>
>Subject: Re: [sqlite] Suppressing column (field) headers?
> From: [EMAIL PROTECTED]
> Date: Mon, 22 Nov 2004 10:23:37 +1000
> To: [EMAIL PROTECTED]
>[EMAIL PROTECTED]
>21/11/2004 04:56 PM
>Please respond to sqlite-users
>
>
> To: [EMAIL PROTECTED]
> cc:
> Subject: [sqlite] Suppressing column (field) headers?
>
>
>
>> 1. How can I get the dll to return JUST the desired data?
>> When I send the following SQL, for example,
>> select colEntry from tblEntry where colNum = 3
>> the textbox shows
>> colEntry
>> "The text in the column."
>> <newline>
>
>This is being done by your delphi wrapper.
I beat around doing traces until I began to get that picture. The
code is doing things with TStrings and TSringlists.
>Please consult its documentation.
I wish. Heh.
>The "C" interface of sqlite (for both 2.8 series and 3.0
>series) returns the column names and column values separately, and doesn't
>return any extra "quote" characters.
Makes sense.
>Clay Dowling wrote:
>> You can get just the data that you want by using the prepared statements
>> feature of the 3.0.x dll. It sounds like you're using the table output
>> method for getting your results. This is fine, but it means that you
>need
>> it ignore the first row of data, which in the table interface is the
>> column labels.
>
>This statement makes you sound like you're taking crazy pills, Clay
>(prepared statements and non-prepared statements aren't functionally
>different in sqlite)... but I'm interested to know if you have a grain of
>truth hidden in there. Are you familiar with the delphi wrapper Mswarm is
>using? Which delphi wrapper are you using, Mswarm?
It says: "Simple class interface for SQLite. Hacked in by Ben Hochstrasser
([EMAIL PROTECTED]) Thanks to Roger Reghin ([EMAIL PROTECTED]) for his
idea to ValueList."
>What does the code that issues your query look like?
Benjamin, so far as I can tell, the relevant code is as follows:
fTable: TStrings;
fLstName: TStringList;
fLstVal: TStringList;
SQLite_Exec: function(db: Pointer; SQLStatement: PChar; CallbackPtr: Pointer;
Sender: TObject; var ErrMsg: PChar): integer; cdecl;
function ExecCallback(Sender: TObject; Columns: Integer; ColumnValues: Pointer;
ColumnNames: Pointer): integer; cdecl;
var
PVal, PName: ^PChar;
n: integer;
sVal, sName: String;
begin
Result := 0;
with Sender as TSQLite do
begin
if (Assigned(fOnData) or Assigned(fTable)) then
begin
fLstName.Clear;
fLstVal.Clear;
if Columns > 0 then
begin
PName := ColumnNames;
PVal := ColumnValues;
for n := 0 to Columns - 1 do
begin
fLstName.Append(PName^);
fLstVal.Append(PVal^);
inc(PName);
inc(PVal);
end;
end;
sVal := fLstVal.CommaText;
sName := fLstName.CommaText;
if Assigned(fOnData) then
fOnData(Sender, Columns, sName, sVal);
if Assigned(fTable) then
begin
if fTable.Count = 0 then
fTable.Append(sName);
fTable.Append(sVal);
end;
end;
end;
end;
function TSQLite.Query(Sql: String; Table: TStrings = nil): boolean;
begin
fError := SQLITE_ERROR;
if fIsOpen then
begin
fPMsg := nil;
fBusy := True;
fTable := Table;
if fTable <> nil then
fTable.Clear;
fError := SQLite_Exec(fSQLite, PChar(Sql), @ExecCallback, Self, fPMsg);
SQLite_FreeMem(fPMsg);
fChangeCount := SQLite_Changes(fSQLite);
fTable := nil;
fBusy := False;
if Assigned(fOnQueryComplete) then
fOnQueryComplete(Self);
end;
fMsg := ErrorMessage(fError);
Result := (fError <> SQLITE_OK);
end;
I haven't used TStrings much, but I'm guessing that appending to
TStrings creates the newlines, and that the .commatext method creates
the commas in the TStringlists. I still can't figure out which code
would add the "double quote" marks around returned text, though, if the
DLL doesn't return a string that way. I've search the code for the "
mark and the #value, but nothing turns up.
Thanks
