"""add_river_cross_section

Revision ID: a2cfbc6c2673
Revises: e484105cc893
Create Date: 2025-07-12 01:35:26.959660

"""
from alembic import op
import sqlalchemy as sa


# revision identifiers, used by Alembic.
revision = 'a2cfbc6c2673'
down_revision = 'e484105cc893'
branch_labels = None
depends_on = None


def upgrade():
    """升级数据库到当前版本"""
    # ### commands auto generated by Alembic - please adjust! ###
    op.create_table('cross_section',
    sa.Column('id', sa.Integer(), autoincrement=True, nullable=False, comment='主键ID'),
    sa.Column('river_name', sa.String(length=50), nullable=False, comment='所属河流'),
    sa.Column('position', sa.String(length=100), nullable=False, comment='断面位置'),
    sa.Column('county', sa.String(length=50), nullable=False, comment='所属行政区'),
    sa.Column('longitude', sa.Float(), nullable=False, comment='经度坐标（精确到小数点后六位数）'),
    sa.Column('latitude', sa.Float(), nullable=False, comment='纬度坐标（精确到小数点后六位数）'),
    sa.Column('cd_concentration', sa.Float(), nullable=False, comment='镉浓度（mg/L）'),
    sa.PrimaryKeyConstraint('id')
    )
    # ### end Alembic commands ###


def downgrade():
    """将数据库降级到上一版本"""
    # ### commands auto generated by Alembic - please adjust! ###
    op.drop_table('cross_section')
    # ### end Alembic commands ###