Question

我安装了postgresql并创建了一个数据库。当我运行rake db：migrate时，虽然我遇到以下错误：

[newuser@Freenaut flights1percent{master}]$ rake db:migrate --trace
** Invoke db:migrate (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute db:migrate
== CreatePeople: migrating ===================================================
-- create_table(:people)
NOTICE: CREATE TABLE will create implicit sequence "people_id_seq" for serial column "people.id"
rake aborted!
An error has occurred, this and all later migrations canceled:

PGError: ERROR: relation "people" already exists
: CREATE TABLE "people" ("id" serial primary key, "created_at" timestamp, "updated_at" timestamp)

这是一个奇怪的错误，因为错误消息表明此表已存在。但是，我知道它不应该像我刚创建数据库那样。那么这里出了什么问题？

Answer 1

除非表确实存在，否则不会发生这种情况。可能是您在运行迁移之前将表创建为测试的一部分吗？

我在8.4分贝上运行你的创建表，这就是我得到的：

CREATE TABLE "people" ("id" serial primary key, "created_at" timestamp, "updated_at" timestamp);
   NOTICE:  CREATE TABLE will create implicit sequence "people_id_seq" for serial column "people.id"
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "people_pkey" for table "people"
CREATE TABLE

然后我再次运行它并收到您所做的相同错误消息：

CREATE TABLE "people" ("id" serial primary key, "created_at" timestamp, "updated_at" timestamp);
NOTICE:  CREATE TABLE will create implicit sequence "people_id_seq1" for serial column "people.id"
ERROR:  relation "people" already exists

无法在Rails中使用Postgresql运行迁移

1 个答案: