System.Data.OracleClient.OracleCommandBuilder，如何生成UpdateCommand

private IDbCommand BuildUpdateCommand(DataTableMapping mappings, DataRow dataRow)
{
      IDbCommand command1 = this.InitializeCommand(this.UpdateCommand);
      StringBuilder builder1 = this.GetStringBuilder();
      int num1 = 0;
      string text1 = " SET ";
      builder1.Append("UPDATE ");
      builder1.Append(this.QuotedBaseTableName);
      int num2 = this._dbSchemaRows.Length;
      for (int num3 = 0; num3 < num2; num3++)
{
            DBSchemaRow row1 = this._dbSchemaRows[num3];
            if (((row1 != null) && (row1.BaseColumnName.Length != 0)) && this.IncludeInUpdateSet(row1))
{
                  object obj1 = null;
                  string text2 = this._sourceColumnNames[num3];
                  if ((mappings != null) && (dataRow != null))
{
                        DataColumn column1 = this.GetDataColumn(text2, mappings, dataRow);
                        if ((column1 == null) || (row1.IsReadOnly && column1.ReadOnly))
{
                              goto Label_013D;
                        }
                        obj1 = this.GetColumnValue(dataRow, column1, DataRowVersion.Current);
                        if (this.IsNotBehavior(CommandBuilderBehavior.UpdateSetSameValue))
{
                              object obj2 = this.GetColumnValue(dataRow, column1, DataRowVersion.Original);
                              if ((obj2 == obj1) || ((obj2 != null) && obj2.Equals(obj1)))
{
                                    goto Label_013D;
                              }
                        }
                  }
                  builder1.Append(text1);
                  text1 = ", ";
                  builder1.Append(this.QuotedColumn(row1.BaseColumnName));
                  builder1.Append(" = ");
                  builder1.Append(this.CreateParameterForValue(command1, text2, DataRowVersion.Current, num1, obj1, row1));
                  num1++;
            }
      Label_013D:;
      }
      bool flag1 = 0 == num1;
      num1 = this.BuildWhereClause(mappings, dataRow, builder1, command1, num1, true);
      command1.CommandText = builder1.ToString();
      OracleCommandBuilder.RemoveExtraParameters(command1, num1);
      this.UpdateCommand = command1;
      if (!flag1)
{
            return command1;
      }
      return null;
}