Python/SQL Alchemy Migrate - "ValueError: zu viele Werte zum Entpacken" beim Migrieren von Änderungen in db

Question

Ich habe mehrere Modelle in SQLAlchemy geschrieben und ich habe gerade eine Ausnahme beim Ausführen meiner Migrations-Skripts gestartet: ValueError: zu viele Werte zu entpacken

Hier sind meine Modelle:

from app import db 

ROLE_USER = 0 
ROLE_ADMIN = 1 


class UserModel(db.Model): 
    __tablename__ = 'user' 
    id = db.Column(db.Integer, primary_key=True) 
    username = db.Column(db.String(25), index=True) 
    password = db.Column(db.String(50)) 
    email = db.Column(db.String(50), index=True, unique=True) 
    role = db.Column(db.SmallInteger, default=ROLE_USER) 

    def __repr__(self): 
     return '<User %r>' % (self.username) 


class ConferenceModel(db.Model): 
    __tablename__ = 'conference' 
    id = db.Column(db.Integer, primary_key=True) 
    name = db.Column(db.String(40), index=True, unique=True) 
    teams = db.relationship('TeamModel', backref='conference', lazy='dynamic') 

    def __repr__(self): 
     return '<Conference %r>' % (self.name) 


class TeamModel(db.Model): 
    __tablename__ = 'team' 
    id = db.Column(db.Integer, primary_key=True) 
    name = db.Column(db.String(50), index=True, unique=True) 
    conference_id = db.Column(db.Integer, db.ForeignKey('conference.id')) 
    players = db.relationship('PlayerModel', backref='team', lazy='dynamic') 

    def __repr__(self): 
     return '<Team %r>' % (self.name) 

class PlayerModel(db.Model): 
    __tablename__ = 'player' 
    id = db.Column(db.Integer, primary_key=True) 
    season = db.Column(db.String(4), index=True) 
    name = db.Column(db.String(75), index=True) 
    number = db.Column(db.String(3)) 
    position = db.Column(db.String(4)) 
    height = db.Column(db.Integer) 
    weight = db.Column(db.Integer) 
    academic_class = db.Column(db.String(2)) 
    hometown = db.Column(db.String(40)) 
    status = db.Column(db.SmallInteger) 
    team_id = db.Column(db.Integer, db.ForeignKey('team.id')) 

    def __repr__(self): 
     return '<player %r>' % (self.name) 


class GameModel(db.Model): 
    __tablename__ = 'game' 

    id = db.Column(db.Integer, primary_key=True) 
    espn_id = db.Column(db.Integer, index=True) 
    date_time = db.Column(db.DateTime) 
    location = db.Column(db.String(100)) 
    home_final = db.Column(db.Integer) 
    away_final = db.Column(db.Integer) 
    game_type = db.Column(db.Integer) 
    season = db.Column(db.Integer) 
    home_team_id = db.Column(db.Integer, db.ForeignKey('team.id')) 
    away_team_id = db.Column(db.Integer, db.ForeignKey('team.id')) 

    home_team = db.relationship("TeamModel", backref="homegames", foreign_keys=[home_team_id]) 
    away_team = db.relationship("TeamModel", backref="awaygames", foreign_keys=[away_team_id]) 


class ScoreDataModel(db.Model): 
    __tablename__ = 'scoredata' 

    id = db.Column(db.Integer, primary_key=True) 
    starter = db.Column(db.Boolean) 
    minutes_played = db.Column(db.Integer) 
    field_goals_made = db.Column(db.Integer) 
    field_goals_attempted = db.Column(db.Integer) 
    three_pointers_made = db.Column(db.Integer) 
    three_pointers_attempted = db.Column(db.Integer) 
    free_throws_made = db.Column(db.Integer) 
    free_throws_attempted = db.Column(db.Integer) 
    offensive_rebounds = db.Column(db.Integer) 
    rebounds = db.Column(db.Integer) 
    assists = db.Column(db.Integer) 
    steals = db.Column(db.Integer) 
    blocks = db.Column(db.Integer) 
    turnovers = db.Column(db.Integer) 
    personal_fouls = db.Column(db.Integer) 
    points = db.Column(db.Integer) 


    # Added the columns below and the migrate script blew up... 
    # I've taken them out and added other columns, but the error still presents 
    player_id = db.Column(db.Integer, db.ForeignKey('player.id')) 
    game_id = db.Column(db.Integer, db.ForeignKey('game.id')) 

    player = db.relationship("PlayerModel", backref="boxscores") 
    game = db.relationship("GameModel", backref="boxscore") 

Hier mein Migrate Skript (das frmo Miguel Grinberg Mega Flask Tutorial genommen wurde):

#!flask/bin/python 
import imp 
from migrate.versioning import api 
from app import db 
from config import SQLALCHEMY_DATABASE_URI 
from config import SQLALCHEMY_MIGRATE_REPO 
migration = SQLALCHEMY_MIGRATE_REPO + '/versions/%03d_migration.py' % (api.db_version(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO) + 1) 
tmp_module = imp.new_module('old_model') 
old_model = api.create_model(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO) 
exec old_model in tmp_module.__dict__ 
script = api.make_update_script_for_model(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO, tmp_module.meta, db.metadata) 
open(migration, "wt").write(script) 
api.upgrade(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO) 
print 'New migration saved as ' + migration 
print 'Current database version: ' + str(api.db_version(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)) 

Und h ere ist die Zurückverfolgungs:

/Users/johncaine/anaconda/bin/python /Volumes/Spano/Dropbox/Dropbox/eclipse-workspace/CAUDLE/src/caudle/caudle/db_migrate.py 
Traceback (most recent call last): 
    File "/Volumes/Spano/Dropbox/Dropbox/eclipse-workspace/CAUDLE/src/caudle/caudle/db_migrate.py", line 11, in <module> 
    script = api.make_update_script_for_model(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO, tmp_module.meta, db.metadata) 
    File "<string>", line 2, in make_update_script_for_model 
    File "/Users/johncaine/anaconda/lib/python2.7/site-packages/migrate/versioning/util/__init__.py", line 89, in catch_known_errors 
    return f(*a, **kw) 
    File "<string>", line 2, in make_update_script_for_model 
    File "/Users/johncaine/anaconda/lib/python2.7/site-packages/migrate/versioning/util/__init__.py", line 159, in with_engine 
    return f(*a, **kw) 
    File "/Users/johncaine/anaconda/lib/python2.7/site-packages/migrate/versioning/api.py", line 321, in make_update_script_for_model 
    engine, oldmodel, model, repository, **opts) 
    File "/Users/johncaine/anaconda/lib/python2.7/site-packages/migrate/versioning/script/py.py", line 69, in make_update_script_for_model 
    genmodel.ModelGenerator(diff,engine).genB2AMigration() 
    File "/Users/johncaine/anaconda/lib/python2.7/site-packages/migrate/versioning/genmodel.py", line 197, in genB2AMigration 
    for modelCol, databaseCol, modelDecl, databaseDecl in td.columns_different: 
ValueError: too many values to unpack 

Ich glaube, die einzige Änderung, die ich machte den ScoreDataModel wurde hinzugefügt, wenn dieser gestartete Sprengung. Ich kann nicht darauf zurückkommen, wo ich das beheben kann.

Answer 1

Ich stieß auf das gleiche Problem mit sqlalchemy + mysql. Ich hatte boolesche Felder in meinem Modell und sie wurden in mysql mit smallint erstellt. Im Migrationsskript vergleicht es den Modell-Datentyp mit dem Schema-Datentyp (in meinem Fall von mysql). sqlalchemy übersetzt den booleschen Datentyp standardmäßig in tinyint und in mysql wird das Schema mit smallint erstellt.

Das Migrations-Skript löst den angegebenen Fehler aus, wenn dieser Unterschied zwischen Modell und Schema erkannt wird. Ich habe meinen Modell-Datentyp in db.SmallInteger von db.Boolean geändert, um dies zu lösen.