TDataViewSourceEDBUpdateAdd - Exemples

TDataViewSourceEDBUpdateAdd = class (TDataViewSourceExternalDB)

Interface de TDataViewSourceEDBUpdateAdd

Exemples de TDataViewSourceEDBUpdateAdd

Nous prendrons dans notre exemple le cas d'une base de données externe avec une table DATA défini comme suit :

Nom du champ	Type du champ
TheDate	Date
year	entier
month	entier
day	entier
hour	entier
minute	entier
seconde	entier

unit MyExternalDB;

interface

uses QubesDataViewsSources.ExternalDB, QubesDataViews;

type
TDataViewSourceExternalDBTime = class(TDataViewSourceEDBUpdateAdd)
public
constructor Create(driver: String; parameters: array of string);
function Restart(dataView: TDataView): string; override;
function Update(dataView: TDataView; checkpoint: string): string; override;
end;

implementation

uses SysUtils;

constructor TDataViewSourceExternalDBTime.Create(driver: String; parameters: array of string);
begin
inherited Create(driver, parameters);
FFieldsDef.Add('TheDate=TheDate');
FFieldsDef.Add('year=year');
FFieldsDef.Add('month=month');
FFieldsDef.Add('day=day');
FFieldsDef.Add('hour=hour');
FFieldsDef.Add('minute=minute');
FFieldsDef.Add('seconde=seconde');
FFieldsType.Add(ftFloat, ftInteger, ftInteger, ftInteger, ftInteger, ftInteger, ftInteger);
end;

function TDataViewSourceExternalDBTime.Restart(dataView: TDataView): string;
var
select : array of String;
begin
for var i:=0 to dataView.Fields.Count-1 do begin
select.Add(FFieldsDef.Values[dataView.FieldsSource[i]]);
end;

var q := 'select '+select.Join(',')+' from DATA order by '+dataView.PKFieldFormula;
var dataSet := FDataBase.Query(q);
Result := RestartDataView(dataView, dataSet);
end;

function TDataViewSourceExternalDBTime.Update(dataView: TDataView; checkpoint: string): string;
var
select : array of String;
begin
for var i:=0 to dataView.Fields.Count-1 do
select.Add(FFieldsDef.Values[dataView.FieldsSource[i]]);
var dataSet := FDataBase.Query('select '+select.Join(',')+' from DATA where '+dataView.PKFieldFormula+'>:checkpoint order by '+dataView.PKFieldFormula,[StrToFloat(checkpoint)]);
Result := UpdateDataView(dataView, dataSet);
if Result ='' then Result := checkpoint;
end;