let transaction; 

        try {

            transaction = await this.ctx.model.transaction();

            await this.ctx.model.Collect.create({id: 39, author: 'zyu111', count: 1}, {transaction})

            await this.ctx.model.Collect.create({id: 42, author: 'zyu8228', count: 1}, {transaction})

            await transaction.commit();

        } catch (err) {

            // console.log(err)

            console.log('回滚了。。。')

            await transaction.rollback();

        }