基础模型

Lucid 数据模型继承 Base Model 来获得与数据库表交互的属性和方法。

import { BaseModel } from '@ioc:Adonis/Lucid/Orm'

class User extends BaseModel {
}

模型适配器选项

许多模型方法都可以使用 模型选项 . 我们只在这里写一次，然后会在其他地方使用参考。

const modelOptions = {
  client: await Database.transaction(),
  connection: 'pg',
  profiler: profiler
}

所有配置都是可选的

• client 数据库连接实例 查询客户端 。大多数情况你会传入 事务客户端 。
• connection 对已注册连接名称的引用。当你有多个连接并希望指定连接时此参数非常有用。
• profiler 分析器实例。

静态属性/方法

静态引导

引导模型。 由于 JavaScript 类的继承对于静态属性来说并不是那么友好。 我们需要一个自定义的“启动”阶段来确保一切都按预期进行。

User.boot()

引导完成

Abel94 翻译于 1年前

0 重译

由 gyp719 审阅

A boolean to know if a model has been booted or not.

class User extends BaseModel {
  public static boot () {
    if (this.booted) {
      return
    }

    super.boot()
  }
}

static before

Define a before hook for a specific event.

public static boot () {
  if (this.booted) {
    return
  }

  super.boot()
  this.before('create', (user) => {
  })
}

static after

Define an after hook for a specific event.

public static boot () {
  if (this.booted) {
    return
  }

  super.boot()
  this.after('create', (user) => {
  })
}

Another (preferred) option is to make use of the decorators to mark model static methods as hooks.

import {
  BaseModel,
  beforeSave,
} from '@ioc:Adonis/Lucid/Orm'

class User extends BaseModel {
  @beforeSave()
  public static hashPassword(user: User) {
  }
}

static create

Create a new model instance and persist it to the database right away.

const user = await User.create({
  email: 'virk@adonisjs.com',
  password: 'secret',
})

The method accepts a total of three arguments.

• data: The data to persist to the database

• options: Optionally define the model adapter options .

• allowExtraProperties: A boolean to allow passing extra properties in the data object. When set to false, the method will raise an exception when the data properties are not marked as columns.

• ---

static createMany

Create multiple instances of a model and persist them to the database. The createMany method accepts the same options as the create method.

• One insert query is issued for each model instance to ensure that we execute the lifecycle hooks for every individual instance.
• All the insert queries are internally wrapped inside a transaction. In case of an error, everything will be rolled back.

const user = await User.createMany([
  {
    email: 'virk@adonisjs.com',
    password: 'secret',
  },
  {
    email: 'romain@adonisjs.com',
    password: 'secret',
  },
])

static find

Find a row from the database using the model primary key. If a row exists it will be hydrated to the model instance, otherwise null is returned.

const user = await User.find(1)
if (!user) {
  return
}

console.log(user instanceof User)

The method accepts a total of two arguments.

• value: The primary key value.

• options: Optionally define the model adapter options .

• ---

static findOrFail

Same as the find method. But instead of returning null it will raise an exception when the row doesn't exists.

The findOrFail method accepts the same options as the find method.

const user = await User.findOrFail(1)

static findBy

Find a row inside the database by using a key-value pair. If a row exists it will be hydrated to the model instance, otherwise null is returned.

const user = await User.findBy('email', 'virk@adonisjs.com')

The method accepts a total of three arguments.

• columName: The column name to use in the where condition.

• value: The value for the column.

• options: Optionally define the model adapter options .

• ---

static findByOrFail

Same as the findBy method. But instead of returning null it will raise an exception when the row doesn't exists.

The findByOrFail method accepts the same options as the findBy method.

const user = await User.findByOrFail('email', 'virk@adonisjs.com')

static first

Returns the first row from the database. If a row exists it will be hydrated to the model instance, otherwise null is returned.

The first method relies on the default order of the underlying database engine.

const user = await User.first()

The method accepts a single arguments as the model adapter options .

static firstOrFail

Same as the first method. But instead of returning null it will raise an exception when the row doesn't exists.

const user = await User.firstOrFail()

The method accepts a single arguments as the model adapter options .

static findMany

Find multiple model instances of an array of values for the model primary key. For example:

const users = await User.findMany([1, 2, 3])

• The results will be order by the primary key in desc order.

• Internally, the method uses the where in SQL clause and always returns an array.

• Optionally, you can also pass model adapter options as the second argument.

• ---

static firstOrNew

Returns an existing row from the database or creates a local instance of the model, when row for search criteria is not found.

const searchCriteria = {
  email: 'virk@adonisjs.com',
}

const savePayload = {
  name: 'Virk',
  email: 'virk@adonisjs.com',
  password: 'secret'
}

const user = await User.firstOrNew(searchCriteria, savePayload)

if (user.$isPersisted) {
  // user exists in the database
} else {
  // un-persisted user instance
}

The method accepts a total of four arguments.

• searchCriteria: Values to use for the select statement.

• savePayload: Values to use to create a new model instance. Also we merge the searchCriteria with the save payload object.

• options: Optionally, define the model adapter options .

• allowExtraProperties: A boolean to allow passing extra properties in the data object. When set to false, the method will raise an exception when the data properties are not marked as columns.

• ---

static firstOrCreate

The firstOrCreate is similar to the firstOrNew method. However, instead of just creating a local model instance. The firstOrCreate method also performs the insert query.

The method accepts the same options as the firstOrNew method.

const user = await User.firstOrCreate(searchCriteria, savePayload)

if (user.$isLocal) {
  // no rows found in db. Hence a new one is created
} else {
  // existing db row
}

static updateOrCreate

The updateOrCreate method updates the existing row or creates a new one. The method accepts the same options as the firstOrNew method.

This method obtains an "UPDATE lock" on the row during the select. This is done to avoid concurrent reads from getting the old values when the row is in the middle of being updated.

const searchCriteria = {
  id: user.id
}

const savePayload = {
  total: getTotalFromSomeWhere()
}

const cart = await Cart.updateOrCreate(searchCriteria, savePayload)

static fetchOrNewUpMany

The fetchOrNewUpMany method is similar to the firstOrNew method. However, it operates on multiple rows.

const keyForSearch = 'email'
const payload = [
  {
    email: 'virk@adonisjs.com',
    name: 'Virk',
  },
  {
    email: 'romain@adonisjs.com',
    name: 'Romain',
  }
]

const users = await User.fetchOrNewUpMany(keyForSearch, payload)

for (let user of users) {
  if (user.$isPersisted) {
    // existing row in the database
  } else {
    // local instance
  }
}

In the above example, Lucid will search for existing users by their email (keyForSearch). For missing rows a new local instance of the model will be created.

The method accepts the same options as the firstOrNew method.

static fetchOrCreateMany

The fetchOrCreateMany method is similar to the firstOrCreate method. However, it operates on multiple rows.

const keyForSearch = 'email'
const payload = [
  {
    email: 'virk@adonisjs.com',
    name: 'Virk',
  },
  {
    email: 'romain@adonisjs.com',
    name: 'Romain',
  }
]

const users = await User.fetchOrCreateMany(keyForSearch, payload)

for (let user of users) {
  if (user.$isLocal) {
    // local+persisted instance
  } else {
    // existing row in the database
  }
}

The method accepts the same options as the firstOrNew method.

static updateOrCreateMany

The updateOrCreateMany method is similar to the updateOrCreate method. However, it operates on multiple rows.

This method obtains an "UPDATE lock" on the row during the select. This is done to avoid concurrent reads from getting the old values when the row is in the middle of being updated.

const keyForSearch = 'email'
const payload = [
  {
    email: 'virk@adonisjs.com',
    name: 'Virk',
  },
  {
    email: 'romain@adonisjs.com',
    name: 'Romain',
  }
]

const users = await User.updateOrCreateMany(keyForSearch, payload)

The method accepts the same options as the firstOrNew method.

static all

A shortcut method to fetch all the rows from a given database table. The rows are sorted in descending order by the primary key.

const users = await User.all()

Optionally, you can also pass model adapter options as an argument to the all method.

static query

Returns an instance of the model query builder . Unlike the standard query builder, the result of the model query builder is an array of model instances.

const users = await User
  .query()
  .where('age', '>', 18)
  .orderBy('id', 'desc')
  .limit(20)

Optionally, you can also pass model options as an argument to the query method.

static truncate

A shortcut to truncate the database table. . Optionally you can also cascade foreign key references.

await User.truncate()

// cascade
await User.truncate(true)

// custom connection
await User.truncate(true, {
  connection: 'pg',
})

Optionally, you can also pass model options as the 2nd argument.

static primaryKey

Define a custom primary for the model. It defaults to the id column.

class User extends BaseModel {
  public static primaryKey = 'uuid'
}

static selfAssignPrimaryKey

A boolean to notify Lucid that you will self assign the primary key locally in your application and does not rely on the database generate one for you.

A great example of this is using the UUID as the primary key and generating them locally in your JavaScript code.

class User extends BaseModel {
  public static selfAssignPrimaryKey = true

  @column({ isPrimary: true })
  public userId: string
}

const user = new User()
user.userId = uuid.v4()

await user.save()

static connection

Define a custom database connection for the model.

DO NOT use this property to switch the connection at runtime. This property is only to define a static connection name that remains same through out the lifecycle of the application.

class User extends BaseModel {
  public static connection = 'pg'
}

static table

Define a custom database table. By default, the table name is generated using the NamingStrategy.tableName method.

class User extends BaseModel {
  public static table = 'my_users'
}

static namingStrategy

Reference to the NamingStrategy . By default, the SnakeCaseNamingStrategy is used. However, you can override it globally or for a single model.

static $adapter

Reference to the underlying Adapter . Adapter works as a bridge between the model class and the database. Models directly do not rely on the Database.

static $hooks

Reference to the registered hooks. It value is a reference to the @poppinss/hooks package. You must use the before and after methods or decorators to define the model hooks.

static $columnsDefinitions

The $columnsDefinitions property is an ES6 Map of the model column name and its meta data. For example:

Map {
  'id' => {
    columnName: 'id',
    serializeAs: 'id',
    isPrimary: true
  }
}

The column meta data can be modified using the @column decorator.

class User extends BaseModel {
  @column({ columnName: 'user_id' })
  public id: number
}

static $computedDefinitions

The $computedDefinitions property is an ES6 Map of the model computed property name and its meta data. For example:

Map {
  'postsCount' => {
    serializeAs: 'postsCount'
  }
}

The computed meta data can be modified using the @computed decorator.

static $relationsDefinitions

The $relationsDefinitions property is an ES6 Map of the model relationships. The key is the relationship name and value is the instance of the relationship . For example:

Map {
  'profile' => HasOne {
    relationName: 'profile',
    relatedModel: [Function (anonymous)],
    options: { relatedModel: [Function (anonymous)] },
    model: [class User extends BaseModel] {
      booted: true,
      primaryKey: 'id',
      table: 'users'
    },
    type: 'hasOne',
    booted: false,
    serializeAs: 'profile',
    onQueryHook: undefined
  }
}

static $createFromAdapterResult

Create model instance by consuming the database results. The method handles the use case where the column name in the database is different from the property name defined in the model.

class User extends BaseModel {
  @column({ columnName: 'full_name' })
  public fullName: string
}

const user = User.$createFromAdapterResult({
  id: 1,
  full_name: 'Harminder Virk',
})

Optionally you can also pass the sideloaded properties and model options.

const data = {
  id: 1,
  full_name: 'Harminder Virk',
}

const sideloaded = {
  currentUser: auth.user
}

const options = {
  // Instance will use this query client moving forward
  client: Database.connection('pg')
}

const user = User.$createFromAdapterResult(data, sideloaded, options)

static $createMultipleFromAdapterResult

Same as $createFromAdapterResult, but allows creating multiple model instances.

User.$createFromAdapterResult([
  {
    id: 1,
    full_name: 'Harminder Virk',
  },
  {
    id: 2,
    full_name: 'Romain Lanz',
  }
])

static $addColumn

Define a model column. The @column decorator uses this method to mark a property as a column.

Model properties which are not marked as columns are never inserted to the database and also ignored when returned by a select call.

User.$addColumn('id', {})

Optionally, you can also define column meta-data.

User.$addColumn('id', {
  serializeAs: 'id',
  isPrimary: true,
  columnName: 'id',
})

static $hasColumn

Find if a column with the given name exists on the model or not.

User.$hasColumn('id')

static $getColumn

Returns the meta data for a given column.

if(User.$hasColumn('id')) {
  User.$getColumn('id')
}

static $addComputed

Mark a class property as a computed property. The @computed decorator uses this method to mark a property as computed.

User.$addComputed('postsCount', {
  serializeAs: 'posts_count',
})

static $hasComputed

Find if a computed property with the given name exists on the model or not.

User.$hasComputed('postsCount')

static $getComputed

Returns the meta data for a given computed property.

if(User.$hasComputed('id')) {
  User.$getComputed('id')
}

static $addRelation

Add a new relationship to the model. The relationship decorators calls this method behind the scene to mark a property as a relationship.

User.$addRelation(
  'posts',
  'hasMany',
  () => Post,
  {},
)

Additional options can be passed as the fourth argument.

User.$addRelation(
  'posts',
  'hasMany',
  () => Post,
  {
    localKey: 'id',
    foreignKey: 'user_uuid',
  },
)

static $hasRelation

Find if a relationship exists.

User.$hasRelation('posts')

static $getRelation

Returns the relationship instance for a pre-registered relationship.

if (User.$hasRelation('profile')) {
  User.$getRelation('profile')
}

Instance properties/methods

fill

The fill method allows you define the model attributes as an object. For example:

const user = new User()
user.fill({
  email: 'virk@adonisjs.com',
  name: 'virk',
  password: 'secret'
})

console.log(user.email)
console.log(user.name)
console.log(user.password)

The fill method replaces the existing attributes with the newly defined attributes.

merge

The merge method also accepts an object of attributes. However, instead of replacing the existing attributes, it performs a deep merge.

const user = new User()
user.email = 'virk@adonisjs.com'

user.merge({
  name: 'virk',
  password: 'secret'
})

console.log(user.email) // virk@adonisjs.com

save

Persist the model instance to the database. The save method performs an update when the model instance has already been persisted, otherwise an insert query is executed.

const user = new User()

user.merge({
  name: 'virk',
  email: 'virk@adonisjs.com',
  password: 'secret'
})

console.log(user.$isPersisted) // false
console.log(user.$isLocal) // true

await user.save()

console.log(user.$isPersisted) // true
console.log(user.$isLocal) // true

delete

Delete the row inside the database and freeze the model instance for further modifications. However, the instance can still be used for reading values.

const user = await User.find(1)
if (user) {
  await user.delete()

  console.log(user.$isDeleted) // true
}

refresh

Refresh the model instance by hydrating its attributes with the values inside the database.

You will find this method helpful when your columns have default values defined at the database level and you want to fetch them right after the insert query.

const user = await User.create({
  email: 'virk@adonisjs.com',
  password: 'secret'
})

await user.refresh() // "select * from users where id = user.id"

$attributes

The $attributes object is the key-value pair of model properties using the @column decorator.

The object is maintained internally to distinguish between the model regular properties and its columns. Consider the following example:

class User extends Model {
  @column({ isPrimary: true })
  public id: number

  @column()
  public fullName: string

  @column()
  public password: string

  public get initials() {
    const [firstName, lastName] = this.fullName.split(' ')

    if (!lastName) {
      return firstName.charAt(0).toUpperCase()
    }

    return `${firstName.charAt(0).toUpperCase()}${lastName.charAt(0).toUpperCase()}`
  }
}

Lets create a local instance of the model.

const user = new User()
user.fullName = 'Harminder Virk'
user.password = 'secret'

console.log(user.$attributes) // { fullName, password }

The $attributes object will not have the initials property, since it is not using the @column decorator.

How does $attributes object gets populated?

We make use of ES6 Proxies behind the scenes to populate the $attributes object. Here is the implementation of the Proxy handler.

$original

The $original object is a key-value pair of properties fetched from the database. The $original object is used to find the diff against the $attributes.

const user = await User.find(1)

console.log(user.$original === user.$attributes) // true
console.log(user.$isDirty) // false

user.fullName = 'Harminder Virk'
console.log(user.$isDirty) // true
console.log(user.$dirty) // diff between $original and $attributes

await user.save() // persist and update $original

console.log(user.$isDirty) // false

$preloaded

An object of preloaded relationships.

const user = await User.query().preload('profile').first()

console.log(user.$preloaded) // { profile: Profile }

$extras

The $extras are the values that are computed on the fly for a given model instance(s). For example: You fetch all the posts and a count of comments received on every post. The postsCount value we moved to $extras object, as it is not a database column.

const posts = await Post.query().withCount('comments')

posts.forEach((post) => {
  console.log(posts.$extras)
})

$primaryKeyValue

Value for the column marked as a primary key. For example:

class User extends BaseModel {
  @column({ isPrimary: true })
  public userId: number
}

const user = new User()
user.userId = 1

user.$primaryKeyValue // 1

The user.$primaryKeyValue will return the value of the userId property as it is marked as a primary key.

$getQueryFor

The BaseModel makes use of the model query builder and the insert query builder to run insert, update, delete and refresh queries.

It makes use of the $getQueryFor method to return the appropriate query builder for a given action. You can override this method, if you want to self construct the query builder for the above mentioned actions.

import { QueryClientContract } from '@ioc:Adonis/Lucid/Database'
import { BaseModel } from '@ioc:Adonis/Lucid/Orm'

class User extends BaseModel {
  public $getQueryFor(
    action: 'insert' | 'update' | 'delete' | 'refresh',
    client: QueryClientContract,
  ) {
    if (action === 'insert') {
      return client.insertQuery().table(User.table)
    }

    return client.modelQuery(User).where('id', this.$primaryKeyValue)
  }
}

$sideloaded

The $sideloaded properties are passed via the query builder to the model instances. A great example of $sideloaded properties is to pass down the currently logged in user to the model instance.

class Post extends BaseModel {
  @column({ isPrimary: true })
  public id: number

  @column()
  public userId: number

  @column()
  public title: number

  public get ownedByCurrentUser() {
    if (!this.$sideloaded) {
      return false
    }
    return this.$sideloaded.userId = this.userId
  }
}

In the above example, the ownedByCurrentUser relies on the $sideloaded.userId property to know if the post is owned by the current user or not.

Now, you can pass the userId to the model instances using the sideload method.

const posts = await Post
  .query()
  .sideload({ userId: auth.user.id })

posts.forEach((post) => {
  console.log(post.ownedByCurrentUser)
})

$isPersisted

Find if the model instance has been persisted to the database or not.

const user = new User()
console.log(user.$isPersisted) // false

await user.save()
console.log(user.$isPersisted) // true

$isNew

Opposite of the $isPersisted property.

$isLocal

Find if the model instance is created locally or fetched from the database.

const user = new User()
console.log(user.$isLocal) // true

await user.save()
console.log(user.$isLocal) // STILL true

In the following example, the model instance is created by fetching the row values from the database table.

const user = await User.find(1)
console.log(user.$isLocal) // false

$dirty

An object containing the diff between the $original and the $attributes object.

const user = await User.find(1)
user.points = 10

console.log(user.$dirty) // { points: 10 }

$isDirty

A boolean to know if the model is dirty.

const user = await User.find(1)
user.points = 10

console.log(user.$isDirty) // true

$isDeleted

Find if the model instance has been deleted or not. It is set to true after the delete method is invoked.

const user = await User.find(1)
console.log(user.$isDeleted) // false

await user.delete()
console.log(user.$isDeleted) // true

$trx

Reference to the transaction client used by the model instance. You can also set the $trx manually in order to perform model operations within the transaction block.

const trx = await Database.transaction()

const user = new User()
user.$trx = trx

await user.save()
await trx.commit()

console.log(user.$trx) // undefined

After transaction is committed or rolled back the model instance will release the $trx reference, so that the transaction client instance is garbage collected.

The $trx property on the model instance is automatically defined, when the model instances are created as a result of executing a query and the query was using the transaction.

const trx = await Database.transaction()

// select query is using trx
const users = await User.query().useTransaction(trx)

users.forEach((user) => {
  // all of the model instances uses the same trx instance
  console.log(user.$trx === trx) // true
})

$options

The $options is an object with an optional connection and the profiler property.

You can use the $options to define a custom connection per model instance. A practical use case is to use dynamic tenant connection per HTTP request.

const users = await User
  .query({ connection: tenant.connection })
  .select('*')

users.forEach((user) => {
  console.log(user.$options.connection === tenant.connection) // true
})

useTransaction

The useTransaction is an alternative to manually set the $trx property.

const trx = await Database.transaction()
const user = new User()

await user
  .useTransaction(trx)
  .save()

useConnection

The useConnection is an alternative to defining the $options with the connection property.

const user = new User()

await user
  .useConnection(tenant.connection)
  .save()

load

Load a relationship from a model instance.

const user = await User.findOrFail(1)
await user.load('posts')

console.log(user.posts)

You can also pass a callback as the second argument to add more constraints to the relationship query.

await user.load('posts', (postsQuery) => {
  postsQuery.where('status', 'published')
})

You can also load multiple relationships as follows:

await user.load((loader) => {
  loader.load('profile').load('posts')
})

The nested relations can be loaded as follows:

await user.load((loader) => {
  loader.load('profile', (profile) => {
    profile.preload('socialAccounts')
  }).load('posts')
})

related

Returns the relationship client instance for a given relationship. You can use the related method to run queries in reference to the defined relationship.

const user = await User.find(1)

const posts = await user.related('posts').query()
// select * from "posts" where "user_id" = user.id

Similarly, the related method can also be used to persist related rows.

const user = await User.find(1)

await user.related('posts').create({
  title: 'Adonis 101',
})

/**
INSERT INTO "posts"
  ("user_id", "title")
VALUES
  (user.id, 'Adonis 101')
*/

toObject

Returns an object with model $attributes, preloaded relationships and its computed properties.

console.log(user.toObject())

serialize

Serializes the model to its JSON representation. The serialization of models is helpful for building API servers.

Make sure to read the in-depth guide on models serialization .

console.log(user.serialize())

The serialize method also accepts an object for cherry-picking fields.

user.serialize({
  fields: {
    omit: ['password'],
  },
  relations: {
    profile: {
      fields: {
        pick: ['fullName', 'id'],
      },
    }
  }
})

The cherry picking argument can be a deeply nested tree targeting the relationships serialization as well.

toJSON

Alias for the serialize method but doesn't accept any arguments. The toJSON is called automatically anytime you pass model instance(s) to the JSON.stringify method.

serializeAttributes

Serializes just the model attributes.

user.serializeAttributes({
  omit: ['password']
})

serializeComputed

Serializes just the computed properties.

user.serializeComputed()

serializeRelations

Serializes just the preloaded relationships

user.serializeRelations()

// Cherry pick fields
user.serializeRelations({
  profile: {
    fields: {}
  },
  posts: {
    fields: {}
  }
})