postgres 不会掉落不为空

Question

我将 not null 放在主键列上，它会在我检查 table 的模式并且有 not null

后执行

table:

-- auto-generated definition
create table warehouses
(
    id_warehouse       serial      not null
        constraint warehouse_pkey
            primary key,
    responsible_person varchar(30) not null
);

要删除的脚本不为空：

alter table warehouses
    drop constraint warehouse_pkey;

alter table warehouses
    alter id_warehouse drop not null;

alter table warehouses
    add constraint warehouse_pkey
        primary key (id_warehouse);

Answer 1

根据此处的信息：

https://www.postgresql.org/docs/current/sql-createtable.html

PRIMARY KEY (column constraint)

The PRIMARY KEY constraint specifies that a column or columns of a table can contain only unique (non-duplicate), nonnull values. Only one primary key can be specified for a table, whether as a column constraint or a table constraint.

定义为 PRIMARY KEY 的列也将具有 NOT NULL 约束集。

postgres 不会掉落不为空

postgres doesn't drop not null

postgresql

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