TSQlite3Dataset Blobs
lazarus / 16-Databases

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davesimplewear · 2010-10-21 03:30

Hi can anyone tell me if TSQlite3Dataset supports blobs, I see you can
specify Blob fields but does the dataset support them ?

Regards
Dave

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xenblaise · 2010-10-21 04:29

uses db.....
// TBlobField uses db
function addwithBlob(yourBlobData:?): Integer;
var
  rs: TSQLQuery;
  tptStream: TMemoryStream;
  id: Integer;
begin

  rs := TSQLQuery.Create(nil);
  rs.DataBase := mycon;

  rs.sql.Text := 'SELECT * FROM yourtable';
  rs.Open;
  rs.Append;

  tptStream := TMemoryStream.Create();
  tptStream.write( yourBlobData, yourBlobData.size);

  //HERES the blob field
  (rs.FieldByName('yourblobfield') as
TBlobField).LoadFromStream(tptStream);


  rs.post();
  rs.ApplyUpdates;

  id := rs.FieldByName('ID').AsInteger;
  tptStream.Free();
  rs.Close();
  rs.Free();
  addwithBlob := id;
end;

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davesimplewear · 2010-10-21 05:31

Thanks for your reply, I see your code was for TSQLQuery not
TSqlite3Dataset, does this also work for the TSqlite3Dataset.

Regards
Dave

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xenblaise · 2010-10-21 09:38

Quotedoes this also work for the TSqlite3Dataset.

Yes; (try it, I haven't tried)
Just replace
rs: TSQLQuery;
TO
rs: TSQLite3dataset;


But why use TSqlite3Dataset which is specific only for SQLite.

Use TSQLQuery, for anytime you will change your connection database
from sqlite to firebird to anySQL
No problem using it.  You dont have to change anycode for dataset
properties.

TSQLQuery is a global dataset for any connection, its a decendant of
TDataSet.

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xenblaise · 2010-10-23 09:49

dave?
how is it?

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davesimplewear · 2010-10-23 19:43

Sorry, haven't had time to try yet, will let you know when I have,
thanks for the pointer.

Regards
Dave

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xenblaise · 2010-11-05 06:15

The TSqlite3Dataset that comes with fpc/lazarus does not support yet
blob fields. Sqlite itself supports blob fields, just is not
implemented in that component.

from Luiz, but Im not sure about this mean(but my code does the task).

Can you confirm it, since your the one who's really testing it.

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davesimplewear · 2010-11-05 09:33

No, it does not do what I wanted which was to save picture to the blob
field, it may do a text blob, SqlitePassDbo saves both, but I much
prefer using the Sqlite3dataset, maybe Luiz will get around to doing
the Blob support, I am sure he is fairly busy, so what I do currently
is save the filepath of the image to the database and work with that,
not very elegant I know.

Regards
dave

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LuizAmérico · 2010-11-05 14:04

Blob support is on my plans.

I did not implemented yet because it will be necessary do a radical
change in the internal way of storing data. This can lead for some
bugs so must be done with caution and lot of testing.