loopback-datasource-juggler/lib/dao.js

LoopBack DataSource Juggler

// Copyright IBM Corp. 2013,2020. All Rights Reserved.
// Node module: loopback-datasource-juggler
// This file is licensed under the MIT License.
// License text available at https://opensource.org/licenses/MIT

// Turning on strict for this file breaks lots of test cases;
// disabling strict for this file
/* eslint-disable strict */

/*!
 * Module exports class Model
 */
module.exports = DataAccessObject;

/*!
 * Module dependencies
 */
const g = require('strong-globalize')();
const async = require('async');
const jutil = require('./jutil');
const DataAccessObjectUtils = require('./model-utils');
const ValidationError = require('./validations').ValidationError;
const Relation = require('./relations.js');
const Inclusion = require('./include.js');
const List = require('./list.js');
const geo = require('./geo');
const Memory = require('./connectors/memory').Memory;
const utils = require('./utils');
const fieldsToArray = utils.fieldsToArray;
const sanitizeQueryOrData = utils.sanitizeQuery;
const setScopeValuesFromWhere = utils.setScopeValuesFromWhere;
const idEquals = utils.idEquals;
const mergeQuery = utils.mergeQuery;
const assert = require('assert');
const BaseModel = require('./model');
const debug = require('debug')('loopback:dao');

/**
 * Base class for all persistent objects.
 * Provides a common API to access any database connector.
 * This class describes only abstract behavior.  Refer to the specific connector for additional details.
 *
 * `DataAccessObject` mixes `Inclusion` classes methods.
 * @class DataAccessObject
 */
function DataAccessObject() {
  if (DataAccessObject._mixins) {
    const self = this;
    const args = arguments;
    DataAccessObject._mixins.forEach(function(m) {
      m.call(self, args);
    });
  }
}

function idName(m) {
  return m.definition.idName() || 'id';
}

function getIdValue(m, data) {
  return data && data[idName(m)];
}

function copyData(from, to) {
  for (const key in from) {
    to[key] = from[key];
  }
}

function convertSubsetOfPropertiesByType(inst, data) {
  const typedData = {};
  for (const key in data) {
    // Convert the properties by type
    typedData[key] = inst[key];
    if (typeof typedData[key] === 'object' &&
            typedData[key] !== null &&
            typeof typedData[key].toObject === 'function') {
      typedData[key] = typedData[key].toObject();
    }
  }
  return typedData;
}

/**
 * Apply strict check for model's data.
 * Notice: Please note this method modifies `inst` when `strict` is `validate`.
 */
function applyStrictCheck(model, strict, data, inst, cb) {
  const props = model.definition.properties;
  const keys = Object.keys(data);
  const result = {};
  for (let i = 0; i < keys.length; i++) {
    const key = keys[i];
    if (props[key]) {
      result[key] = data[key];
    } else if (strict && strict !== 'filter') {
      inst.__unknownProperties.push(key);
    }
  }
  cb(null, result);
}

function setIdValue(m, data, value) {
  if (data) {
    data[idName(m)] = value;
  }
}

function byIdQuery(m, id) {
  const pk = idName(m);
  const query = {where: {}};
  query.where[pk] = id;
  return query;
}

function isWhereByGivenId(Model, where, idValue) {
  const keys = Object.keys(where);
  if (keys.length != 1) return false;

  const pk = idName(Model);
  if (keys[0] !== pk) return false;

  return where[pk] === idValue;
}

function errorModelNotFound(idValue) {
  const msg = g.f('Could not update attributes. {{Object}} with {{id}} %s does not exist!', idValue);
  const error = new Error(msg);
  error.statusCode = error.status = 404;
  return error;
}

function invokeConnectorMethod(connector, method, Model, args, options, cb) {
  const dataSource = Model.getDataSource();
  // If the DataSource is a transaction and no transaction object is provide in
  // the options yet, add it to the options, see: DataSource#transaction()
  const opts = dataSource.isTransaction && !options.transaction ? Object.assign(
    options, {transaction: dataSource.currentTransaction},
  ) : options;
  const optionsSupported = connector[method].length >= args.length + 3;
  const transaction = opts.transaction;
  if (transaction) {
    if (!optionsSupported) {
      return process.nextTick(function() {
        cb(new Error(g.f(
          'The connector does not support {{method}} within a transaction', method,
        )));
      });
    }
    // transaction isn't always a Transaction instance. Some tests provide a
    // string to test if options get passed through, so check for ensureActive:
    if (transaction.ensureActive && !transaction.ensureActive(cb)) {
      return;
    }
  }
  const modelName = Model.modelName;
  let fullArgs;
  if (!optionsSupported && method === 'count') {
    // NOTE: The old count() signature is irregular, with `where` coming last:
    // [modelName, cb, where]
    const where = args[0];
    fullArgs = [modelName, cb, where];
  } else {
    // Standard signature: [modelName, ...args, (opts, ) cb]
    fullArgs = [modelName].concat(args);
    if (optionsSupported) {
      fullArgs.push(opts);
    }
    fullArgs.push(cb);
  }
  connector[method].apply(connector, fullArgs);
}

DataAccessObject._forDB = function(data) {
  if (!(this.getDataSource().isRelational && this.getDataSource().isRelational())) {
    return data;
  }
  const res = {};
  for (const propName in data) {
    const type = this.getPropertyType(propName);
    const value = data[propName];
    if (value !== null && (type === 'JSON' || type === 'Any' ||
        type === 'Object' || value instanceof Array)) {
      res[propName] = JSON.stringify(value);
    } else {
      res[propName] = value;
    }
  }
  return res;
};

DataAccessObject.defaultScope = function(target, inst) {
  let scope = this.definition.settings.scope;
  if (typeof scope === 'function') {
    scope = this.definition.settings.scope.call(this, target, inst);
  }
  return scope;
};

DataAccessObject.applyScope = function(query, inst) {
  const scope = this.defaultScope(query, inst) || {};
  if (typeof scope === 'object') {
    mergeQuery(query, scope || {}, this.definition.settings.scope);
  }
};

DataAccessObject.applyProperties = function(data, inst) {
  let properties = this.definition.settings.properties;
  properties = properties || this.definition.settings.attributes;
  if (typeof properties === 'object') {
    Object.assign(data, properties);
  } else if (typeof properties === 'function') {
    Object.assign(data, properties.call(this, data, inst) || {});
  } else if (properties !== false) {
    const scope = this.defaultScope(data, inst) || {};
    if (typeof scope.where === 'object') {
      setScopeValuesFromWhere(data, scope.where, this);
    }
  }
};

DataAccessObject.lookupModel = function(data) {
  return this;
};

/**
 * Get the connector instance for the given model class
 * @returns {Connector} The connector instance
 */
DataAccessObject.getConnector = function() {
  return this.getDataSource().connector;
};

/**
 * Create an instance of Model with given data and save to the attached data source. Callback is optional.
 * Example:
 *```js
 * User.create({first: 'Joe', last: 'Bob'}, function(err, user) {
 *  console.log(user instanceof User); // true
 * });
 * ```
 * Note: You must include a callback and use the created model provided in the callback if your code depends on your model being
 * saved or having an ID.
 *
 * @param {Object} [data] Optional data object
 * @param {Object} [options] Options for create
 * @param {Function} [cb]  Callback function called with these arguments:
 *   - err (null or Error)
 *   - instance (null or Model)
 */
DataAccessObject.create = function(data, options, cb) {
  const connectionPromise = stillConnecting(this.getDataSource(), this, arguments);
  if (connectionPromise) {
    return connectionPromise;
  }

  let Model = this;
  const connector = Model.getConnector();
  assert(typeof connector.create === 'function',
    'create() must be implemented by the connector');

  const self = this;

  if (options === undefined && cb === undefined) {
    if (typeof data === 'function') {
      // create(cb)
      cb = data;
      data = {};
    }
  } else if (cb === undefined) {
    if (typeof options === 'function') {
      // create(data, cb);
      cb = options;
      options = {};
    }
  }

  data = data || {};
  options = options || {};
  cb = cb || utils.createPromiseCallback();

  assert(typeof data === 'object', 'The data argument must be an object or array');
  assert(typeof options === 'object', 'The options argument must be an object');
  assert(typeof cb === 'function', 'The cb argument must be a function');

  const hookState = {};

  if (Array.isArray(data)) {
    // Undefined item will be skipped by async.map() which internally uses
    // Array.prototype.map(). The following loop makes sure all items are
    // iterated
    for (let i = 0, n = data.length; i < n; i++) {
      if (data[i] === undefined) {
        data[i] = {};
      }
    }
    async.map(data, function(item, done) {
      self.create(item, options, function(err, result) {
        // Collect all errors and results
        done(null, {err: err, result: result || item});
      });
    }, function(err, results) {
      if (err) {
        return cb(err, results);
      }
      // Convert the results into two arrays
      let errors = null;
      const data = [];
      for (let i = 0, n = results.length; i < n; i++) {
        if (results[i].err) {
          if (!errors) {
            errors = [];
          }
          errors[i] = results[i].err;
        }
        data[i] = results[i].result;
      }
      cb(errors, data);
    });
    return cb.promise;
  }

  const enforced = {};
  let obj;
  const idValue = getIdValue(this, data);

  try {
  // if we come from save
    if (data instanceof Model && !idValue) {
      obj = data;
    } else {
      obj = new Model(data);
    }

    this.applyProperties(enforced, obj);
    obj.setAttributes(enforced);
  } catch (err) {
    process.nextTick(function() {
      cb(err);
    });
    return cb.promise;
  }

  Model = this.lookupModel(data); // data-specific
  if (Model !== obj.constructor) obj = new Model(data);

  let context = {
    Model: Model,
    instance: obj,
    isNewInstance: true,
    hookState: hookState,
    options: options,
  };
  Model.notifyObserversOf('before save', context, function(err) {
    if (err) return cb(err);

    data = obj.toObject(true);

    // options has precedence on model-setting
    if (options.validate === false) {
      return create();
    }

    // only when options.validate is not set, take model-setting into consideration
    if (options.validate === undefined && Model.settings.automaticValidation === false) {
      return create();
    }

    // validation required
    obj.isValid(function(valid) {
      if (valid) {
        create();
      } else {
        cb(new ValidationError(obj), obj);
      }
    }, data, options);
  });

  function create() {
    obj.trigger('create', function(createDone) {
      obj.trigger('save', function(saveDone) {
        const _idName = idName(Model);
        let val = Model._sanitizeData(obj.toObject(true), options);
        function createCallback(err, id, rev) {
          if (id) {
            obj.__data[_idName] = id;
            defineReadonlyProp(obj, _idName, id);
          }
          if (rev) {
            obj._rev = rev;
          }
          if (err) {
            return cb(err, obj);
          }
          obj.__persisted = true;

          const context = {
            Model: Model,
            data: val,
            isNewInstance: true,
            hookState: hookState,
            options: options,
          };
          Model.notifyObserversOf('loaded', context, function(err) {
            if (err) return cb(err);

            // By default, the instance passed to create callback is NOT updated
            // with the changes made through persist/loaded hooks. To preserve
            // backwards compatibility, we introduced a new setting updateOnLoad,
            // which if set, will apply these changes to the model instance too.
            if (Model.settings.updateOnLoad) {
              obj.setAttributes(context.data);
            }
            saveDone.call(obj, function() {
              createDone.call(obj, function() {
                if (err) {
                  return cb(err, obj);
                }
                const context = {
                  Model: Model,
                  instance: obj,
                  isNewInstance: true,
                  hookState: hookState,
                  options: options,
                };
                if (options.notify !== false) {
                  Model.notifyObserversOf('after save', context, function(err) {
                    cb(err, obj);
                  });
                } else {
                  cb(null, obj);
                }
              });
            });
          });
        }

        val = applyDefaultsOnWrites(val, Model.definition);

        context = {
          Model: Model,
          data: val,
          isNewInstance: true,
          currentInstance: obj,
          hookState: hookState,
          options: options,
        };
        Model.notifyObserversOf('persist', context, function(err, ctx) {
          if (err) return cb(err);
          val = ctx.data;
          invokeConnectorMethod(connector, 'create', Model, [obj.constructor._forDB(ctx.data)],
            options, createCallback);
        });
      }, obj, cb);
    }, obj, cb);
  }

  return cb.promise;
};

/**
 * Create an instances of Model with given data array and save to the attached data source. Callback is optional.
 * Example:
 *```js
 * User.createAll([{first: 'Joe', last: 'Bob'},{first: 'Tom', last: 'Cat'}], function(err, users) {
 *  console.log(users[0] instanceof User); // true
 * });
 * ```
 * Note: You must include a callback and use the created models provided in the callback if your code depends on your model being
 * saved or having an ID.
 *
 * @param {Object} [dataArray] Optional data object with array of records
 * @param {Object} [options] Options for create
 * @param {Function} [cb]  Callback function called with these arguments:
 *   - err (null or Error)
 *   - instance (null or Models)
 */
DataAccessObject.createAll = function(dataArray, options, cb) {
  const connectionPromise = stillConnecting(this.getDataSource(), this, arguments);
  if (connectionPromise) {
    return connectionPromise;
  }

  let Model = this;
  const connector = Model.getConnector();
  if (!connector.multiInsertSupported) {
    // If multi insert is not supported, then, revert to create method
    // Array is handled in create method already in legacy code
    // This ensures backwards compatibility
    return this.create(dataArray, options, cb);
  }
  assert(
    typeof connector.createAll === 'function',
    'createAll() must be implemented by the connector',
  );

  if (options === undefined && cb === undefined) {
    if (typeof dataArray === 'function') {
      // create(cb)
      cb = dataArray;
      dataArray = [];
    }
  } else if (cb === undefined) {
    if (typeof options === 'function') {
      // create(data, cb);
      cb = options;
      options = {};
    }
  }

  dataArray = dataArray || [];
  options = options || {};
  cb = cb || utils.createPromiseCallback();

  assert(typeof dataArray === 'object' && dataArray.length,
    'The data argument must be an array with length > 0');
  assert(typeof options === 'object', 'The options argument must be an object');
  assert(typeof cb === 'function', 'The cb argument must be a function');

  const validationPromises = [];
  for (let index = 0; index < dataArray.length; index++) {
    const data = dataArray[index];
    const hookState = {};

    const enforced = {};
    let obj;

    try {
      obj = new Model(data);

      this.applyProperties(enforced, obj);
      obj.setAttributes(enforced);
    } catch (err) {
      process.nextTick(function() {
        cb(err);
      });
      return cb.promise;
    }

    Model = this.lookupModel(data); // data-specific
    if (Model !== obj.constructor) obj = new Model(data);

    const context = {
      Model: Model,
      instance: obj,
      isNewInstance: true,
      hookState: hookState,
      options: options,
    };

    const promise = new Promise((resolve, reject) => {
      Model.notifyObserversOf('before save', context, function(err) {
        if (err) return reject({
          error: err,
          data: obj,
        });

        const d = obj.toObject(true);

        // options has precedence on model-setting
        if (options.validate === false) {
          return resolve(obj);
        }

        // only when options.validate is not set, take model-setting into consideration
        if (
          options.validate === undefined &&
        Model.settings.automaticValidation === false
        ) {
          return resolve(obj);
        }

        // validation required
        obj.isValid(
          function(valid) {
            if (valid) {
              resolve(obj);
            } else {
              reject({
                error: new ValidationError(obj),
                data: obj,
              });
            }
          },
          d,
          options,
        );
      });
    });
    validationPromises.push(promise);
  }

  Promise.all(validationPromises).then((objArray) => {
    const values = [];
    const valMap = new Map();
    objArray.forEach((obj) => {
      const val = Model._sanitizeData(obj.toObject(true), options);
      values.push(val);
      valMap.set(obj, applyDefaultsOnWrites(val, Model.definition));
    });

    const _idName = idName(Model);

    function createCallback(err, savedArray) {
      if (err) {
        return cb(err, objArray);
      }
      const contextArr = savedArray.map((obj, i) => {
        return {
          Model: Model,
          data: obj,
          isNewInstance: true,
          hookState: context[i].hookState,
          options: context[i].options,
        };
      });
      Model.notifyObserversOf('loaded', contextArr, function(err) {
        if (err) return cb(err);

        const afterSavePromises = [];
        savedArray.map((obj, i) => {
          const dataModel = context[i].currentInstance;
          const id = obj[_idName];
          if (id) {
            dataModel.__data[_idName] = id;
            defineReadonlyProp(dataModel, _idName, id);
          }
          dataModel.__persisted = true;

          // By default, the instance passed to create callback is NOT updated
          // with the changes made through persist/loaded hooks. To preserve
          // backwards compatibility, we introduced a new setting updateOnLoad,
          // which if set, will apply these changes to the model instance too.
          if (Model.settings.updateOnLoad) {
            dataModel.setAttributes(obj);
          }

          const contxt = {
            Model: Model,
            instance: dataModel,
            isNewInstance: true,
            hookState: context[i].hookState,
            options: context[i].options,
          };

          let afterSavePromise;
          if (options.notify !== false) {
            afterSavePromise = new Promise((resolve, reject) => {
              Model.notifyObserversOf('after save', contxt, function(err) {
                if (err) {
                  reject(err);
                } else {
                  resolve(dataModel);
                }
              });
            });
            afterSavePromises.push(afterSavePromise);
          } else {
            afterSavePromises.push(Promise.resolve(dataModel));
          }
        });

        Promise.all(afterSavePromises)
          .then((saved) => {
            cb(null, saved);
          })
          .catch((err) => {
            cb(err, objArray);
          });
      });
    }

    const context = objArray.map(obj => {
      return {
        Model: Model,
        data: valMap.get(obj),
        isNewInstance: true,
        currentInstance: obj,
        hookState: {},
        options: options,
      };
    });
    const persistPromise = new Promise((resolve, reject) => {
      Model.notifyObserversOf('persist', context, function(err, ctx) {
        if (err) return reject(err);

        const objDataArray = ctx
          .map((obj) => {
            return obj.currentInstance.constructor._forDB(obj.data);
          })
          .filter((objData) => !!objData);
        resolve(objDataArray);
      });
    });
    persistPromise.then((objDataArray) => {
      invokeConnectorMethod(
        connector,
        'createAll',
        Model,
        [objDataArray],
        options,
        createCallback,
      );
    }).catch((err) => {
      err && cb(err);
    });
  }).catch((err) => {
    err && cb(err.error, err.data);
  });

  return cb.promise;
};

// Implementation of applyDefaultOnWrites property
function applyDefaultsOnWrites(obj, modelDefinition) {
  for (const key in modelDefinition.properties) {
    const prop = modelDefinition.properties[key];
    if ('applyDefaultOnWrites' in prop && !prop.applyDefaultOnWrites &&
      prop.default !== undefined && prop.default === obj[key]) {
      delete obj[key];
    }
  }

  return obj;
}

function stillConnecting(dataSource, obj, args) {
  if (typeof args[args.length - 1] === 'function') {
    return dataSource.ready(obj, args);
  }

  // promise variant
  const promiseArgs = Array.prototype.slice.call(args);
  promiseArgs.callee = args.callee;
  const cb = utils.createPromiseCallback();
  promiseArgs.push(cb);
  if (dataSource.ready(obj, promiseArgs)) {
    return cb.promise;
  } else {
    return false;
  }
}

/**
 * Update or insert a model instance: update exiting record if one is found, such that parameter `data.id` matches `id` of model instance;
 * otherwise, insert a new record.
 *
 * NOTE: No setters, validations, or hooks are applied when using upsert.
 * `updateOrCreate` and `patchOrCreate` are aliases
 * @param {Object} data The model instance data
 * @param {Object} [options] Options for upsert
 * @param {Function} cb The callback function (optional).
 */
// [FIXME] rfeng: This is a hack to set up 'upsert' first so that
// 'upsert' will be used as the name for strong-remoting to keep it backward
// compatible for angular SDK
DataAccessObject.updateOrCreate =
DataAccessObject.patchOrCreate =
DataAccessObject.upsert = function(data, options, cb) {
  const connectionPromise = stillConnecting(this.getDataSource(), this, arguments);
  if (connectionPromise) {
    return connectionPromise;
  }

  if (options === undefined && cb === undefined) {
    if (typeof data === 'function') {
      // upsert(cb)
      cb = data;
      data = {};
    }
  } else if (cb === undefined) {
    if (typeof options === 'function') {
      // upsert(data, cb)
      cb = options;
      options = {};
    }
  }

  cb = cb || utils.createPromiseCallback();
  data = data || {};
  options = options || {};

  assert(typeof data === 'object', 'The data argument must be an object');
  assert(typeof options === 'object', 'The options argument must be an object');
  assert(typeof cb === 'function', 'The cb argument must be a function');

  if (Array.isArray(data)) {
    cb(new Error('updateOrCreate does not support bulk mode or any array input'));
    return cb.promise;
  }

  const hookState = {};

  const self = this;
  let Model = this;
  const connector = Model.getConnector();

  const id = getIdValue(this, data);
  if (id === undefined || id === null) {
    return this.create(data, options, cb);
  }
  let doValidate = undefined;
  if (options.validate === undefined) {
    if (Model.settings.validateUpsert === undefined) {
      if (Model.settings.automaticValidation !== undefined) {
        doValidate = Model.settings.automaticValidation;
      }
    } else {
      doValidate = Model.settings.validateUpsert;
    }
  } else {
    doValidate = options.validate;
  }

  const forceId = this.settings.forceId;
  if (forceId) {
    options = Object.create(options);
    options.validate = !!doValidate;
    Model.findById(id, options, function(err, model) {
      if (err) return cb(err);
      if (!model) return cb(errorModelNotFound(id));
      model.updateAttributes(data, options, cb);
    });
    return cb.promise;
  }

  const context = {
    Model: Model,
    query: byIdQuery(Model, id),
    hookState: hookState,
    options: options,
  };
  Model.notifyObserversOf('access', context, doUpdateOrCreate);

  function doUpdateOrCreate(err, ctx) {
    if (err) return cb(err);

    const isOriginalQuery = isWhereByGivenId(Model, ctx.query.where, id);
    if (connector.updateOrCreate && isOriginalQuery) {
      let context = {
        Model: Model,
        where: ctx.query.where,
        data: data,
        hookState: hookState,
        options: options,
      };
      Model.notifyObserversOf('before save', context, function(err, ctx) {
        if (err) return cb(err);

        data = ctx.data;
        let update = data;
        let inst = data;
        if (!(data instanceof Model)) {
          inst = new Model(data, {applyDefaultValues: false});
        }
        update = inst.toObject(false);

        Model.applyProperties(update, inst);
        Model = Model.lookupModel(update);

        if (doValidate === false) {
          callConnector();
        } else {
          inst.isValid(function(valid) {
            if (!valid) {
              if (doValidate) { // backwards compatibility with validateUpsert:undefined
                return cb(new ValidationError(inst), inst);
              } else {
                // TODO(bajtos) Remove validateUpsert:undefined in v3.0
                g.warn('Ignoring validation errors in {{updateOrCreate()}}:');
                g.warn('  %s', new ValidationError(inst).message);
                // continue with updateOrCreate
              }
            }
            callConnector();
          }, update, options);
        }

        function callConnector() {
          update = Model._sanitizeData(update, options);
          context = {
            Model: Model,
            where: ctx.where,
            data: update,
            currentInstance: inst,
            hookState: ctx.hookState,
            options: options,
          };
          Model.notifyObserversOf('persist', context, function(err) {
            if (err) return done(err);
            invokeConnectorMethod(connector, 'updateOrCreate', Model, [update], options, done);
          });
        }
        function done(err, data, info) {
          if (err) return cb(err);
          const context = {
            Model: Model,
            data: data,
            isNewInstance: info && info.isNewInstance,
            hookState: ctx.hookState,
            options: options,
          };
          Model.notifyObserversOf('loaded', context, function(err) {
            if (err) return cb(err);

            let obj;
            if (data && !(data instanceof Model)) {
              inst._initProperties(data, {persisted: true});
              obj = inst;
            } else {
              obj = data;
            }
            if (err) {
              cb(err, obj);
            } else {
              const context = {
                Model: Model,
                instance: obj,
                isNewInstance: info ? info.isNewInstance : undefined,
                hookState: hookState,
                options: options,
              };

              if (options.notify !== false) {
                Model.notifyObserversOf('after save', context, function(err) {
                  cb(err, obj);
                });
              } else {
                cb(null, obj);
              }
            }
          });
        }
      });
    } else {
      const opts = {notify: false};
      if (ctx.options && ctx.options.transaction) {
        opts.transaction = ctx.options.transaction;
      }
      Model.findOne({where: ctx.query.where}, opts, function(err, inst) {
        if (err) {
          return cb(err);
        }
        if (!isOriginalQuery) {
          // The custom query returned from a hook may hide the fact that
          // there is already a model with `id` value `data[idName(Model)]`
          delete data[idName(Model)];
        }
        if (inst) {
          inst.updateAttributes(data, options, cb);
        } else {
          Model = self.lookupModel(data);
          const obj = new Model(data);
          obj.save(options, cb);
        }
      });
    }
  }
  return cb.promise;
};
/**
 * Update or insert a model instance based on the search criteria.
 * If there is a single instance retrieved, update the retrieved model.
 * Creates a new model if no model instances were found.
 * Returns an error if multiple instances are found.
 * @param {Object} [where]  `where` filter, like
 * ```
 * { key: val, key2: {gt: 'val2'}, ...}
 * ```
 * <br/>see
 * [Where filter](https://docs.strongloop.com/display/LB/Where+filter#Wherefilter-Whereclauseforothermethods).
 * @param {Object} data The model instance data to insert.
 * @callback {Function} callback Callback function called with `cb(err, obj)` signature.
 * @param {Error} err Error object; see [Error object](http://docs.strongloop.com/display/LB/Error+object).
 * @param {Object} model Updated model instance.
 */
DataAccessObject.patchOrCreateWithWhere =
DataAccessObject.upsertWithWhere = function(where, data, options, cb) {
  const connectionPromise = stillConnecting(this.getDataSource(), this, arguments);
  if (connectionPromise) { return connectionPromise; }
  if (cb === undefined) {
    if (typeof options === 'function') {
      // upsertWithWhere(where, data, cb)
      cb = options;
      options = {};
    }
  }
  cb = cb || utils.createPromiseCallback();
  options = options || {};
  assert(typeof where === 'object', 'The where argument must be an object');
  assert(typeof data === 'object', 'The data argument must be an object');
  assert(typeof options === 'object', 'The options argument must be an object');
  assert(typeof cb === 'function', 'The cb argument must be a function');
  if (Object.keys(data).length === 0) {
    const err = new Error('data object cannot be empty!');
    err.statusCode = 400;
    process.nextTick(function() { cb(err); });
    return cb.promise;
  }
  const hookState = {};
  const self = this;
  let Model = this;
  const connector = Model.getConnector();
  const query = {where: where};
  const context = {
    Model: Model,
    query: query,
    hookState: hookState,
    options: options,
  };
  Model.notifyObserversOf('access', context, doUpsertWithWhere);
  function doUpsertWithWhere(err, ctx) {
    if (err) return cb(err);
    ctx.data = data;
    if (connector.upsertWithWhere) {
      let context = {
        Model: Model,
        where: ctx.query.where,
        data: ctx.data,
        hookState: hookState,
        options: options,
      };
      Model.notifyObserversOf('before save', context, function(err, ctx) {
        if (err) return cb(err);
        data = ctx.data;
        let update = data;
        let inst = data;
        if (!(data instanceof Model)) {
          inst = new Model(data, {applyDefaultValues: false});
        }
        update = inst.toObject(false);
        Model.applyScope(query);
        Model.applyProperties(update, inst);
        Model = Model.lookupModel(update);
        if (options.validate === false) {
          return callConnector();
        }
        if (options.validate === undefined && Model.settings.automaticValidation === false) {
          return callConnector();
        }
        inst.isValid(function(valid) {
          if (!valid) return cb(new ValidationError(inst), inst);
          callConnector();
        }, update, options);

        function callConnector() {
          try {
            ctx.where = Model._sanitizeQuery(ctx.where, options);
            ctx.where = Model._coerce(ctx.where, options);
            update = Model._sanitizeData(update, options);
            update = Model._coerce(update, options);
          } catch (err) {
            return process.nextTick(function() {
              cb(err);
            });
          }
          context = {
            Model: Model,
            where: ctx.where,
            data: update,
            currentInstance: inst,
            hookState: ctx.hookState,
            options: options,
          };
          Model.notifyObserversOf('persist', context, function(err) {
            if (err) return done(err);
            invokeConnectorMethod(connector, 'upsertWithWhere', Model, [ctx.where, update], options, done);
          });
        }
        function done(err, data, info) {
          if (err) return cb(err);
          const contxt = {
            Model: Model,
            data: data,
            isNewInstance: info && info.isNewInstance,
            hookState: ctx.hookState,
            options: options,
          };
          Model.notifyObserversOf('loaded', contxt, function(err) {
            if (err) return cb(err);
            let obj;
            if (contxt.data && !(contxt.data instanceof Model)) {
              inst._initProperties(contxt.data, {persisted: true});
              obj = inst;
            } else {
              obj = contxt.data;
            }
            const context = {
              Model: Model,
              instance: obj,
              isNewInstance: info ? info.isNewInstance : undefined,
              hookState: hookState,
              options: options,
            };
            Model.notifyObserversOf('after save', context, function(err) {
              cb(err, obj);
            });
          });
        }
      });
    } else {
      const opts = {notify: false};
      if (ctx.options && ctx.options.transaction) {
        opts.transaction = ctx.options.transaction;
      }
      self.find({where: ctx.query.where}, opts, function(err, instances) {
        if (err) return cb(err);
        const modelsLength = instances.length;
        if (modelsLength === 0) {
          self.create(data, options, cb);
        } else if (modelsLength === 1) {
          const modelInst = instances[0];
          modelInst.updateAttributes(data, options, cb);
        } else {
          process.nextTick(function() {
            const error = new Error('There are multiple instances found.' +
                'Upsert Operation will not be performed!');
            error.statusCode = 400;
            cb(error);
          });
        }
      });
    }
  }
  return cb.promise;
};
/**
 * Replace or insert a model instance: replace exiting record if one is found, such that parameter `data.id` matches `id` of model instance;
 * otherwise, insert a new record.
 *
 * @param {Object} data The model instance data
 * @param {Object} [options] Options for replaceOrCreate
 * @param {Function} cb The callback function (optional).
 */

DataAccessObject.replaceOrCreate = function replaceOrCreate(data, options, cb) {
  const connectionPromise = stillConnecting(this.getDataSource(), this, arguments);
  if (connectionPromise) {
    return connectionPromise;
  }

  if (cb === undefined) {
    if (typeof options === 'function') {
      // replaceOrCreta(data,cb)
      cb = options;
      options = {};
    }
  }

  cb = cb || utils.createPromiseCallback();
  data = data || {};
  options = options || {};

  assert(typeof data === 'object', 'The data argument must be an object');
  assert(typeof options === 'object', 'The options argument must be an object');
  assert(typeof cb === 'function', 'The cb argument must be a function');

  const hookState = {};

  const self = this;
  let Model = this;
  const connector = Model.getConnector();

  let id = getIdValue(this, data);
  if (id === undefined || id === null) {
    return this.create(data, options, cb);
  }

  const forceId = this.settings.forceId;
  if (forceId) {
    return Model.replaceById(id, data, options, cb);
  }

  let inst;
  if (data instanceof Model) {
    inst = data;
  } else {
    inst = new Model(data);
  }

  const strict = inst.__strict;
  const context = {
    Model: Model,
    query: byIdQuery(Model, id),
    hookState: hookState,
    options: options,
  };
  Model.notifyObserversOf('access', context, doReplaceOrCreate);

  function doReplaceOrCreate(err, ctx) {
    if (err) return cb(err);

    const isOriginalQuery = isWhereByGivenId(Model, ctx.query.where, id);
    const where = ctx.query.where;
    if (connector.replaceOrCreate && isOriginalQuery) {
      let context = {
        Model: Model,
        instance: inst,
        hookState: hookState,
        options: options,
      };
      Model.notifyObserversOf('before save', context, function(err, ctx) {
        if (err) return cb(err);
        let update = inst.toObject(false);
        if (strict) {
          applyStrictCheck(Model, strict, update, inst, validateAndCallConnector);
        } else {
          validateAndCallConnector();
        }

        function validateAndCallConnector(err) {
          if (err) return cb(err);
          Model.applyProperties(update, inst);
          Model = Model.lookupModel(update);

          if (options.validate === false) {
            return callConnector();
          }

          // only when options.validate is not set, take model-setting into consideration
          if (options.validate === undefined && Model.settings.automaticValidation === false) {
            return callConnector();
          }

          inst.isValid(function(valid) {
            if (!valid) return cb(new ValidationError(inst), inst);
            callConnector();
          }, update, options);

          function callConnector() {
            update = Model._sanitizeData(update, options);
            context = {
              Model: Model,
              where: where,
              data: update,
              currentInstance: inst,
              hookState: ctx.hookState,
              options: options,
            };
            Model.notifyObserversOf('persist', context, function(err) {
              if (err) return done(err);
              invokeConnectorMethod(connector, 'replaceOrCreate', Model, [context.data], options, done);
            });
          }
          function done(err, data, info) {
            if (err) return cb(err);
            const context = {
              Model: Model,
              data: data,
              isNewInstance: info ? info.isNewInstance : undefined,
              hookState: ctx.hookState,
              options: options,
            };
            Model.notifyObserversOf('loaded', context, function(err) {
              if (err) return cb(err);

              let obj;
              if (data && !(data instanceof Model)) {
                inst._initProperties(data, {persisted: true});
                obj = inst;
              } else {
                obj = data;
              }
              if (err) {
                cb(err, obj);
              } else {
                const context = {
                  Model: Model,
                  instance: obj,
                  isNewInstance: info ? info.isNewInstance : undefined,
                  hookState: hookState,
                  options: options,
                };

                Model.notifyObserversOf('after save', context, function(err) {
                  cb(err, obj, info);
                });
              }
            });
          }
        }
      });
    } else {
      const opts = {notify: false};
      if (ctx.options && ctx.options.transaction) {
        opts.transaction = ctx.options.transaction;
      }
      Model.findOne({where: ctx.query.where}, opts, function(err, found) {
        if (err) return cb(err);
        if (!isOriginalQuery) {
          // The custom query returned from a hook may hide the fact that
          // there is already a model with `id` value `data[idName(Model)]`
          const pkName = idName(Model);
          delete data[pkName];
          if (found) id = found[pkName];
        }
        if (found) {
          self.replaceById(id, data, options, cb);
        } else {
          Model = self.lookupModel(data);
          const obj = new Model(data);
          obj.save(options, cb);
        }
      });
    }
  }
  return cb.promise;
};

/**
 * Find one record that matches specified query criteria.  Same as `find`, but limited to one record, and this function returns an
 * object, not a collection.
 * If the specified instance is not found, then create it using data provided as second argument.
 *
 * @param {Object} query Search conditions. See [find](#dataaccessobjectfindquery-callback) for query format.
 * For example: `{where: {test: 'me'}}`.
 * @param {Object} data Object to create.
 * @param {Object} [options] Option for findOrCreate
 * @param {Function} cb Callback called with (err, instance, created)
 */
DataAccessObject.findOrCreate = function findOrCreate(query, data, options, cb) {
  const connectionPromise = stillConnecting(this.getDataSource(), this, arguments);
  if (connectionPromise) {
    return connectionPromise;
  }

  assert(arguments.length >= 1, 'At least one argument is required');
  if (data === undefined && options === undefined && cb === undefined) {
    assert(typeof query === 'object', 'Single argument must be data object');
    // findOrCreate(data);
    // query will be built from data, and method will return Promise
    data = query;
    query = {where: data};
  } else if (options === undefined && cb === undefined) {
    if (typeof data === 'function') {
      // findOrCreate(data, cb);
      // query will be built from data
      cb = data;
      data = query;
      query = {where: data};
    }
  } else if (cb === undefined) {
    if (typeof options === 'function') {
      // findOrCreate(query, data, cb)
      cb = options;
      options = {};
    }
  }

  cb = cb || utils.createPromiseCallback();
  query = query || {where: {}};
  data = data || {};
  options = options || {};

  assert(typeof query === 'object', 'The query argument must be an object');
  assert(typeof data === 'object', 'The data argument must be an object');
  assert(typeof options === 'object', 'The options argument must be an object');
  assert(typeof cb === 'function', 'The cb argument must be a function');

  const hookState = {};

  const Model = this;
  const self = this;
  const connector = Model.getConnector();

  function _findOrCreate(query, data, currentInstance) {
    function findOrCreateCallback(err, data, created) {
      if (err) return cb(err);
      const context = {
        Model: Model,
        data: data,
        isNewInstance: created,
        hookState: hookState,
        options: options,
      };
      Model.notifyObserversOf('loaded', context, function(err, ctx) {
        if (err) return cb(err);

        data = ctx.data;
        const Model = self.lookupModel(data);
        let obj;

        if (data) {
          const ctorOpts = {
            fields: query.fields,
            applySetters: false,
            persisted: true,
            // see https://github.com/strongloop/loopback-datasource-juggler/issues/1692
            applyDefaultValues: false,
          };
          obj = new Model(data, ctorOpts);
        }

        if (created) {
          const context = {
            Model: Model,
            instance: obj,
            isNewInstance: true,
            hookState: hookState,
            options: options,
          };
          Model.notifyObserversOf('after save', context, function(err) {
            if (cb.promise) {
              cb(err, [obj, created]);
            } else {
              cb(err, obj, created);
            }
          });
        } else {
          if (cb.promise) {
            cb(err, [obj, created]);
          } else {
            cb(err, obj, created);
          }
        }
      });
    }

    data = Model._sanitizeData(data, options);
    const context = {
      Model: Model,
      where: query.where,
      data: data,
      isNewInstance: true,
      currentInstance: currentInstance,
      hookState: hookState,
      options: options,
    };

    Model.notifyObserversOf('persist', context, function(err) {
      if (err) return cb(err);
      invokeConnectorMethod(connector, 'findOrCreate', Model, [query, self._forDB(context.data)],
        options, findOrCreateCallback);
    });
  }

  if (connector.findOrCreate) {
    query.limit = 1;

    try {
      this._normalize(query, options);
    } catch (err) {
      process.nextTick(function() {
        cb(err);
      });
      return cb.promise;
    }

    this.applyScope(query);

    const context = {
      Model: Model,
      query: query,
      hookState: hookState,
      options: options,
    };
    Model.notifyObserversOf('access', context, function(err, ctx) {
      if (err) return cb(err);

      const query = ctx.query;

      const enforced = {};
      const Model = self.lookupModel(data);
      const obj = data instanceof Model ? data : new Model(data);

      Model.applyProperties(enforced, obj);
      obj.setAttributes(enforced);

      const context = {
        Model: Model,
        instance: obj,
        isNewInstance: true,
        hookState: hookState,
        options: options,
      };
      Model.notifyObserversOf('before save', context, function(err, ctx) {
        if (err) return cb(err);

        const obj = ctx.instance;
        const data = obj.toObject(true);

        // options has precedence on model-setting
        if (options.validate === false) {
          return _findOrCreate(query, data, obj);
        }

        // only when options.validate is not set, take model-setting into consideration
        if (options.validate === undefined && Model.settings.automaticValidation === false) {
          return _findOrCreate(query, data, obj);
        }

        // validation required
        obj.isValid(function(valid) {
          if (valid) {
            _findOrCreate(query, data, obj);
          } else {
            cb(new ValidationError(obj), obj);
          }
        }, data, options);
      });
    });
  } else {
    Model.findOne(query, options, function(err, record) {
      if (err) return cb(err);
      if (record) {
        if (cb.promise) {
          return cb(null, [record, false]);
        } else {
          return cb(null, record, false);
        }
      }
      Model.create(data, options, function(err, record) {
        if (cb.promise) {
          cb(err, [record, record != null]);
        } else {
          cb(err, record, record != null);
        }
      });
    });
  }
  return cb.promise;
};

/**
 * Check whether a model instance exists in database
 *
 * @param {id} id Identifier of object (primary key value)
 * @param {Object} [options] Options
 * @param {Function} cb Callback function called with (err, exists: Bool)
 */
DataAccessObject.exists = function exists(id, options, cb) {
  const connectionPromise = stillConnecting(this.getDataSource(), this, arguments);
  if (connectionPromise) {
    return connectionPromise;
  }

  assert(arguments.length >= 1, 'The id argument is required');
  if (cb === undefined) {
    if (typeof options === 'function') {
      // exists(id, cb)
      cb = options;
      options = {};
    }
  }

  cb = cb || utils.createPromiseCallback();
  options = options || {};

  assert(typeof options === 'object', 'The options argument must be an object');
  assert(typeof cb === 'function', 'The cb argument must be a function');

  if (id !== undefined && id !== null && id !== '') {
    this.count(byIdQuery(this, id).where, options, function(err, count) {
      cb(err, err ? false : count === 1);
    });
  } else {
    process.nextTick(function() {
      cb(new Error(g.f('{{Model::exists}} requires the {{id}} argument')));
    });
  }
  return cb.promise;
};

/**
 * Find model instance by ID.
 *
 * Example:
 * ```js
 * User.findById(23, function(err, user) {
 *   console.info(user.id); // 23
 * });
 * ```
 *
 * @param {*} id Primary key value
 * @param {Object} [filter] The filter that contains `include` or `fields`.
 * Other settings such as `where`, `order`, `limit`, or `offset` will be
 * ignored.
 * @param {Object} [options] Options
 * @param {Function} cb Callback called with (err, instance)
 */
DataAccessObject.findById = function findById(id, filter, options, cb) {
  const connectionPromise = stillConnecting(this.getDataSource(), this, arguments);
  if (connectionPromise) {
    return connectionPromise;
  }

  assert(arguments.length >= 1, 'The id argument is required');

  if (options === undefined && cb === undefined) {
    if (typeof filter === 'function') {
      // findById(id, cb)
      cb = filter;
      filter = {};
    }
  } else if (cb === undefined) {
    if (typeof options === 'function') {
      // findById(id, query, cb)
      cb = options;
      options = {};
      if (typeof filter === 'object' && !(filter.include || filter.fields)) {
        // If filter doesn't have include or fields, assuming it's options
        options = filter;
        filter = {};
      }
    }
  }

  cb = cb || utils.createPromiseCallback();
  options = options || {};
  filter = filter || {};

  assert(typeof filter === 'object', 'The filter argument must be an object');
  assert(typeof options === 'object', 'The options argument must be an object');
  assert(typeof cb === 'function', 'The cb argument must be a function');

  if (isPKMissing(this, cb)) {
    return cb.promise;
  } else if (id == null || id === '') {
    process.nextTick(function() {
      cb(new Error(g.f('{{Model::findById}} requires the {{id}} argument')));
    });
  } else {
    const query = byIdQuery(this, id);
    if (filter.include) {
      query.include = filter.include;
    }
    if (filter.fields) {
      query.fields = filter.fields;
    }
    this.findOne(query, options, cb);
  }
  return cb.promise;
};

/**
 * Find model instances by ids
 * @param {Array} ids An array of ids
 * @param {Object} query Query filter
 * @param {Object} [options] O