tachybase_todo/docs/en-US/api/database/collection.md

Collection

Overview

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

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

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

// Define 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'
    }
  ],
});

Refer to Fields for more field types.

Constructor

Signature

• constructor(options: CollectionOptions, context: CollectionContext)

Parameter

Name	Type	Default	Description
options.name	string	-	Identifier of the collection
options.tableName?	string	-	Database table name, the value of options.name is used if not set
options.fields?	FieldOptions[]	-	Definition of fields, refer to Field for details
options.model?	string | ModelStatic<Model>	-	Model type of Sequelize; in case string is used, this model name needs to be registered in the db before being called
options.repository?	string | RepositoryType	-	Data repository type; in case string is used, this repository type needs to be registered in the db before being called
options.sortable?	string | boolean | { name?: string; scopeKey?: string }	-	Configure which fields are sortable; not sortable by default
options.autoGenId?	boolean	true	Whether to automatically generate unique primary key; true by default
context.database	Database	-	The context database in which it resides

Example

Create a table posts:

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

Instance Member

options

Initial parameters for data table configuration, which are consistent with the options parameter of the constructor.

context

The contextual environment to which the current data table belongs, currently mainly the database instance.

name

Name of the data table.

db

The database instance to which it belongs.

filterTargetKey

Name of the field that is used as the primary key.

isThrough

Whether it is an intermediate table.

model

Match the Model type of Sequelize.

repository

Data repository instance.

Field Configuration Method

getField()

Get a field object whose corresponding name has been defined in the data table.

Signature

• getField(name: string): Field

Parameter

Name	Type	Default	Description
name	string	-	Name of the field

Example

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

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

setField()

Set a field to the data table.

Signature

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

Parameter

Name	Type	Default	Description
name	string	-	Name of the field
options	FieldOptions	-	Configuration of the field, refer to Field for details

Example

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

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

setFields()

Set multiple fields to the data table.

Signature

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

Parameter

Name	Type	Default	Description
fields	FieldOptions[]	-	Configuration of the fields, refer to Field for details
resetFields	boolean	true	Whether to reset existing fields

Example

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

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

removeField()

Remove a field object whose corresponding name has been defined in the data table.

Signature

• removeField(name: string): void | Field

Parameter

Name	Type	Default	Description
name	string	-	Name of the field

Example

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

posts.removeField('title');

resetFields()

Reset (Empty) fields of the data table.

Signature

• resetFields(): void

Example

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

posts.resetFields();

hasField()

Check if the data table has defined a field object with the corresponding name.

Signature

• hasField(name: string): boolean

Parameter

Name	Type	Default	Description
name	string	-	Name of the field

Example

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

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

findField()

Find field objects in the data table that match the conditions.

Signature

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

Parameter

Name	Type	Default	Description
predicate	(field: Field) => boolean	-	The condition

Example

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

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

forEachField()

Iterate over field objects in the data table.

Signature

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

Parameter

Name	Type	Default	Description
callback	(field: Field) => void	-	Callback function

Example

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

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

Index Configuration Method

addIndex()

Add data table index.

Signature

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

Parameter

Name	Type	Default	Description
index	string | string[]	-	Names of fields to be indexed
index	{ fields: string[], unique?: boolean, [key: string]: any }	-	Full configuration

Example

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

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

removeIndex()

Remove data table index.

Signature

• removeIndex(fields: string[])

Parameter

Name	Type	Default	Description
fields	string[]	-	Names of fields to remove indexes

Example

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

posts.removeIndex(['title']);

Table Configuration Method

remove()

Remove data table.

Signature

• remove(): void

Example

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

posts.remove();

Database Operation Method

sync()

Synchronize the definitions in data table to the database. In addition to the default Model.sync logic in Sequelize, the data tables corresponding to the relational fields will also be handled together.

Signature

• sync(): Promise<void>

Example

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

await posts.sync();

existsInDb()

Check whether the data table exists in the database.

Signature

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

Parameter

Name	Type	Default	Description
options?.transaction	Transaction	-	Transaction instance

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'
});

//  Synchronize the table books to the database
await db.sync();

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