A transactional workflow is composed of traditional flat transactions, and its execution has relaxed transactional atomicity. Due to different termination characteristics of transactions, only one workflow is allowed to execute non-compensatable transactions with current scheduling protocols. In this paper, two granularities of conflict based on transaction classes and transaction instances are defined, and a scheduling protocol by using both granularities of conflict detection is proposed. Besides generating serializable and recoverable schedules, this method provides a higher degree of concurrency in following two ways. On the one hand, the fine-grained locking mechanism based on transaction instances is used to reduce conflict possibility among concurrent workflows. On the other hand, the coarse-grained conflict mechanism based on transaction classes is used to predict future conflict among workflows, multiple workflows are therefore allowed to execute non-compensatable transactions if they will not conflict in predicated future execution.