删除支持表将删除物化视图。

Question

当删除物化视图的支持表时，物化视图也会被删除吗？我理解在没有支持表的情况下，物化视图是无效的，但是删除物化视图似乎有点不寻常。

物化视图如下所示

create materialized view if not exists ea_master.geography_hierarchy
as
Select 
 parent.geography_id  as parent_geography_id
 ,child.geography_id  as child_geography_id
from ea_master.Geography parent
join ea_master.Polygon pParent on pParent.polygon_id = parent.polygon_id 
join ea_master.Polygon pChild on ST_Contains(pParent.geometry, pChild.geometry)
join ea_master.Geography child on child.polygon_id  = pChild.polygon_id 
with no data;

用于删除备份表的查询：DROP TABLE ea_master.geography CASCADE;

请注意，在发出删除备份表的命令之前，物化视图将使用数据刷新。

Answer 1

感谢postgres-松弛通道上的@Raptélan，他为我提供了带有delete table参数的cascade文档。根据文档，预期文档摘录的行为如下：

DROP TABLE always removes any indexes, rules, triggers, and constraints that exist 
for the target table. However, to drop a table that is referenced by a view or a 
foreign-key constraint of another table, CASCADE must be specified. (CASCADE will 
remove a dependent view entirely, but in the foreign-key case it will only remove 
the foreign-key constraint, not the other table entirely.)

不幸的是，似乎需要级联参数来删除支持表，以确保视图与其一起被删除。每次使用级联选项删除备份表时，我都必须重新创建视图。

此外，我还将这个级联参数与外键合并为on delete cascade参数。