Question

如何将sqlAlchemy配置为不在烧瓶sqlAlchemy中创建表？

我仅使用flask-sqlalchemy模型的功能，但不会创建表。

如何配置它？

因为我想在sql View中使用，如果运行db.create_all（），则View变为表。

谢谢。

这是一个视图！

# -*- coding: utf-8 -*-
from settings.dataBase import CRUDMixin, db


class ViewExample(db.Model, CRUDMixin):
    __tablename__ = "view_example"

    id = db.Column(db.Integer, primary_key=True, nullable=False)
    name = db.Column(db.String(50))
    title = db.Column(db.String(100))
    is_albums = db.Column(db.Integer)
    is_attach = db.Column(db.Integer)
    is_spec = db.Column(db.Integer)
    sort_id = db.Column(db.Integer)

    def __init__(self, **kwargs):
        for key, value in kwargs.items():
            setattr(self, key, value)

    def __str__(self):
        return 'id : %s' % self.id

我找到一个例子，但是我不知道如何在flask-sqlalchemy中使用。无菌蒸馏化学文件： https://alembic.sqlalchemy.org/en/latest/cookbook.html#don-t-emit-create-table-statements-for-views

烧瓶迁移env.py 我添加了一个include_object函数，但没有得到is_view。

from __future__ import with_statement

import logging
from logging.config import fileConfig

from sqlalchemy import engine_from_config
from sqlalchemy import pool

from alembic import context

# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
config = context.config

# Interpret the config file for Python logging.
# This line sets up loggers basically.
fileConfig(config.config_file_name)
logger = logging.getLogger('alembic.env')

# add your model's MetaData object here
# for 'autogenerate' support
# from myapp import mymodel
# target_metadata = mymodel.Base.metadata
from flask import current_app

config.set_main_option(
    'sqlalchemy.url', current_app.config.get(
        'SQLALCHEMY_DATABASE_URI').replace('%', '%%'))
target_metadata = current_app.extensions['migrate'].db.metadata


# other values from the config, defined by the needs of env.py,
# can be acquired:
# my_important_option = config.get_main_option("my_important_option")
# ... etc.
def include_object(object, name, type_, reflected, compare_to):
    """
    Exclude views from Alembic's consideration.
    """
    print(object.info)
    return not object.info.get('is_view', False)


def run_migrations_offline():
    """Run migrations in 'offline' mode.

    This configures the context with just a URL
    and not an Engine, though an Engine is acceptable
    here as well.  By skipping the Engine creation
    we don't even need a DBAPI to be available.

    Calls to context.execute() here emit the given string to the
    script output.

    """
    url = config.get_main_option("sqlalchemy.url")
    context.configure(
        url=url, target_metadata=target_metadata, literal_binds=True,
    )

    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online():
    """Run migrations in 'online' mode.

    In this scenario we need to create an Engine
    and associate a connection with the context.

    """

    # this callback is used to prevent an auto-migration from being generated
    # when there are no changes to the schema
    # reference: http://alembic.zzzcomputing.com/en/latest/cookbook.html
    def process_revision_directives(context, revision, directives):
        if getattr(config.cmd_opts, 'autogenerate', False):
            script = directives[0]
            if script.upgrade_ops.is_empty():
                directives[:] = []
                logger.info('No changes in schema detected.')

    connectable = engine_from_config(
        config.get_section(config.config_ini_section),
        prefix='sqlalchemy.',
        poolclass=pool.NullPool,
    )

    with connectable.connect() as connection:
        context.configure(
            connection=connection,
            target_metadata=target_metadata,
            include_object=include_object,# add 
            process_revision_directives=process_revision_directives,
            **current_app.extensions['migrate'].configure_args
        )

        with context.begin_transaction():
            context.run_migrations()


if context.is_offline_mode():
    run_migrations_offline()
else:
    run_migrations_online()

添加__table_args__ = { "info": dict(is_view=True)}很好。

class ViewExample(db.Model, CRUDMixin):
    __tablename__ = "view_example"
    __table_args__ = { "info": dict(is_view=True)} # add

谢谢！这个问题已经解决了。

Answer 1

您可以在不想创建的模型中添加__abstract__ = True

如何配置模型以不在烧瓶sqlAlchemy中创建表？

1 个答案: