analyticsprod=# DROP TABLE IF EXISTS facts.auto_events_bk_20170223;

ERROR: cannot drop table auto_events_bk_20170223 because other objects depend on it

HINT: Use DROP ... CASCADE to drop the dependent objects too.

通過\d+ auto_events_bk_20170223 查看表結構，發現並沒有其他表的外鍵約束，所以排除；

然後通過\dv+命令在schema：facts下查看視圖，但是發現沒有任何view存在，但是view可能存在其他schema或db,

那麽問題來了,如何在整個數據庫中找到與這個表有依賴的的view?

這裏AWS Redshift已經給我們提供了一個好的方法,參考鏈接：https://docs.aws.amazon.com/redshift/latest/dg/r_DROP_TABLE.html

創建一個視圖find_depend:

create view find_depend as
select distinct c_p.oid as tbloid,
n_p.nspname as schemaname, c_p.relname as name,
n_c.nspname as refbyschemaname, c_c.relname as refbyname,
c_c.oid as viewoid
from pg_catalog.pg_class c_p
join pg_catalog.pg_depend d_p
on c_p.relfilenode = d_p.refobjid
join pg_catalog.pg_depend d_c
on d_p.objid = d_c.objid
join pg_catalog.pg_class c_c
on d_c.refobjid = c_c.relfilenode
left outer join pg_namespace n_p
on c_p.relnamespace = n_p.oid
left outer join pg_namespace n_c
on c_c.relnamespace = n_c.oid
where d_c.deptype = 'i'::"char"
and c_c.relkind = 'v'::"char";

查詢視圖找到與表auto_events_bk_20170223相關的view:

analyticsprod=# select * from facts.find_depend where schemaname='facts' and name not in ('find_depend') order by name;
 tbloid | schemaname |          name           | refbyschemaname |  refbyname  | viewoid
--------+------------+-------------------------+-----------------+-------------+---------
 879566 | facts      | auto_events_bk_20170223 | public          | map_routes2 |  965969
 879566 | facts      | auto_events_bk_20170223 | public          | map_routes  |  966155
 879566 | facts      | auto_events_bk_20170223 | public          | map_edges   | 1019697
(3 rows)

analyticsprod=# set search_path to public;

analyticsprod=# \dv
               List of relations
 schema |         name          | type | owner
--------+-----------------------+------+-------
 public | map_edges             | view | fengw
 public | map_edges_group       | view | fengw
 public | map_route_edges_group | view | fengw
 public | map_routes            | view | fengw
 public | map_routes2           | view | fengw
 public | map_routes_group      | view | fengw
(6 rows)

最後如果判斷這些相關的view沒有用的話，可以通過命令drop table auto_events_bk_20170223 cascade刪除表，包括視圖一同刪除。

Redshift drop有依賴關系的表