/// <summary>
/// Atualiza as alterações nas tabelas no banco de dados.
/// </summary>
/// <param name="tables">As tabelas que devem ser atualizadas</param>
/// <returns>O número de linhas modificadas</returns>
protected int CommitChanges(params DataTable[] tables)
{
  try 
  {
    int modCount = 0;
    using (AdpConnection conn = CreateConnection())
      foreach (DataTable dt in tables) 
      {
        if (dt != null && dt.Rows.Count > 0) 
        {
          string originalTableName = dt.TableName;
          dt.TableName = GetPhysicalTableName(originalTableName);
          using (AdpDataAdapter da = new AdpDataAdapter())
          {
            DataTable add = dt.GetChanges(DataRowState.Added);
            DataTable del = dt.GetChanges(DataRowState.Deleted);
            DataTable upd = dt.GetChanges(DataRowState.Modified);

            if (add != null || del != null || upd != null)
              if (!BuildCommands(da, conn, dt))
                new AdpCommandBuilder(da, conn, dt);

            if (del != null) 
            {
              modCount += da.Update(del);
              ds.Merge(del);
            }
            
            if (upd != null) 
            {
              modCount += da.Update(upd);
              ds.Merge(upd);
            }
            
            if (add != null)
            {
              AdpCommand autoIncrementCmd = null;
              if (conn.Provider is MsSqlProvider) 
              {
                autoIncrementCmd = conn.CreateCommand();
                autoIncrementCmd.CommandText = "SELECT @@IDENTITY";
              }
              else
                Debug.WriteLine("Provider not supported: " + conn.Provider);

              if (autoIncrementCmd == null)
                modCount += da.Update(add);
              else
              {
                autoIncrementCmd.Prepare();

                foreach (DataRow row in add.Rows)
                {
                  da.Update(row);
                  if (add.PrimaryKey.Length == 1 && add.PrimaryKey[0].AutoIncrement)
                  {
                    DataColumn pk = add.PrimaryKey[0];

                    object id;
                    id = autoIncrementCmd.ExecuteScalar();
                  
                    if (!(id is DBNull))
                    {
                      bool oldRO = pk.ReadOnly;
                      pk.ReadOnly = false;
                      row[pk] = id;
                      pk.ReadOnly = oldRO;
                    }
                  }

                  modCount++;
                }
              }
              ds.Merge(add);
            }
          }
          dt.TableName = originalTableName;
        }
      }
    return modCount;
  }
  catch (Exception ex)
  {
    if (ex.Message.StartsWith("DELETE statement conflicted with COLUMN REFERENCE constraint"))
      throw new ConnectorException(ConnectorException.Types.ForeignKeyViolation, ex);
    else
      throw new ConnectorException(ex);
  }
}