Title: Create a XML-file with data from some dataset
Question: How to generate the XML-file from linked dataset?
Answer:
Sometimes in our development we must export a data from dataset into different formats like MS Excel, Word, HTML, Text etc. Now in the Internet we have a new popular format - XML-file. So for large part of applications we wants to include the possibility of export into XML, of course.
I want to demonstrate the sample of one procedure for exporting of dataset's data into XML:
procedure DatasetToXML(Dataset: TDataset; FileName: string);
The first Dataset parameter is source dataset with data (yout Table or Query component, or someelse third-party dataset).
The second FileName parameter is a name of target XML-file.
{ SMExport suite's free demo
Data export from dataset into XML-file
Copyright(C) 2000, written by Shkolnik Mike
E-Mail: mshkolnik@rs-ukraine.kiev.ua
mshkolnik@yahoo.com
WEB: http://www.scalabium.com
http://www.geocities.com/mshkolnik
}
unit DS2XML;
interface
uses
Classes, DB;
procedure DatasetToXML(Dataset: TDataset; FileName: string);
implementation
uses
SysUtils;
var
SourceBuffer: PChar;
procedure WriteString(Stream: TFileStream; s: string);
begin
StrPCopy(SourceBuffer, s);
Stream.Write(SourceBuffer[0], StrLen(SourceBuffer));
end;
procedure WriteFileBegin(Stream: TFileStream; Dataset: TDataset);
function XMLFieldType(fld: TField): string;
begin
case fld.DataType of
ftString: Result := '"string" WIDTH="' + IntToStr(fld.Size) + '"';
ftSmallint: Result := '"i4"'; //??
ftInteger: Result := '"i4"';
ftWord: Result := '"i4"'; //??
ftBoolean: Result := '"boolean"';
ftAutoInc: Result := '"i4" SUBTYPE="Autoinc"';
ftFloat: Result := '"r8"';
ftCurrency: Result := '"r8" SUBTYPE="Money"';
ftBCD: Result := '"r8"'; //??
ftDate: Result := '"date"';
ftTime: Result := '"time"'; //??
ftDateTime: Result := '"datetime"';
else
end;
if fld.Required then
Result := Result + ' required="true"';
if fld.Readonly then
Result := Result + ' readonly="true"';
end;
var
i: Integer;
begin
WriteString(Stream, '
' +
'');
WriteString(Stream, '');
{write th metadata}
with Dataset do
for i := 0 to FieldCount-1 do
begin
WriteString(Stream, ' Fields[i].FieldName +
'" fieldtype=' +
XMLFieldType(Fields[i]) +
'/');
end;
WriteString(Stream, '');
WriteString(Stream, '');
WriteString(Stream, '');
end;
procedure WriteFileEnd(Stream: TFileStream);
begin
WriteString(Stream, '');
end;
procedure WriteRowStart(Stream: TFileStream; IsAddedTitle: Boolean);
begin
if not IsAddedTitle then
WriteString(Stream, 'end;
procedure WriteRowEnd(Stream: TFileStream; IsAddedTitle: Boolean);
begin
if not IsAddedTitle then
WriteString(Stream, '/');
end;
procedure WriteData(Stream: TFileStream; fld: TField; AString: ShortString);
begin
if Assigned(fld) and (AString '') then
WriteString(Stream, ' ' + fld.FieldName + '="' + AString + '"');
end;
function GetFieldStr(Field: TField): string;
function GetDig(i, j: Word): string;
begin
Result := IntToStr(i);
while (Length(Result) Result := '0' + Result;
end;
var Hour, Min, Sec, MSec: Word;
begin
case Field.DataType of
ftBoolean: Result := UpperCase(Field.AsString);
ftDate: Result := FormatDateTime('yyyymmdd', Field.AsDateTime);
ftTime: Result := FormatDateTime('hhnnss', Field.AsDateTime);
ftDateTime: begin
Result := FormatDateTime('yyyymmdd', Field.AsDateTime);
DecodeTime(Field.AsDateTime, Hour, Min, Sec, MSec);
if (Hour 0) or (Min 0) or (Sec 0) or (MSec 0) then
Result := Result + 'T' + GetDig(Hour, 2) + ':' + GetDig(Min, 2) + ':' + GetDig(Sec, 2) + GetDig(MSec, 3);
end;
else
Result := Field.AsString;
end;
end;
procedure DatasetToXML(Dataset: TDataset; FileName: string);
var
Stream: TFileStream;
bkmark: TBookmark;
i: Integer;
begin
Stream := TFileStream.Create(FileName, fmCreate);
SourceBuffer := StrAlloc(1024);
WriteFileBegin(Stream, Dataset);
with DataSet do
begin
DisableControls;
bkmark := GetBookmark;
First;
{write a title row}
WriteRowStart(Stream, True);
for i := 0 to FieldCount-1 do
WriteData(Stream, nil, Fields[i].DisplayLabel);
{write the end of row}
WriteRowEnd(Stream, True);
while (not EOF) do
begin
WriteRowStart(Stream, False);
for i := 0 to FieldCount-1 do
WriteData(Stream, Fields[i], GetFieldStr(Fields[i]));
{write the end of row}
WriteRowEnd(Stream, False);
Next;
end;
GotoBookmark(bkmark);
EnableControls;
end;
WriteFileEnd(Stream);
Stream.Free;
StrDispose(SourceBuffer);
end;
end.
PS: I created this simple procedure from own TSMExportToXML component which have a lot of useful extensions in export process. This component is part of shareware SMExport suite for Delphi/C++Builder so I cutted a part of code and created a simple procedure for exporting into XML.