[英]Empty array as PostgreSQL array column default value
I have a defined an array field in postgresql 9.4 database:我在 postgresql 9.4 数据库中定义了一个数组字段:
character varying(64)[]
Can I have an empty array eg {} for default value of that field?我可以有一个空数组,例如 {} 作为该字段的默认值吗? What will be the syntax for setting so?
设置的语法是什么?
I'm getting following error in case of setting just brackets {}:如果只设置括号 {},我会收到以下错误:
SQL error:
ERROR: syntax error at or near "{"
LINE 1: ...public"."accounts" ALTER COLUMN "pwd_history" SET DEFAULT {}
^
In statement:
ALTER TABLE "public"."accounts" ALTER COLUMN "pwd_history" SET DEFAULT {}
You need to use the explicit array
initializer and cast that to the correct type:您需要使用显式
array
初始值设定项并将其转换为正确的类型:
ALTER TABLE public.accounts
ALTER COLUMN pwd_history SET DEFAULT array[]::varchar[];
I tested both the accepted answer and the one from the comments.我测试了接受的答案和评论中的答案。 They both work.
他们都工作。
I'll graduate the comments to an answer as it's my preferred syntax.我会将评论归结为答案,因为这是我的首选语法。 🙂
🙂
ALTER TABLE public.accounts
ALTER COLUMN pwd_history SET DEFAULT '{}';
It threw an error where it can not find SET
.它在找不到
SET
地方抛出了一个错误。 This worked for me.这对我有用。
ALTER TABLE public.accounts
ALTER COLUMN pwd_history DEFAULT array[]::varchar[];
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