transaction_isolation 
==========================================

transaction_isolation 用于设置事务的隔离级别。


| **属性**  |                                                                                                               **描述**                                                                                                               |
|---------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 参数类型    | varchar                                                                                                                                                                                                                            |
| 默认值     | READ-COMMITTED                                                                                                                                                                                                                     |
| 取值范围    | * READ-UNCOMMITTED   * READ-COMMITTED   * REPEATABLE-READ   * SERIALIZABLE    |
| 生效范围    | * GLOBAL   * SESSION                                                                                                                            |
| 是否参与序列化 | 是                                                                                                                                                                                                                                  |