postgresql postgres 将视图列的数据类型从未知更改为文本
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postgres change data type of view column from unknown to text
提问by Angga Saputra
I just create a new view as follows
我只是创建一个新视图如下
CREATE OR REPLACE VIEW gettreelistvw AS
SELECT "CRM".groupid, 'pointrewarding'::text AS applicationid, "CM".menuid, "CM".menuname, "CM".levelstructure, "CM".moduleid, "CM".haschild, "CM".installed
FROM core_capabilitymap "CRM"
JOIN core_menus "CM" ON "CRM".menuid::text = "CM".menuid::text;
ALTER TABLE gettreelistvw
when i execute this error appear
当我执行此错误时出现
ERROR: cannot change data type of view column "applicationid" from unknown to text
错误：无法将视图列“applicationid”的数据类型从未知更改为文本
although I already cast the value of applicationid column to text. it's still recognized as unkown datatype
虽然我已经将 applicationid 列的值转换为文本。它仍然被认为是未知的数据类型
'pointrewarding'::text
The alternative method of postgres conversion also didn't work.
postgres 转换的替代方法也不起作用。
CAST('pointrewarding' AS TEXT)
How to solve this problem.
如何解决这个问题呢。
回答by Mike Sherrill 'Cat Recall'
If you want to change the data type of a view's columns, you have to drop it, then create it.
如果要更改视图列的数据类型，必须先删除它，然后再创建它。
CREATE OR REPLACE VIEW .... The new query must generate the same columns that were generated by the existing view query (that is, the same column namesin the same orderand with the same data types), but it may add additional columns to the end of the list.
CREATE OR REPLACE VIEW .... 新查询必须生成与现有视图查询生成的列相同的列（即，相同的列名以相同的顺序和相同的数据类型），但它可能会添加额外的列到列表的末尾。
Emphasis added.
强调了。
