sequelize/lib/deferrable.js

Sequelize is a promise-based Node.js ORM tool for Postgres, MySQL, MariaDB, SQLite, Microsoft SQL Server, Amazon Redshift and Snowflake’s Data Cloud. It features solid transaction support, relations, eager and lazy loading, read replication and more.

'use strict';

const { classToInvokable } = require('./utils');

class ABSTRACT {
  static toString(...args) {
    return new this().toString(...args);
  }

  toString(...args) {
    return this.toSql(...args);
  }

  toSql() {
    throw new Error('toSql implementation missing');
  }
}

class INITIALLY_DEFERRED extends ABSTRACT {
  toSql() {
    return 'DEFERRABLE INITIALLY DEFERRED';
  }
}

class INITIALLY_IMMEDIATE extends ABSTRACT {
  toSql() {
    return 'DEFERRABLE INITIALLY IMMEDIATE';
  }
}

class NOT extends ABSTRACT {
  toSql() {
    return 'NOT DEFERRABLE';
  }
}

class SET_DEFERRED extends ABSTRACT {
  constructor(constraints) {
    super();
    this.constraints = constraints;
  }

  toSql(queryGenerator) {
    return queryGenerator.setDeferredQuery(this.constraints);
  }
}

class SET_IMMEDIATE extends ABSTRACT {
  constructor(constraints) {
    super();
    this.constraints = constraints;
  }

  toSql(queryGenerator) {
    return queryGenerator.setImmediateQuery(this.constraints);
  }
}

/**
 * A collection of properties related to deferrable constraints. It can be used to
 * make foreign key constraints deferrable and to set the constraints within a
 * transaction. This is only supported in PostgreSQL.
 *
 * The foreign keys can be configured like this. It will create a foreign key
 * that will check the constraints immediately when the data was inserted.
 *
 * ```js
 * sequelize.define('Model', {
 *   foreign_id: {
 *     type: Sequelize.INTEGER,
 *     references: {
 *       model: OtherModel,
 *       key: 'id',
 *       deferrable: Sequelize.Deferrable.INITIALLY_IMMEDIATE
 *     }
 *   }
 * });
 * ```
 *
 * The constraints can be configured in a transaction like this. It will
 * trigger a query once the transaction has been started and set the constraints
 * to be checked at the very end of the transaction.
 *
 * ```js
 * sequelize.transaction({
 *   deferrable: Sequelize.Deferrable.SET_DEFERRED
 * });
 * ```
 *
 * @property INITIALLY_DEFERRED    Use when declaring a constraint. Allow and enable by default this constraint's checks to be deferred at the end of transactions.
 * @property INITIALLY_IMMEDIATE   Use when declaring a constraint. Allow the constraint's checks to be deferred at the end of transactions.
 * @property NOT                   Use when declaring a constraint. Set the constraint to not deferred. This is the default in PostgreSQL and makes it impossible to dynamically defer the constraints within a transaction.
 * @property SET_DEFERRED          Use when declaring a transaction. Defer the deferrable checks involved in this transaction at commit.
 * @property SET_IMMEDIATE         Use when declaring a transaction. Execute the deferrable checks involved in this transaction immediately.
 */

const Deferrable = {
  INITIALLY_DEFERRED: classToInvokable(INITIALLY_DEFERRED),
  INITIALLY_IMMEDIATE: classToInvokable(INITIALLY_IMMEDIATE),
  NOT: classToInvokable(NOT),
  SET_DEFERRED: classToInvokable(SET_DEFERRED),
  SET_IMMEDIATE: classToInvokable(SET_IMMEDIATE)
};

module.exports = Deferrable;