以前、Team Japanのブログに
EmployeeクラスのインスタンスからInsert文を
生成するサンプルのポストがありましたが、ちょっと改良してTClientDataSetを
動的生成する例を書いてみた。(って使い道があるかちょっと疑問です。)
一応ソースは、こんな感じ
- unit Unit3;
-
- interface
-
- uses
- DBClient;
-
- type DataSetOperator = Record
- function CreateDataSet(obj : TObject) : TClientDataSet;
- function AddRecord(cds : TClientDataSet; obj : TObject) : Boolean;
- End;
-
-
- implementation
-
- uses
- Rtti,TypInfo, DB, SysUtils;
-
-
- function DataSetOperator.AddRecord(cds: TClientDataSet; obj: TObject): Boolean;
- var
- ctx : TRttiContext;
- rtp : TRttiProperty;
- rtps : TArray<trttiproperty>;
- begin
-
- ctx := TRttiContext.Create;
-
- rtps := ctx.FindType(obj.UnitName + '.' + obj.ClassName).GetProperties;
- cds.Append;
- for rtp in rtps do
- begin
- cds.FieldByName(rtp.Name).Value := rtp.GetValue(obj).AsVariant;
- end;
- cds.UpdateRecord;
- end;
-
- function DataSetOperator.CreateDataSet(obj: TObject): TClientDataSet;
- var
- ctx : TRttiContext;
- rtp : TRttiProperty;
- rtps : TArray<trttiproperty>;
- cds : TClientDataSet;
- ft : TFieldType;
- fn : String;
- ftSize : Integer;
-
- begin
-
- cds := TClientDataSet.Create(nil);
-
- ctx := TRttiContext.Create;
-
- rtps := ctx.FindType(obj.UnitName + '.' + obj.ClassName).GetProperties;
-
- for rtp in rtps do
- begin
-
-
- ftSize := 0;
- if CompareText(rtp.PropertyType.Name,'Integer') = 0 then ft := ftInteger;
- if CompareText(rtp.PropertyType.Name,'String') = 0 then
- begin
- ft := ftString;
- ftSize := 50;
- end;
- if CompareText(rtp.PropertyType.Name,'TDateTime') = 0 then ft := ftDateTime;
- if CompareText(rtp.PropertyType.Name,'Currency') = 0 then ft := ftCurrency;
-
-
- cds.FieldDefs.Add(rtp.Name,ft,ftSize);
-
- end;
- cds.CreateDataSet;
- Result := cds;
-
-
- end;
-
- end.
-
- </trttiproperty></trttiproperty>
unit Unit3;
interface
uses
DBClient;
type DataSetOperator = Record
function CreateDataSet(obj : TObject) : TClientDataSet;
function AddRecord(cds : TClientDataSet; obj : TObject) : Boolean;
End;
implementation
uses
Rtti,TypInfo, DB, SysUtils;
{ DataSetFactory }
function DataSetOperator.AddRecord(cds: TClientDataSet; obj: TObject): Boolean;
var
ctx : TRttiContext;
rtp : TRttiProperty;
rtps : TArray;
begin
ctx := TRttiContext.Create;
rtps := ctx.FindType(obj.UnitName + '.' + obj.ClassName).GetProperties;
cds.Append;
for rtp in rtps do
begin
cds.FieldByName(rtp.Name).Value := rtp.GetValue(obj).AsVariant;
end;
cds.UpdateRecord;
end;
function DataSetOperator.CreateDataSet(obj: TObject): TClientDataSet;
var
ctx : TRttiContext;
rtp : TRttiProperty;
rtps : TArray;
cds : TClientDataSet;
ft : TFieldType;
fn : String;
ftSize : Integer;
//ftdf : TFieldDef;
begin
cds := TClientDataSet.Create(nil);
ctx := TRttiContext.Create;
rtps := ctx.FindType(obj.UnitName + '.' + obj.ClassName).GetProperties;
for rtp in rtps do
begin
//ここがちょっとダサイかも
//DelphiのRTTIの型とDBの型のマッチング
ftSize := 0;
if CompareText(rtp.PropertyType.Name,'Integer') = 0 then ft := ftInteger;
if CompareText(rtp.PropertyType.Name,'String') = 0 then
begin
ft := ftString;
ftSize := 50;
end;
if CompareText(rtp.PropertyType.Name,'TDateTime') = 0 then ft := ftDateTime;
if CompareText(rtp.PropertyType.Name,'Currency') = 0 then ft := ftCurrency;
//if CompareText(rtp.PropertyType.Name,'Currency') = 0 then ft := ftCurrency;
cds.FieldDefs.Add(rtp.Name,ft,ftSize);
end;
cds.CreateDataSet;
Result := cds;
//cds.FieldDefs.Add();
end;
end.
DBのデータ型の列挙とRTTIのデータ型の列挙が微妙に違っているので
そのマッピングを少々強引に行ってます。
で、上のユニットを利用する例が
- unit Unit1;
-
- interface
-
- uses
- Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
- Dialogs, StdCtrls, DB, Grids, DBGrids;
-
- type
- TForm1 = class(TForm)
- DBGrid1: TDBGrid;
- DataSource1: TDataSource;
- Button1: TButton;
- procedure Button1Click(Sender: TObject);
- private
-
- public
-
- end;
-
- var
- Form1: TForm1;
-
- implementation
-
- uses Unit2, Unit3,DBClient;
-
- {$R *.dfm}
-
- procedure TForm1.Button1Click(Sender: TObject);
- var
- Emp : TEmployee;
- DF : DataSetOperator;
- cds : TClientDataSet;
- begin
-
- Emp := TEmployee.Create;
-
- cds := DF.CreateDataSet(Emp);
- cds.Active := true;
- DataSource1.DataSet := cds;
-
-
- Emp.EmpNo := 2;
- Emp.FirstName := 'OldTPFun';
- Emp.LastName := 'Delphi';
- Emp.HireDate := StrToDate('2009/10/07');
- Emp.Salary := 100000.00;
- DF.AddRecord(cds,Emp);
-
- Emp.Free;
- end;
-
- end.
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, DB, Grids, DBGrids;
type
TForm1 = class(TForm)
DBGrid1: TDBGrid;
DataSource1: TDataSource;
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private 宣言 }
public
{ Public 宣言 }
end;
var
Form1: TForm1;
implementation
uses Unit2, Unit3,DBClient;
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
var
Emp : TEmployee;
DF : DataSetOperator;
cds : TClientDataSet;
begin
Emp := TEmployee.Create;
cds := DF.CreateDataSet(Emp);
cds.Active := true;
DataSource1.DataSet := cds;
//DataSource1.DataSet.Active := true;
Emp.EmpNo := 2;
Emp.FirstName := 'OldTPFun';
Emp.LastName := 'Delphi';
Emp.HireDate := StrToDate('2009/10/07');
Emp.Salary := 100000.00;
DF.AddRecord(cds,Emp);
Emp.Free;
end;
end.
このプログラム上で使っているEmployee型の定義は以下のとおりです。
- unit Unit2;
-
- interface
-
- type TEmployee = class
- private
- FEmpNo: Integer;
- FFirstName: String;
- FLastName: String;
- FHireDate: TDateTime;
- FSalary: Currency;
- procedure SetEmpNo(const Value: Integer);
- procedure SetFirstName(const Value: String);
- procedure SetLastName(const Value: String);
- procedure SetHireDate(const Value: TDateTime);
- procedure SetSalary(const Value: Currency);
- public
- property EmpNo : Integer read FEmpNo write SetEmpNo;
- property FirstName : String read FFirstName write SetFirstName;
- property LastName : String read FLastName write SetLastName;
- property HireDate : TDateTime read FHireDate write SetHireDate;
- property Salary : Currency read FSalary write SetSalary;
- end;
- implementation
-
-
-
- procedure TEmployee.SetEmpNo(const Value: Integer);
- begin
- FEmpNo := Value;
- end;
-
- procedure TEmployee.SetFirstName(const Value: String);
- begin
- FFirstName := Value;
- end;
-
- procedure TEmployee.SetHireDate(const Value: TDateTime);
- begin
- FHireDate := Value;
- end;
-
- procedure TEmployee.SetLastName(const Value: String);
- begin
- FLastName := Value;
- end;
-
- procedure TEmployee.SetSalary(const Value: Currency);
- begin
- FSalary := Value;
- end;
-
- end.
unit Unit2;
interface
type TEmployee = class
private
FEmpNo: Integer;
FFirstName: String;
FLastName: String;
FHireDate: TDateTime;
FSalary: Currency;
procedure SetEmpNo(const Value: Integer);
procedure SetFirstName(const Value: String);
procedure SetLastName(const Value: String);
procedure SetHireDate(const Value: TDateTime);
procedure SetSalary(const Value: Currency);
public
property EmpNo : Integer read FEmpNo write SetEmpNo;
property FirstName : String read FFirstName write SetFirstName;
property LastName : String read FLastName write SetLastName;
property HireDate : TDateTime read FHireDate write SetHireDate;
property Salary : Currency read FSalary write SetSalary;
end;
implementation
{ TEmployee }
procedure TEmployee.SetEmpNo(const Value: Integer);
begin
FEmpNo := Value;
end;
procedure TEmployee.SetFirstName(const Value: String);
begin
FFirstName := Value;
end;
procedure TEmployee.SetHireDate(const Value: TDateTime);
begin
FHireDate := Value;
end;
procedure TEmployee.SetLastName(const Value: String);
begin
FLastName := Value;
end;
procedure TEmployee.SetSalary(const Value: Currency);
begin
FSalary := Value;
end;
end.