Is there any function that it could return me the datatype name of the field in string?

Are you refering to a column in a database, a field in a data file, or what?

Usually there is a way to get the information from a database, assuming you have sufficient permissions to allow you to do so.

As for the Data File, that sort of depends on the data file and the manner in which you are accessing it.  

Other than that, the general IT answer, as always, is going to be, "It depends."

When I open a query in an adoquery and I load the columns I want to display in memoedit all the fields name e its datatype:

something like this:

field = product  datatype = ftstring size = 30

the fieldname and size I was able to inform, but datatype not.

The only way I found is that:

  if Qexcel.FieldByName(AFieldName).DataType = ftDateTime Then str :=   'ftDateTime '
  if Qexcel.FieldByName(AFieldName).DataType = ftFloat   Then str := 'ftFloat'

I need to compare with exited datatypes

Hi,

I got it :))

this was what I would like

function TFListCotImporta.TipoField(campo: String): String;
const
  cmp : array[0..37] of string = ('ftUnknown', 'ftString', 'ftSmallint', 'ftInteger', 'ftWord', 'ftBoolean', 'ftFloat', 'ftCurrency', 'ftBCD', 'ftDate', 'ftTime', 'ftDateTime', 'ftBytes',
                           'ftVarBytes', 'ftAutoInc', 'ftBlob', 'ftMemo', 'ftGraphic', 'ftFmtMemo', 'ftParadoxOle', 'ftDBaseOle', 'ftTypedBinary', 'ftCursor', 'ftFixedChar', 'ftWideString',
                           'ftLargeint', 'ftADT', 'ftArray', 'ftReference', 'ftDataSet', 'ftOraBlob', 'ftOraClob', 'ftVariant', 'ftInterface', 'ftIDispatch', 'ftGuid', 'ftTimeStamp', 'ftFMTBcd');

var
  x : variant;
begin
  x := TFieldType(Adoquery.FieldByName(campo).DataType);
  showMessage(cmp[StrToInt(x)])
end;

I forgot to mention that this technique of course works with ALL enumerated types, even your own, and does not require that you manually maintain another table of string constants for each and everyone of those enums types where you would need to get their value to string equivalent

Delphi do it for you. Which is precisely why I said Delphi is wonderful :o).
Did I said how great Delphi's RTTI (Run-Time Type Information) system is ?

thanks