我遇到了一个问题,我的主键序列与我的表行不同步。

也就是说,当我插入一个新行时,我得到一个重复的键错误,因为在串行数据类型中隐含的序列返回一个已经存在的数字。

这似乎是由于导入/恢复没有正确地维护序列造成的。


当前回答

如果您在加载自定义SQL数据进行初始化时看到此错误,另一种避免此错误的方法是:

而不是写:

INSERT INTO book (id, name, price) VALUES (1 , 'Alchemist' , 10),

从初始数据中删除id(主键)

INSERT INTO book (name, price) VALUES ('Alchemist' , 10),

这使Postgres序列保持同步!

其他回答

在下例中,表名为users,模式名为public(默认模式),请根据需要替换它。

1. 检查最大id:

SELECT MAX(id) FROM public.users;

2. 检查下一个值:

SELECT nextval('public."users_id_seq"');

3.如果下一个值小于最大id,重置它:

SELECT setval('public."users_id_seq"',
  (SELECT MAX(id) FROM public.users)
);

注意:

Nextval()将在返回当前值之前递增序列,而currval()将只返回当前值,如本文所述。

这个问题发生在我使用实体框架创建数据库,然后用初始数据播种数据库时,这使得序列不匹配。

我通过创建一个脚本来解决这个问题,在播种数据库后运行:

DO
$do$
DECLARE tablename text;
BEGIN
    -- change the where statments to include or exclude whatever tables you need
    FOR tablename IN SELECT table_name FROM information_schema.tables WHERE table_schema='public' AND table_type='BASE TABLE' AND table_name != '__EFMigrationsHistory'
        LOOP
            EXECUTE format('SELECT setval(pg_get_serial_sequence(''"%s"'', ''Id''), (SELECT MAX("Id") + 1 from "%s"))', tablename, tablename);
    END LOOP;
END
$do$

只需运行以下命令:

SELECT setval('my_table_seq', (SELECT max(id) FROM my_table));

这里有很多很好的答案。在重新加载Django数据库后,我也有同样的需求。

但我需要:

All in one功能 可以一次修复一个或多个模式吗 可以修复所有或只是一个表的时间 还想要一个很好的方式来确切地看到什么改变了,或没有改变

这似乎与最初的要求非常相似。 多亏了Baldiry和Mauro让我找到了正确的方向。

drop function IF EXISTS reset_sequences(text[], text) RESTRICT;
CREATE OR REPLACE FUNCTION reset_sequences(
    in_schema_name_list text[] = '{"django", "dbaas", "metrics", "monitor", "runner", "db_counts"}',
    in_table_name text = '%') RETURNS text[] as
$body$
  DECLARE changed_seqs text[];
  DECLARE sequence_defs RECORD; c integer ;
  BEGIN
    FOR sequence_defs IN
        select
          DISTINCT(ccu.table_name) as table_name,
          ccu.column_name as column_name,
          replace(replace(c.column_default,'''::regclass)',''),'nextval(''','') as sequence_name
          from information_schema.constraint_column_usage ccu,
               information_schema.columns c
          where ccu.table_schema = ANY(in_schema_name_list)
            and ccu.table_schema = c.table_schema
            AND c.table_name = ccu.table_name
            and c.table_name like in_table_name
            AND ccu.column_name = c.column_name
            AND c.column_default is not null
          ORDER BY sequence_name
   LOOP
      EXECUTE 'select max(' || sequence_defs.column_name || ') from ' || sequence_defs.table_name INTO c;
      IF c is null THEN c = 1; else c = c + 1; END IF;
      EXECUTE 'alter sequence ' || sequence_defs.sequence_name || ' restart  with ' || c;
      changed_seqs = array_append(changed_seqs, 'alter sequence ' || sequence_defs.sequence_name || ' restart with ' || c);
   END LOOP;
   changed_seqs = array_append(changed_seqs, 'Done');

   RETURN changed_seqs;
END
$body$ LANGUAGE plpgsql;

然后执行并查看更改运行:

select *
from unnest(reset_sequences('{"django", "dbaas", "metrics", "monitor", "runner", "db_counts"}'));

返回

activity_id_seq                          restart at 22
api_connection_info_id_seq               restart at 4
api_user_id_seq                          restart at 1
application_contact_id_seq               restart at 20
select 'SELECT SETVAL(' || seq [ 1] || ', COALESCE(MAX('||column_name||')+1, 1) ) FROM '||table_name||';'
from (
       SELECT table_name, column_name, column_default, regexp_match(column_default, '''.*''') as seq
       from information_schema.columns
       where column_default ilike 'nextval%'
     ) as sequense_query