我有一个像这样的模型:
class Schedule(db.Model):
__tablename__ = 'schedule'
id = db.Column(db.Integer, primary_key=True)
student_id = db.Column(ARRAY(db.Integer, db.ForeignKey('student.id')))
然后我将student_id
列更改为以下内容:
student_id = db.Column(db.Integer, db.ForeignKey('student.id'))
以下是我的迁移文件代码片段:
from alembic import op
import sqlalchemy as sa
from sqlalchemy.dialects import postgresql
from sqlalchemy.dialects.postgresql import INTEGER
def upgrade():
# ### commands auto generated by Alembic - please adjust! ###
# ...
op.alter_column('schedule', 'student_id',
existing_type=postgresql.ARRAY(INTEGER()),
type_=sa.Integer(),
existing_nullable=True)
# ...
# ### end Alembic commands ###
当我尝试运行“db migrate”命令时,我收到了以下错误消息:
sqlalchemy.exc.ProgrammingError: (psycopg2.errors.DatatypeMismatch) column "student_id" cannot be cast automatically to type integer
HINT: You might need to specify "USING student_id::integer".
[SQL: 'ALTER TABLE schedule ALTER COLUMN student_id TYPE INTEGER ']
我的软件包版本如下:
Flask==0.12
alembic==0.8.10
Flask-Migrate==2.0.3
Flask-SQLAlchemy==2.1
SQLAlchemy==1.1.5
psycopg2==2.8.3
当我尝试使用以下命令直接在 SQL 上运行时:
ALTER TABLE schedule ALTER COLUMN student_id TYPE INTEGER;
我收到了以下错误信息:
ERROR: column "student_id" cannot be cast automatically to type integer
HINT: You might need to specify "USING student_id::integer".
SQL state: 42804
然后我尝试使用HINT
指令添加命令:
ALTER TABLE schedule ALTER COLUMN student_id TYPE INTEGER USING student_id::integer;
接着我遇到了这个错误:
ERROR: cannot cast type integer[] to integer
LINE 1: ...ER COLUMN student_id TYPE INTEGER USING student_id::integer;
^
SQL state: 42846
Character: 75
所以,我的问题是,这有什么问题吗?Alembic有问题还是我的代码出了问题? 如果可以的话,请给予帮助,谢谢 :)