title: Insert/update TBlobfield (aka image) using sql parameters
body: <p>I want to store images in a database using sql but cant seem to get it to work:</p>
  
  <pre><code>qry.SQL.Clear;
  qry.Sql.Add('update tbl set pic = :blobVal where id = :idVal');   
  qry.Parameters.ParamByName('idVal')._?:=1;
  </code></pre>
  
  <p>.Parameters has no .asinteger like .Param has but .Param isn't compatible with a TADOquery - to workaround I tried:</p>
  
  <pre><code>a_TParameter:=qry.Parameters.CreateParameter('blobval',ftBlob,pdinput,SizeOf(TBlobField),Null);
  a_TParam.Assign(a_TParameter);
  a_TParam.asblob:=a_Tblob;
  qry.ExecSql; 
  </code></pre>
  
  <p>This also doesnt work:</p>
  
  <pre><code>qry.SQL.Clear;
  qry.Sql.Add('update tbl set pic = :blobVal where id = 1')
  qry.Parameters.ParamByName('blobVal').LoadFromStream(img as a_TFileStream,ftGraphic);//ftblob 
  //or 
  qry.Parameters.ParamByName('blobVal').LoadFromFile('c:\sample.jpg',ftgrafic);//ftblob
  qry.ExecSql;
  </code></pre>