public static Version GetVersionFromDatabase(DbConnectionStringBuilder builder)
{
using (var con = DatabaseCommandHelper.GetConnection(builder))
{
con.Open();
var cmd = DatabaseCommandHelper.GetCommand(@"SELECT top 1 version from RoundhousE.Version order by version desc", con);
var o = cmd.ExecuteScalar();
if (o == DBNull.Value)
{
return(new Version(0, 0, 0, 0));
}
return(new Version(o.ToString()));
}
}
public DataTable TryGetPreview()
{
DataTable chunk = new DataTable();
using (var con = DatabaseCommandHelper.GetConnection(_builder))
{
con.Open();
var da = DatabaseCommandHelper.GetDataAdapter(DatabaseCommandHelper.GetCommand(_sql, con));
int read = da.Fill(0, 100, chunk);
if (read == 0)
{
return(null);
}
return(chunk);
}
}
public DataTable GetChunk(IDataLoadEventListener job, GracefulCancellationToken cancellationToken)
{
if (_reader == null)
{
_con = DatabaseCommandHelper.GetConnection(_builder);
_con.Open();
job.OnNotify(this, new NotifyEventArgs(ProgressEventType.Information, "Running SQL:" + Environment.NewLine + Sql));
cmd = DatabaseCommandHelper.GetCommand(Sql, _con);
cmd.CommandTimeout = _timeout;
CommandAdjuster?.Invoke(cmd);
_reader = cmd.ExecuteReaderAsync(cancellationToken.AbortToken).Result;
_numberOfColumns = _reader.FieldCount;
}
int readThisBatch = 0;
timer.Start();
try
{
DataTable chunk = GetChunkSchema(_reader);
while (_reader.Read())
{
AddRowToDataTable(chunk, _reader);
readThisBatch++;
//we reached batch limit
if (readThisBatch == BatchSize)
{
return(chunk);
}
}
//if data was read
if (readThisBatch > 0)
{
return(chunk);
}
//data is exhausted
//if data was exhausted on first read and we are allowing empty result sets
if (firstChunk && AllowEmptyResultSets)
{
return(chunk);//return the empty chunk
}
//data exhausted
return(null);
}
catch (Exception e)
{
job.OnNotify(this, new NotifyEventArgs(ProgressEventType.Error, "Source read failed", e));
throw;
}
finally
{
firstChunk = false;
timer.Stop();
job.OnProgress(this, new ProgressEventArgs(_taskBeingPerformed, new ProgressMeasurement(TotalRowsRead, ProgressType.Records), timer.Elapsed));
}
}