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[solved] MySQL WITH_WIDEMEMO
Posted: 16.06.2014, 08:27
by cacofony
Hi,
{$DEFINE WITH_WIDEMEMO} // Have WIDEMEMO, For Delphi we turn these off if not applicable
Could this perhaps be explained further?
I have found issues with large VARCHAR fields or TEXT fields. By commenting this out problems disappear.
Loading strings from streams appears to cause the issue.
Tristan
Re: MySQL WITH_WIDEMEMO
Posted: 16.06.2014, 09:40
by cacofony
Sorry ignore that, it still has access violations.
ZDbcCache.pas
function TZRowAccessor.GetRawByteString(Const ColumnIndex: Integer;
var IsNull: Boolean): RawByteString;
Code: Select all
stAsciiStream, stUnicodeStream, stBinaryStream:
begin
try
TempBlob := GetBlobObject(FBuffer, ColumnIndex);
if (TempBlob <> nil) and not TempBlob.IsEmpty then
Result := TempBlob.GetString;
except
on E: Exception do
begin
Result := Format('%s, Column Index: %d, Column Type %d',
[E.Message, ColumnIndex, Integer(FColumnTypes[ColumnIndex - 1])]);
end;
end;
end;
This will happen for TEXT, LARGETEXT, SMALLTEXT and CAST as CHAR[n] where n > 500?
I placed the exception trap, the solumn type will be stUnicodeStream
Re: MySQL WITH_WIDEMEMO
Posted: 16.06.2014, 14:13
by cacofony
This can be easily replicated in the zeoslib test tables. Add some rows of text in the b_text field in table blob_values. I added 62 rows containing the text from lgpl.txt
Add a ZConnection, ZQuery, Datasource and link a DBGrid
Code: Select all
ZQuery.SQL.Clear;
ZQuery.SQL.Add('SELECT * FROM blob_values');
ZQuery.Open;
Scroll through the records and an access violation will occur here
Code: Select all
function TZMySQLBaseDriver.GetFieldData(Row: PZMySQLRow;
Offset: Cardinal): PAnsiChar;
begin
Result := PMYSQL_ROW(ROW)[Offset];
end;
Re: MySQL WITH_WIDEMEMO
Posted: 21.06.2014, 16:28
by cacofony
My testing would show EgonHugeist has fixed the issue with commit 3158. Nice work.
https://sourceforge.net/p/zeoslib/tickets/77/
Re: MySQL WITH_WIDEMEMO
Posted: 24.06.2014, 14:15
by papelhigienico
@miab3 or @cacofony can you close this (Put [SOLVED] in the title of the first message)???
I don't have sufficient privileges to do this...
