#Collection

#Overview

Collection is used to define data models in the system, such as model names, fields, indexes, associations, and other information. It is generally called through the collection method of a Database instance as a proxy entry.

const { Database } = require('@nocobase/database')

// Create a database instance
const db = new Database({...});

// Define a data model
db.collection({
  name: 'users',
  // Define model fields
  fields: [
    // Scalar field
    {
      name: 'name',
      type: 'string',
    },

    // Association field
    {
      name: 'profile',
      type: 'hasOne' // 'hasMany', 'belongsTo', 'belongsToMany'
    }
  ],
});

For more field types, please refer to Fields.

#Constructor

Signature

• constructor(options: CollectionOptions, context: CollectionContext)

Parameters

Example

Create a posts collection:

const posts = new Collection(
  {
    name: 'posts',
    fields: [
      {
        type: 'string',
        name: 'title',
      },
      {
        type: 'double',
        name: 'price',
      },
    ],
  },
  {
    // Existing database instance
    database: db,
  },
);

#Instance Members

#options

Initial configuration parameters for the collection. Same as the options parameter of the constructor.

#context

The context to which the current collection belongs, currently mainly the database instance.

#name

Collection name.

#db

The database instance it belongs to.

#filterTargetKey

The field name used as the primary key.

#isThrough

Whether it is a through collection.

#model

Matches the Sequelize Model type.

#repository

Repository instance.

#Field Configuration Methods

#getField()

Gets the field object with the corresponding name defined in the collection.

Signature

• getField(name: string): Field

Parameters

Example

const posts = db.collection({
  name: 'posts',
  fields: [
    {
      type: 'string',
      name: 'title',
    },
  ],
});

const field = posts.getField('title');

#setField()

Sets a field for the collection.

Signature

• setField(name: string, options: FieldOptions): Field

Parameters

Example

const posts = db.collection({ name: 'posts' });

posts.setField('title', { type: 'string' });

#setFields()

Sets multiple fields for the collection in batch.

Signature

• setFields(fields: FieldOptions[], resetFields = true): Field[]

Parameters

Example

const posts = db.collection({ name: 'posts' });

posts.setFields([
  { type: 'string', name: 'title' },
  { type: 'double', name: 'price' },
]);

#removeField()

Removes the field object with the corresponding name defined in the collection.

Signature

• removeField(name: string): void | Field

Parameters

Example

const posts = db.collection({
  name: 'posts',
  fields: [
    {
      type: 'string',
      name: 'title',
    },
  ],
});

posts.removeField('title');

#resetFields()

Resets (clears) the fields of the collection.

Signature

• resetFields(): void

Example

const posts = db.collection({
  name: 'posts',
  fields: [
    {
      type: 'string',
      name: 'title',
    },
  ],
});

posts.resetFields();

#hasField()

Checks if a field object with the corresponding name is defined in the collection.

Signature

• hasField(name: string): boolean

Parameters

Example

const posts = db.collection({
  name: 'posts',
  fields: [
    {
      type: 'string',
      name: 'title',
    },
  ],
});

posts.hasField('title'); // true

#findField()

Finds a field object in the collection that meets the criteria.

Signature

• findField(predicate: (field: Field) => boolean): Field | undefined

Parameters

Example

const posts = db.collection({
  name: 'posts',
  fields: [
    {
      type: 'string',
      name: 'title',
    },
  ],
});

posts.findField((field) => field.name === 'title');

#forEachField()

Iterates over the field objects in the collection.

Signature

• forEachField(callback: (field: Field) => void): void

Parameters

Example

const posts = db.collection({
  name: 'posts',
  fields: [
    {
      type: 'string',
      name: 'title',
    },
  ],
});

posts.forEachField((field) => console.log(field.name));

#Index Configuration Methods

#addIndex()

Adds an index to the collection.

Signature

• addIndex(index: string | string[] | { fields: string[], unique?: boolean,[key: string]: any })

Parameters

Example

const posts = db.collection({
  name: 'posts',
  fields: [
    {
      type: 'string',
      name: 'title',
    },
  ],
});

posts.addIndex({
  fields: ['title'],
  unique: true,
});

#removeIndex()

Removes an index from the collection.

Signature

• removeIndex(fields: string[])

Parameters

Example

const posts = db.collection({
  name: 'posts',
  fields: [
    {
      type: 'string',
      name: 'title',
    },
  ],
  indexes: [
    {
      fields: ['title'],
      unique: true,
    },
  ],
});

posts.removeIndex(['title']);

#Collection Configuration Methods

#remove()

Deletes the collection.

Signature

• remove(): void

Example

const posts = db.collection({
  name: 'posts',
  fields: [
    {
      type: 'string',
      name: 'title',
    },
  ],
});

posts.remove();

#Database Operation Methods

#sync()

Syncs the collection definition to the database. In addition to the default logic of Model.sync in Sequelize, it also processes collections corresponding to association fields.

Signature

• sync(): Promise<void>

Example

const posts = db.collection({
  name: 'posts',
  fields: [
    {
      type: 'string',
      name: 'title',
    },
  ],
});

await posts.sync();

#existsInDb()

Checks if the collection exists in the database.

Signature

• existsInDb(options?: Transactionable): Promise<boolean>

Parameters

Example

const posts = db.collection({
  name: 'posts',
  fields: [
    {
      type: 'string',
      name: 'title',
    },
  ],
});

const existed = await posts.existsInDb();

console.log(existed); // false

#removeFromDb()

Signature

• removeFromDb(): Promise<void>

Example

const books = db.collection({
  name: 'books',
});

// Sync the books collection to the database
await db.sync();

// Remove the books collection from the database
await books.removeFromDb();