[英]How to build model with sequelize for belong to many association
這就是我在Country.js中寫的(除了數據類型與User.js完全相同):
module.exports = function(sequelize, DataTypes) {
const Country = sequelize.define('country',
{
id: {
type: DataTypes.INTEGER,
primaryKey: true,
autoIncrement: true
},
code: {
type: DataTypes.INTEGER
},
alpha2: {
type: DataTypes.STRING
},
alpha3: {
type: DataTypes.STRING
},
name_en: {
type: DataTypes.STRING
},
name_fr: {
type: DataTypes.STRING
}
},
{
freezeTableName: true,
timestamps: false
});
Country.associate = ( models ) => {
models.Country.belongsToMany(models.User, {
through: 'country_user',
as: 'user',
foreignKey: 'id_country'
});
};
return Country;
}
這是我的查詢:
router.get('/thisuserCountries', function(req, res, next){
User(db, Sequelize.DataTypes).findOne({
include: [{
model: Country(db, Sequelize.DataTypes),
as: 'countries',
required: false,
attributes: ['id'],
}],
where: {
email: 'jerome.charlat@gmail.com'
}
})
.then(user => {
if(user) {
res.json(user)
}
else {
res.send('User does not exist')
}
})
.catch(err => {
res.send('error: ' + err)
})
})
這是我的db.js:
const Sequelize = require('sequelize')
const db = new Sequelize('travel_memories', 'root', '', {
host: 'localhost',
dialect: 'mysql',
port: 3306
})
db
.authenticate()
.then(() => {
console.log('Connection has been established successfully.');
})
.catch(err => {
console.error('Unable to connect to the database:', err);
});
const models = {
Country: db.import('../models/Country'),
User: db.import('../models/User'),
CountryUserJoin: db.import('../models/Country_user')
};
Object.keys(models).forEach((modelName) => {
if('associate' in models[modelName]){
models[modelName].associate(models);
}
});
module.exports = db
郵遞員說:錯誤SequelizeEagerLoadingError:國家未與用戶關聯!
但是,當我在每個模型中關聯表時,我應該在through參數中寫入模型User_country。 所以我試圖寫一些像:
Country.associate = ( models ) => {
models.Country.belongsToMany(models.User, {
through: models.Country_user,
as: 'user',
foreignKey: 'id_country'
});
};
控制台說,當我啟動服務器時,在查詢任何內容之前:
SequelizeAssociationError:country.belongsToMany(user)需要通過選項,傳遞字符串或模型。
所以我被封鎖了。 我使用文檔中的示例來編寫與models.foo的關聯。 但是實際上模型無處不在。
再次感謝你的幫助 !
沒有太多關於此的文檔,但是在這里它說您在查詢或選擇“多對多”屬性時應使用through
選項,如下所示:
...
User(db, Sequelize.DataTypes).findOne({
include: [{
model: Country(db, Sequelize.DataTypes),
as: 'countries',
required: false,
through: {
attributes: ['id']
}
}],
where: {
email: 'jerome.charlat@gmail.com'
}
})
...
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