续集中的联想未按预期工作 [英] Associations in sequelize not working as intended
问题描述
我正在尝试输出嵌套关系，其中
I am attempting to output a nested relation where
Cat.hasMany（legs）
Cat.hasMany(legs)
Leg。 EmiratesTo（cat）
Leg.belongsTo(cat)
Leg.hasOne（paw）
Leg.hasOne(paw)
paw.hasMany（leg）
paw.hasMany(leg)
这是我的猫模型：
module.exports = (sequelize, DataTypes) => {
const Cat = sequelize.define('Cat', {
userId: {
type: DataTypes.STRING,
},
}, {});
Cat.associate = function (models) {
Cat.hasMany(models.Leg, {
foreignKey: 'catId',
as: 'legs',
});
};
return Cat;
};
我的腿模型：
module.exports = (sequelize, DataTypes) => {
const Leg = sequelize.define('Leg', {
originalValue: DataTypes.JSON,
newValue: DataTypes.JSON,
legId: DataTypes.INTEGER,
objectId: DataTypes.INTEGER,
pawId: DataTypes.INTEGER,
}, {});
Leg.associate = function (models) {
Leg.belongsTo(models.Cat, {
foreignKey: 'LegId',
onDelete: 'CASCADE',
});
Leg.hasOne(models.Paw, {
foreignKey: 'pawId',
});
};
return Leg;
};
这是我的爪子模型
module.exports = (sequelize, DataTypes) => {
const Paw = sequelize.define('Paw', {
pawType: DataTypes.STRING,
}, {});
Paw.associate = function (models) {
Paw.hasMany(models.Leg, {
foreignKey: 'pawId',
as: 'paws',
});
};
return Paw;
};
当前，当我查询Cat Table时，我的代码正在输出此内容
Currently My code is outputting this when i query the Cat Table
[
{
"id": 1,
"userId": "2wdfs",
"createdAt": "2018-04-14T20:12:47.112Z",
"updatedAt": "2018-04-14T20:12:47.112Z",
"legs": [
{
"id": 1,
"catId": 1,
"pawId": 1,
"createdAt": "2018-04-14T20:12:54.500Z",
"updatedAt": "2018-04-14T20:12:54.500Z"
}
]
}
]
但是，当我列出cat表中的所有内容时，我希望paws表中的pawType也存在。与此类似：
However I would like the pawType from the paws table to also be present when listing everything from the cat table. Something more along the lines of this:
[
{
"id": 1,
"userId": "2wdfs",
"createdAt": "2018-04-14T20:12:47.112Z",
"updatedAt": "2018-04-14T20:12:47.112Z",
"legs": [
{
"id": 1,
"catId": 1,
"paws" : [
{
"id": 1,
"pawType": "cute"
}
]
"createdAt": "2018-04-14T20:12:54.500Z",
"updatedAt": "2018-04-14T20:12:54.500Z"
}
]
}
]
此外，这是我用来检索猫的查询。
Additionally, Here is the query I am using to retrieve the Cats.
return Cat.findAll({ include: [{ model: Leg, as: 'legs',include [{model: Paw,}], }], })
这是返回的错误，
{ SequelizeDatabaseError: column legs->Paw.pawId does not exist
{ error: column legs->Paw.pawId does not exist
以及完整的SQL命令
sql: 'SELECT "Cat"."id", "Cat"."userId", "Cat"."createdAt", "Cat"."updatedAt", "legs"."id" AS "legs.id", "legs"."originalValue" AS "legs.originalValue", "legs"."newValue" AS "legs.newValue", "legs"."catId" AS "legs.catId", "legs"."objectId" AS "legs.objectId", "legs"."pawId" AS "legs.pawId", "legs"."createdAt" AS "legs.createdAt", "legs"."updatedAt" AS "legs.updatedAt", "legs->Paw"."id" AS "legs.Paw.id", "legs->Paw"."paw" AS "legs.Paw.paw", "legs->Paw"."pawId" AS "legs.Paw.pawId", "legs->Paw"."createdAt" AS "legs.Paw.createdAt", "legs->Paw"."updatedAt" AS "legs.Paw.updatedAt" FROM "Cats" AS "Cat" LEFT OUTER JOIN "Legs" AS "legs" ON "Cat"."id" = "legs"."catId" LEFT OUTER JOIN "Paws" AS "legs->Paw" ON "legs"."id" = "legs->Paw"."pawId";' },
推荐答案
有很多问题。我会尝试逐步解决它们。
There are many issues. I'll try to address them incrementally.
1）模型默认情况下，如果您未声明 primaryKey ，然后自动为您添加一个 id 列。因此 legId 并不是有用的列。
1) Models By default, if you do not declare a primaryKey, then sequelize automatically adds an id column for you. Thus legId isn't a useful column.
此外，如果您关联了模型，则 foreignKey 为您添加了引用，因此不应声明 pawId 。
Furthermore, if you associate a model, the foreignKey reference is added for you, thus pawId shouldn't be declared.
因此 Legs.js 应该修改为：
module.exports = (sequelize, DataTypes) => {
var Leg = sequelize.define('Leg', {
originalValue: DataTypes.JSON,
newValue: DataTypes.JSON,
objectId: DataTypes.INTEGER // not entirely sure what this is
})
Leg.associate = function (models) {
// associations
}
return Leg
}
以上内容为我提供了 pgAdmin 中的以下列：
The above gives me the following columns in pgAdmin:
2）关联
以下关联没有意义，并且应该会导致错误：
The following association doesn't make sense, and should cause an error:
Leg.hasOne(Paw)
Paw.hasMany(Leg)
Unhandled rejection Error: Cyclic dependency found. Legs is dependent of itself.
Dependency chain: Legs -> Paws => Legs
每个腿应该有一个 Paw ，因此我建议以下内容：
Each Leg should have one Paw, and thus I suggest the following:
Leg.associate = function (models) {
// Leg.belongsTo(models.Cat)
Leg.hasOne(models.Paw, {
foreignKey: 'pawId',
as: 'paw'
})
}
Paw.associate = function (models) {
Paw.belongsTo(models.Leg, {
as: 'leg' // note this changed to make more sense
foreignKey: 'pawId'
})
}
3）外键
Leg.belongsTo(models.Cat, {
foreignKey: 'catId', // this should match
onDelete: 'CASCADE'
})
Cat.hasMany(models.Leg, {
foreignKey: 'catId', // this should match
as: 'legs'
})
4）渴望加载
当渴望加载嵌套关联时，您必须 include 他们。您还应该使用作为别名来匹配您的模型关联：
When eager loading nested associations, you have to include them. You should also use as alias that matches your model associations:
Cat.findAll({
include: [{
model: Leg,
as: 'legs', // Cat.legs
include: [{
model: Paw,
as: 'paw' // Leg.paw instead of Leg.pawId
}]
}]
})
使用整个设置和上面的查询，我得到：
Using this entire setup and the above query, I obtain:
[
{
"id": 1,
"userId": "1",
"createdAt": "2018-04-15T11:22:59.888Z",
"updatedAt": "2018-04-15T11:22:59.888Z",
"legs": [
{
"id": 1,
"originalValue": null,
"newValue": null,
"objectId": null,
"createdAt": "2018-04-15T11:22:59.901Z",
"updatedAt": "2018-04-15T11:22:59.901Z",
"catId": 1,
"paw": {
"id": 1,
"pawType": null,
"createdAt": "2018-04-15T11:22:59.906Z",
"updatedAt": "2018-04-15T11:22:59.906Z",
"pawId": 1
}
}
]
}
]
额外
由于这显然是一种练习设置，因此您可以将 Paw 修改为 belongsToMany 关系（也许您用爪子把猫连起来了吗？），如下所示：
Because this is obviously a practice setup, you could modify Paw to be a belongsToMany relation (perhaps you have conjoined cats by the paw?) as follows:
Paw.associate = function (models) {
Paw.belongsToMany(models.Leg, {
foreignKey: 'pawId',
through: 'PawLegs // a through join table MUST be defined
})
}
这将是实现最初尝试使用的正确方法
This would be the correct way to implement what you initially tried to with
Leg.hasOne(paw)
paw.hasMany(leg)
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