Q&A - Question

How to save a bitmap in SQLite field

Question

Danv asked on June 27, 2022, keyword: Developer Kernel

Hi all,

I am able to read a bitmap from a field and display it in a TImage.
This using the sqlQueryGetBlob function.

Now I want it the other way around: save a bitmap in the field.
So I found the sqlTableSetBlob procedure but I can not figure out the use of it.

Anyway ever used this and can show me a few lines how it is done?

Thanks in advance, Danny.

Answers

Artur Redzko (TatukGIS) replied June 27, 2022

Hi,
here is a sample code:

procedure SaveBitmap;
var
  cfg : TStringList ;
  odb : TGIS_DbSqlite ;
  stm : TGIS_MemoryStream ;
  bmp : TGIS_Bitmap ;
begin
  odb := TGIS_DbSqlite.Create ;
    odb.InitializeProvider ;
    cfg := TStringList.Create ;
      cfg.Values[ 'Sqlite' ] := 'c:\tmp\test.db' ;
      // solve "a database is locked" issue
      cfg.Values['PRAGMA journal_mode'] := 'WAL';
      cfg.Text := cfg.Text + #13#10 + GetSQLDialect( 'SQLITE' ) ;
      odb.sqlInitialize( cfg, cfg ) ;
      odb.sqlConnect( '', cfg ) ;
    cfg.Free ;

    bmp := TGIS_Bitmap.Create ;
    bmp.LoadFromFile( 'c:\tmp\test.jpg') ;
    stm := TGIS_MemoryStream.Create ;
    bmp.SaveToStream(stm);
    bmp.Free ;

    odb.sqlTableOpenWrite(1, 'UPDATE test SET Foto =:Foto WHERE id=1');
    odb.sqlTableSetBlob(1, 'Foto', Unassigned, stm);
    odb.sqlTablePost(1);
    stm.Free ;
    odb.sqlDisconnect ;
  odb.Free ;
end;

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