db:mysqldb: add ifRecordExist() method

Add ifRecordExist() method to return if a record already exists in a
data table.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
regression: update strategy assistant

Update strategy assistant function to contain more informations
required to do assistance or simulation.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
strategy:turt1: update assistant to do simulation

Update assistant to do simulation.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>