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plantillas-proyectos/backend/alembic/versions/ca7d3c4e8b2a_add_transportation_id_sequences.py
2026-05-08 08:49:06 -06:00

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Python

"""add transportation id sequences
Revision ID: ca7d3c4e8b2a
Revises: b2c3d4e5f6a7
Create Date: 2026-05-08 08:34:00.000000
Crea las secuencias `a76.<tabla>_<id>_seq` que los servicios de catálogos de
transporte (transporter, vehicle, driver, trailer) referencian vía
`SELECT nextval(...)`. La migración es idempotente y reposiciona cada
secuencia a `MAX(<id>)` para no chocar con filas pre-existentes.
"""
from typing import Sequence, Union
from alembic import op
revision: str = "ca7d3c4e8b2a"
down_revision: Union[str, None] = "b2c3d4e5f6a7"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None
# (tabla, columna_id_sustituto) en el esquema a76. El nombre de secuencia
# resultante es `a76.<tabla>_<columna>_seq`, que es el patrón que los
# servicios ya consumen (ver transporters/vehicles/drivers/trailers services).
_SEQUENCE_TARGETS = (
("transporter", "transporter_id"),
("vehicle", "vehicle_id"),
("driver", "driver_id"),
("trailer", "trailer_id"),
)
def _seq_name(table: str, column: str) -> str:
return f"{table}_{column}_seq"
def upgrade() -> None:
for table, column in _SEQUENCE_TARGETS:
seq = _seq_name(table, column)
op.execute(
f'CREATE SEQUENCE IF NOT EXISTS a76."{seq}" '
f"AS BIGINT START WITH 1 INCREMENT BY 1"
)
# Reposicionar la secuencia al MAX(id) actual para evitar colisiones
# con datos ya cargados antes de existir la secuencia.
op.execute(
f"SELECT setval('a76.\"{seq}\"', "
f"GREATEST((SELECT COALESCE(MAX({column}), 0) FROM a76.{table}), 1), "
f"true)"
)
op.execute(
f'ALTER SEQUENCE a76."{seq}" OWNED BY a76.{table}.{column}'
)
op.execute(
f"ALTER TABLE a76.{table} "
f"ALTER COLUMN {column} SET DEFAULT nextval('a76.\"{seq}\"')"
)
def downgrade() -> None:
for table, column in _SEQUENCE_TARGETS:
seq = _seq_name(table, column)
op.execute(
f"ALTER TABLE a76.{table} ALTER COLUMN {column} DROP DEFAULT"
)
op.execute(f'DROP SEQUENCE IF EXISTS a76."{seq}"')