Question

我目前被Django应用程序困在22号渔获物中。我必须改变专栏的类型,从变种字符改为 Integer,因为i m 正在从 UUIDs 移动到普通的旧的IDs(数据从未改变,因为它是物理常数 ) 。现在, Django扔了一个最初无法从VarChar投给Int的Fit, 所以我“帮助”了:

 ALTER TABLE glass_fill ALTER COLUMN id TYPE INTEGER USING CAST(id AS INT);

现在,它写道:

django.db.utils.DatabaseError: foreign key constraint "glass_fill_manufacturer_glass_fill_id_fkey" cannot be implemented
DETAIL:  Key columns "glass_fill_id" and "id" are of incompatible types: integer and character varying.

有什么想法吗?

注意: 玻璃_ fill_ manucacturer Table 尚未创建, 但 Django 试图在同步上尝试, 但失败了。

ALTER TABLE glass_fill ALTER COLUMN id TYPE INTEGER USING CAST(id AS INT);

线条没有如我想的那样更改列。

玻璃杯表图案:

-- Table: glass_fill

-- DROP TABLE glass_fill;

CREATE TABLE glass_fill
(
  id character varying(36) NOT NULL,
  name character varying(255),
  temperature real,
  density real,
  viscosity real,
  conductivity real,
  heat_capacity real,
  colour text,
  CONSTRAINT glass_fill_pkey PRIMARY KEY (id )
)
WITH (
  OIDS=FALSE
);

Answer 1

ALTER TABLE glass_fill_manufacturer 
ALTER COLUMN glass_fill_id TYPE INTEGER USING CAST(glass_fill_id AS INT)
;

我猜通过你的短信决哥会不知怎么做到但如果不做到的话

ALTER TABLE glass_fill_manufacturer 
drop constraint glass_fill_manufacturer_glass_fill_id_fkey
;

alter table glass_fill_manufacturer 
ADD constraint glass_fill_manufacturer_glass_fill_id_fkey 
foreign key (glass_fill_id) references glass_fill (id)
;

Answer 2

您应该采取以下行动:

Drop the constraints
Create a temporary table to hold mapping between old and new ids
Update glass_fill, returning the values into the temporary table
Update the referencing tables from the temporary table
Alter column types on all tables
Recreate the constraints

友情链接