
              // Expecting TNullable<T>
              // Attempt to find the backing field for the nullable property
              if ObjType.GetField(ORMFieldName) = nil then
               Continue; // Backing field not found, skip

              if Prop.PropertyType.Name.StartsWith('TNullable<') then
              begin
                // Use RTTI to determine the generic type parameter
                if Field.IsNull then
                  ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), TValue.From<TNullable<Variant>>(NullValue))
                else
                begin
                  // Determine the generic type and set the value accordingly

                  if Prop.PropertyType.Name = 'TNullable<System.string>' then
                    ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), TValue.From<TNullable<string>>(Field.AsString))
                  else if Prop.PropertyType.Name = 'TNullable<System.Integer>' then
                    ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), TValue.From<TNullable<Integer>>(Field.AsInteger))
                  else if Prop.PropertyType.Name = 'TNullable<System.Int64>' then
                    ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), TValue.From<TNullable<Int64>>(Field.AsLargeInt))
                  else if Prop.PropertyType.Name = 'TNullable<System.Extended>' then
                    ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), TValue.From<TNullable<Extended>>(Field.AsFloat))
                  else if Prop.PropertyType.Name = 'TNullable<System.Currency>' then
                    ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), TValue.From<TNullable<Currency>>(Field.AsCurrency))
                  else if Prop.PropertyType.Name = 'TNullable<System.TDateTime>' then
                    ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), TValue.From<TNullable<TDateTime>>(Field.AsDateTime))
                  else if Prop.PropertyType.Name = 'TNullable<System.Boolean>' then
                    ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), TValue.From<TNullable<Boolean>>(Field.AsBoolean))
                  else if Prop.PropertyType.Name = 'TNullable<System.Variant>' then
                    ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), TValue.From<TNullable<Variant>>(Field.Value))
                  else
                    raise EORMUtilsException.CreateFmt('Unsupported TNullable type: %s', [Prop.PropertyType.Name]);
                end;
              end
              else
                raise EORMUtilsException.CreateFmt('Unsupported record type: %s', [Prop.PropertyType.Name]);
            end
            else
            begin
              // Handle non-nullable types
              case Prop.PropertyType.TypeKind of
                tkString, tkLString, tkWString, tkUString:
                  ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), Field.AsString);
                tkInteger:
                  ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), Field.AsInteger);
                tkInt64:
                  ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), Field.AsLargeInt);
                tkFloat:
                  if Prop.PropertyType.Handle = TypeInfo(Currency) then
                    ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), Field.AsCurrency)
                  else if Prop.PropertyType.Handle = TypeInfo(TDateTime) then
                    ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), Field.AsDateTime)
                  else
                    ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), Field.AsFloat);
                tkVariant:
                  ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), TValue.FromVariant(Field.AsVariant));
                tkEnumeration:
                  if Prop.PropertyType.Handle = TypeInfo(Boolean) then
                    ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), Field.AsBoolean)
                  else
                    ObjType.GetField(ORMFieldName).SetValue(Pointer(RecInstance), Field.AsString);
              else
                // Unsupported type; you can extend this as needed
                Continue;
              end;
            end;
          end;

          // Add the populated record to the list
          FQryRecInfoList.Add(RecInstance);
        except
          RecInstance.Free;
          raise; // Re-raise the exception after cleanup
        end;
        qr.Next;
      end;
      UpdateGrid;
    finally
      // No need to free TRttiContext as it's a record
    end;
  finally
    qr.Free;
  end;
end;

function TQryRecArray<T>.GetEnumerator: TEnumerator<T>;
begin
  Result := FQryRecInfoList.GetEnumerator;
end;

class function TQryRecArray<T>.FetchAll(DBConn: TUniConnection; const QryTxt: string): TQryRecArray<T>;
var
  Instance: TQryRecArray<T>;
begin
  Instance := TQryRecArray<T>.Create;
  try
    Instance.FetchAllInstance(DBConn, QryTxt);
    Result := Instance;
  except
    Instance.Free;
    raise;
  end;
end;

end.

-----------------

Perform the changes to orm_utils unit.