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{*******************************************************}
{ }
{ 继承范例 }
{ }
{ }
{ 版权所有 (C) 2000,2001 真光软件 }
{*******************************************************}
unit clsPerson;
{*******************************************************
项目:
模块:TPerson,TTeacher,TStudent
描述:OOP范例类
版本:1.0
日期:2001.9.23
作者:黄洪烈
更新:2001.9.23
TODO:
*******************************************************}
interface
uses
clsApplication,Forms,classes,Dialogs;
const
C_tblStudent='student.db';//学生类表名
C_tblTeacher='teacher.db';//老师类表名
type
TPerson=class(TDbRecordset)
private
FTelephone: string;
FId: string;
FName: string;
function GetId: string;
function GetName: string;
function GetTelephone: string;
protected
procedure BindFieldValues;virtual;//设置字段值
public
property Id:string read GetId write FId;
property Name:string read GetName write FName;
property Telephone:string read GetTelephone write FTelephone;
procedure ShowId;//显示编码
end;
TStudent=class(TPerson)
private
FTotalScore: integer;
function GetTotalScore: integer;
protected
procedure BindFieldValues;override;//设置字段值
public
constructor Create(AOwner:TComponent);override;
function Post:boolean;override;
property TotalScore:integer read GetTotalScore write FTotalScore;
end;
TTeacher=class(TPerson)
private
FSubject: string;
function GetSubject: string;
protected
procedure BindFieldValues;override;//设置字段值
public
constructor Create(AOwner:TComponent);override;
function Post:boolean;override;
property Subject:string read GetSubject write FSubject;
end;
implementation
{ TPerson }
{设置字段值}
procedure TPerson.BindFieldValues;
begin
FTable.Edit;
FTable.FieldByName('Id').AsString:=FId;
FTable.FieldByName('Name').AsString:=FName;
FTable.FieldByName('Telephone').AsString:=FTelephone;
end;
{定义字段属性}
function TPerson.GetId: string;
begin
FId:=FTable.FieldByName('Id').AsString;
Result:=FId;
end;
function TPerson.GetName: string;
begin
FName:=FTable.FieldByName('Name').AsString;
Result:=FName;
end;
function TPerson.GetTelephone: string;
begin
FTelephone:=FTable.FieldByName('Telephone').AsString;
Result:=FTelephone;
end;
{显示编码}
procedure TPerson.ShowId;
var
IdCaption,Id:string;
begin
Id:=FTable.FieldByName('Id').AsString;
if FTable.TableName=C_tblStudent then
IdCaption:='Student Id:'
else if FTable.TableName=C_tblTeacher then
IdCaption:='Teacher Id:';
ShowMessage(IdCaption+Id);
end;
{ TStudent }
{设置字段值}
procedure TStudent.BindFieldValues;
begin
inherited;
FTable.FieldByName('TotalScore').AsInteger:=FTotalScore;
end;
constructor TStudent.Create(AOwner: TComponent);
begin
inherited;
FTable.TableName:=C_tblStudent;
FTable.Active:=True;
end;
{定义字段属性}
function TStudent.GetTotalScore: integer;
begin
FTotalScore:=FTable.FieldByName('TotalScore').AsInteger;
Result := FTotalScore;
end;
{保存记录}
function TStudent.Post: boolean;
begin
FTable.Insert;
BindFieldValues;
Result:=Inherited Post;
end;
{ TTeacher }
{设置字段值}
procedure TTeacher.BindFieldValues;
begin
inherited;
FTable.FieldByName('Subject').AsString:=FSubject;
end;
constructor TTeacher.Create(AOwner: TComponent);
begin
inherited;
FTable.TableName:=C_tblTeacher;
FTable.Active:=True;
end;
{定义字段属性}
function TTeacher.GetSubject: string;
begin
FSubject:=FTable.FieldByName('Subject').AsString;
Result := FSubject;
end;
{保存记录}
function TTeacher.Post: boolean;
begin
FTable.Insert;
BindFieldValues;
Result:=Inherited Post;
end;
end.
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