🚀 go-pugleaf

Clayton Arends wrote:
> All,
>
> I'm trying to convert the numerical data type returned by OpenSchema
> to the native enumerated TFieldType.  VarTypeToDataType() works for
> many of the simpler data types (such as integer and boolean) but not
> for string and ADO types.  Please reference the following code:
>
>   Variant tvars[4] = { Unassigned(), Unassigned(), tableName,
> Unassigned() };
>
>   TADODataSet*  dataSet = new TADODataSet(NULL);
>   std::auto_ptr<TADODataSet> auto_dataSet(dataSet);
>
>   ServerData.Connection->OpenSchema(
>       siColumns, VarArrayOf(tvars, 3), EmptyParam, dataSet);
>   String  msg = "Field count: " + String(dataSet->FieldCount) + "\n";
>
>   TField* field;
>   while (!dataSet->Eof)
>   {
>     field = dataSet->Fields->FieldByName("COLUMN_NAME");
>     msg += field->AsString + " => ";
>
>     field = dataSet->Fields->FieldByName("DATA_TYPE");
>     TFieldType  fieldType = VarTypeToDataType(field->AsInteger);

field -> AsInteger is actually a C++ unsigned short in this case
(DBTYPE_UI2) and is an OLEDB Type Indicator. Not all the OLEDB Type
Indicators match the Variant types. See the Type Indicators topic in the
OLEDB Programmer's Reference in MSDN.

I don't know how to go from the OLEDB Type Indicators to an actual BCB VCL
data type, so I just test out the value of DATA_TYPE against the OLEDB types
listed in the aforementioned topic. The topic gives a pretty good
explanation of the OLEDB datatypes. If you don't have MSDN library, MS has
it on their web site for anybody to use.