数据库发现
          
        
定义
CREATE DB_DISCOVERY RULE databaseDiscoveryRuleDefinition [, databaseDiscoveryRuleDefinition] ...
ALTER DB_DISCOVERY RULE databaseDiscoveryRuleDefinition [, databaseDiscoveryRuleDefinition] ...
DROP DB_DISCOVERY RULE ruleName [, ruleName] ...
databaseDiscoveryRuleDefinition:
    ruleName(resources, discoveryTypeDefinition)
resources:
    RESOURCES(resourceName [, resourceName] ...)
discoveryTypeDefinition:
    TYPE(NAME=discoveryType [, PROPERTIES([algorithmProperties] )] )
algorithmProperties:
    algorithmProperty [, algorithmProperty] ...
algorithmProperty:
    key=value                          
discoveryType 指定数据库发现服务类型,ShardingSphere 内置支持 MGR 
- 重复的 
ruleName 将无法被创建 
示例
CREATE DB_DISCOVERY RULE ha_group_0 (
RESOURCES(resource_0,resource_1),
TYPE(NAME=mgr,PROPERTIES(groupName='92504d5b-6dec',keepAliveCron=''))
);
ALTER DB_DISCOVERY RULE ha_group_0 (
RESOURCES(resource_0,resource_1,resource_2),
TYPE(NAME=mgr,PROPERTIES(groupName='92504d5b-6dec' ,keepAliveCron=''))
);
DROP DB_DISCOVERY RULE ha_group_0;