Migrate doesn't create onupdate value

[MyDuan]

problem:

• when I use flask db migrate to create migrations file, the onupdate doesn't create in the migration file in ./migration/versions/7a31061397a7_.py

model definition

class Company(db.Model):

    __tablename__ = "company_master"
    id = Column(Integer, primary_key=True, autoincrement=True)
    name = Column("name", String(100), nullable=False)
    post_code = Column("post_code", String(100), nullable=False)
    created_at = Column("created_at", DateTime(timezone=True), server_default=func.now(), nullable=True)
    updated_at = Column("updated_at", DateTime(timezone=True), server_default=func.now(), onupdate=func.now(), nullable=True)

    def __init__(self):
        self.id = id
        self.name = name
        self.post_code = post_code
        self.created_at = created_at
        self.updated_at = updated_at

The generated migration file

from alembic import op
import sqlalchemy as sa


# revision identifiers, used by Alembic.
revision = '7a31061397a7'
down_revision = None
branch_labels = None
depends_on = None


def upgrade():
    # ### commands auto generated by Alembic - please adjust! ###
    op.create_table('company_master',
    sa.Column('id', sa.Integer(), autoincrement=True, nullable=False),
    sa.Column('name', sa.String(length=100), nullable=False),
    sa.Column('post_code', sa.String(length=100), nullable=False),
    sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=True),
    sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=True),
    sa.PrimaryKeyConstraint('id')
    )

• the onupdate didn't create.

where is the problem.

[miguelgrinberg]

Flask-Migrate is a lightweight wrapper for Alembic, so your problem does not really apply to this project.

That said, the onupdate attribute is an ORM attribute, it does not need to be set on the database.