loopback-datasource-juggler-regevbr/lib/dao.js

LoopBack DataSoure Juggler

// Copyright IBM Corp. 2013,2016. 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
 */
var g = require('strong-globalize')();
var async = require('async');
var jutil = require('./jutil');
var ValidationError = require('./validations').ValidationError;
var Relation = require('./relations.js');
var Inclusion = require('./include.js');
var List = require('./list.js');
var geo = require('./geo');
var Memory = require('./connectors/memory').Memory;
var utils = require('./utils');
var fieldsToArray = utils.fieldsToArray;
var removeUndefined = utils.removeUndefined;
var setScopeValuesFromWhere = utils.setScopeValuesFromWhere;
var idEquals = utils.idEquals;
var mergeQuery = utils.mergeQuery;
var util = require('util');
var assert = require('assert');
var BaseModel = require('./model');
var 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) {
    var self = this;
    var 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 (var key in from) {
    to[key] = from[key];
  }
}

function convertSubsetOfPropertiesByType(inst, data) {
  var typedData = {};
  for (var 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) {
  var props = model.definition.properties;
  var keys = Object.keys(data);
  var result = {}, key;
  for (var i = 0; i < keys.length; i++) {
    key = keys[i];
    if (props[key]) {
      result[key] = data[key];
    } else if (strict === 'throw') {
      cb(new Error(g.f('Unknown property: %s', key)));
      return;
    } else if (strict === 'validate') {
      inst.__unknownProperties.push(key);
    }
  }
  cb(null, result);
}

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

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

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

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

  return where[pk] === idValue;
}

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

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

DataAccessObject.applyProperties = function(data, inst) {
  var properties = this.definition.settings.properties;
  properties = properties || this.definition.settings.attributes;
  if (typeof properties === 'object') {
    util._extend(data, properties);
  } else if (typeof properties === 'function') {
    util._extend(data, properties.call(this, data, inst) || {});
  } else if (properties !== false) {
    var 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;
};

// Empty callback function
function noCallback(err, result) {
  // NOOP
  debug('callback is ignored: err=%j, result=%j', err, result);
}

/**
 * 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) {
  var connectionPromise = stillConnecting(this.getDataSource(), this, arguments);
  if (connectionPromise) {
    return connectionPromise;
  }

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

  var 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 || (Array.isArray(data) ? noCallback : 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');

  var 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 (var 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
      var errors = null;
      var data = [];
      for (var 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 data;
  }

  var enforced = {};
  var obj;
  var 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) {
    return cb(err);
  }

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

  var 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) {
        var _idName = idName(Model);
        var modelName = Model.modelName;
        var val = removeUndefined(obj.toObject(true));
        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;

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

                Model.notifyObserversOf('after save', context, function(err) {
                  cb(err, obj);
                  if (!err) Model.emit('changed', obj);
                });
              });
            });
          });
        }

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

          if (connector.create.length === 4) {
            connector.create(modelName, obj.constructor._forDB(context.data), options, createCallback);
          } else {
            connector.create(modelName, obj.constructor._forDB(context.data), createCallback);
          }
        });
      }, obj, cb);
    }, obj, cb);
  }

  // Does this make any sense? How would chaining be used here? -partap

  // for chaining
  return cb.promise || obj;
};

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

  // promise variant
  var promiseArgs = Array.prototype.slice.call(args);
  promiseArgs.callee = args.callee;
  var 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) {
  var 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');

  var hookState = {};

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

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

  var 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);

    var isOriginalQuery = isWhereByGivenId(Model, ctx.query.where, id);
    if (connector.updateOrCreate && isOriginalQuery) {
      var 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;
        var update = data;
        var inst = data;
        if (!(data instanceof Model)) {
          inst = new Model(data, {applyDefaultValues: false});
        }
        update = inst.toObject(false);

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

        var connector = self.getConnector();

        var 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;
        }

        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 = removeUndefined(update);
          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);
            if (connector.updateOrCreate.length === 4) {
              connector.updateOrCreate(Model.modelName, update, options, done);
            } else {
              connector.updateOrCreate(Model.modelName, update, done);
            }
          });
        }
        function done(err, data, info) {
          if (err) return cb(err);
          var 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);

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

              Model.notifyObserversOf('after save', context, function(err) {
                cb(err, obj);
                if (!err) {
                  Model.emit('changed', inst);
                }
              });
            }
          });
        }
      });
    } else {
      var 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);
          var 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) {
  var 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) {
    var err = new Error('data object cannot be empty!');
    err.statusCode = 400;
    process.nextTick(function() { cb(err); });
    return cb.promise;
  }
  var hookState = {};
  var self = this;
  var Model = this;
  var connector = Model.getConnector();
  var modelName = Model.modelName;
  var query = {where: where};
  var 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) {
      var 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;
        var update = data;
        var 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 = removeUndefined(ctx.where);
            ctx.where = Model._coerce(ctx.where);
            update = removeUndefined(update);
            update = Model._coerce(update);
          } 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);
            connector.upsertWithWhere(modelName, ctx.where, update, options, done);
          });
        }
        function done(err, data, info) {
          if (err) return cb(err);
          var 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);
            var obj;
            if (contxt.data && !(contxt.data instanceof Model)) {
              inst._initProperties(contxt.data, {persisted: true});
              obj = inst;
            } else {
              obj = contxt.data;
            }
            var 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 {
      var 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);
        var modelsLength = instances.length;
        if (modelsLength === 0)  {
          self.create(data, options, cb);
        } else if (modelsLength === 1) {
          var modelInst = instances[0];
          modelInst.updateAttributes(data, options, cb);
        } else {
          process.nextTick(function() {
            var 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) {
  var 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');

  var hookState = {};

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

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

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

  var strict = inst.__strict;
  var 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);

    var isOriginalQuery = isWhereByGivenId(Model, ctx.query.where, id);
    var where = ctx.query.where;
    if (connector.replaceOrCreate && isOriginalQuery) {
      var context = {
        Model: Model,
        instance: inst,
        hookState: hookState,
        options: options,
      };
      Model.notifyObserversOf('before save', context, function(err, ctx) {
        if (err) return cb(err);
        var 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);

          var connector = self.getConnector();

          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 = removeUndefined(update);
            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);
              connector.replaceOrCreate(Model.modelName, context.data, options, done);
            });
          }
          function done(err, data, info) {
            if (err) return cb(err);
            var 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);

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

                Model.notifyObserversOf('after save', context, function(err) {
                  if (!err) Model.emit('changed', inst);

                  cb(err, obj, info);
                });
              }
            });
          }
        }
      });
    } else {
      var 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)]`
          var pkName = idName(Model);
          delete data[pkName];
          if (found) id = found[pkName];
        }
        if (found) {
          self.replaceById(id, data, options, cb);
        } else {
          Model = self.lookupModel(data);
          var 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) {
  var 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');

  var hookState = {};

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

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

        var obj, Model = self.lookupModel(data);

        if (data) {
          var ctorOpts = {
            fields: query.fields,
            applySetters: false,
            persisted: true,
          };
          if (Model.settings.applyDefaultsOnReads === false) {
            ctorOpts.applyDefaultValues = false;
          }
          obj = new Model(data, ctorOpts);
        }

        if (created) {
          var 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);
            }
            if (!err) Model.emit('changed', obj);
          });
        } else {
          if (cb.promise) {
            cb(err, [obj, created]);
          } else {
            cb(err, obj, created);
          }
        }
      });
    }

    data = removeUndefined(data);
    var 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);

      if (connector.findOrCreate.length === 5) {
        connector.findOrCreate(modelName, query, self._forDB(context.data), options, findOrCreateCallback);
      } else {
        connector.findOrCreate(modelName, query, self._forDB(context.data), findOrCreateCallback);
      }
    });
  }

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

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

    this.applyScope(query);

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

      var query = ctx.query;

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

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

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

        var obj = ctx.instance;
        var 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) {
  var 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) {
  var 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 {
    var 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] Options
 * @param {Function} cb Callback called with (err, instance)
 */
DataAccessObject.findByIds = function(ids, query, options, cb) {
  if (options === undefined && cb === undefined) {
    if (typeof query === 'function') {
      // findByIds(ids, cb)
      cb = query;
      query = {};
    }
  } else if (cb === undefined) {
    if (typeof options === 'function') {
      // findByIds(ids, query, cb)
      cb = options;
      options = {};
    }
  }

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

  assert(Array.isArray(ids), 'The ids argument must be an array');
  assert(typeof query === 'object', 'The query 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 (ids.length === 0) {
    process.nextTick(function() { cb(null, []); });
    return cb.promise;
  }

  var filter = {where: {}};
  var pk = idName(this);
  filter.where[pk] = {inq: [].concat(ids)};
  mergeQuery(filter, query || {});

  // to know if the result need to be sorted by ids or not
  // this variable need to be initialized before the call to find, because filter is updated during the call with an order
  var toSortObjectsByIds = filter.order ? false : true;

  this.find(filter, options, function(err, results) {
    cb(err, toSortObjectsByIds ? utils.sortObjectsByIds(pk, ids, results) : results);
  });
  return cb.promise;
};

function convertNullToNotFoundError(ctx, cb) {
  if (ctx.result !== null) return cb();

  var modelName = ctx.method.sharedClass.name;
  var id = ctx.getArgByName('id');
  var msg = g.f('Unknown "%s" {{id}} "%s".', modelName, id);
  var error = new Error(msg);
  error.statusCode = error.status = 404;
  cb(error);
}

// alias function for backwards compat.
DataAccessObject.all = function() {
  return DataAccessObject.find.apply(this, arguments);
};

/**
 * Get settings via hiarchical determiniation
 *
 * @param {String} key The setting key
 */
DataAccessObject._getSetting = function(key) {
  // Check for settings in model
  var m = this.definition;
  if (m && m.settings && m.settings[key]) {
    return m.settings[key];
  }

  // Check for settings in connector
  var ds = this.getDataSource();
  if (ds && ds.settings && ds.settings[key]) {
    return ds.settings[key];
  }

  return;
};

var operators = {
  gt: '>',
  gte: '>=',
  lt: '<',
  lte: '<=',
  between: 'BETWEEN',
  inq: 'IN',
  nin: 'NOT IN',
  neq: '!=',
  like: 'LIKE',
  nlike: 'NOT LIKE',
  ilike: 'ILIKE',
  nilike: 'NOT ILIKE',
  regexp: 'REGEXP',
};

/*
 * Normalize the filter object and throw errors if invalid values are detected
 * @param {Object} filter The query filter object
 * @returns {Object} The normalized filter object
 * @private
 */
DataAccessObject._normalize = function(filter) {
  if (!filter) {
    return undefined;
  }
  var err = null;
  if ((typeof filter !== 'object') || Array.isArray(filter)) {
    err = new Error(g.f('The query filter %j is not an {{object}}', filter));
    err.statusCode = 400;
    throw err;
  }
  if (filter.limit || filter.skip || filter.offset) {
    var limit = Number(filter.limit || 100);
    var offset = Number(filter.skip || filter.offset || 0);
    if (isNaN(limit) || limit <= 0 || Math.ceil(limit) !== limit) {
      err = new Error(g.f('The {{limit}} parameter %j is not valid',
        filter.limit));
      err.statusCode = 400;
      throw err;
    }
    if (isNaN(offset) || offset < 0 || Math.ceil(offset) !== offset) {
      err = new Error(g.f('The {{offset/skip}} parameter %j is not valid',
          filter.skip || filter.offset));
      err.statusCode = 400;
      throw err;
    }
    filter.limit = limit;
    filter.offset = offset;
    filter.skip = offset;
  }

  if (filter.order) {
    var order = filter.order;
    if (!Array.isArray(order)) {
      order = [order];
    }
    var fields = [];
    for (var i = 0, m = order.length; i < m; i++) {
      if (typeof order[i] === 'string') {
        // Normalize 'f1 ASC, f2 DESC, f3' to ['f1 ASC', 'f2 DESC', 'f3']
        var tokens = order[i].split(/(?:\s*,\s*)+/);
        for (var t = 0, n = tokens.length; t < n; t++) {
          var token = tokens[t];
          if (token.length === 0) {
            // Skip empty token
            continue;
          }
          var parts = token.split(/\s+/);
          if (parts.length >= 2) {
            var dir = parts[1].toUpperCase();
            if (dir === 'ASC' || dir === 'DESC') {
              token = parts[0] + ' ' + dir;
            } else {
              err = new Error(g.f('The {{order}} %j has invalid direction', token));
              err.statusCode = 400;
              throw err;
            }
          }
          fields.push(token);
        }
      } else {
        err = new Error(g.f('The order %j is not valid', order[i]));
        err.statusCode = 400;
        throw err;
      }
    }
    if (fields.length === 1 && typeof filter.order === 'string') {
      filter.order = fields[0];
    } else {
      filter.order = fields;
    }
  }

  // normalize fields as array of included property names
  if (filter.fields) {
    filter.fields = fieldsToArray(filter.fields,
      Object.keys(this.definition.properties), this.settings.strict);
  }

  var handleUndefined =  this._getSetting('normalizeUndefinedInQuery');
  // alter configuration of how removeUndefined handles undefined values
  filter = removeUndefined(filter, handleUndefined);
  this._coerce(filter.where);
  return filter;
};

function DateType(arg) {
  var d = new Date(arg);
  if (isNaN(d.getTime())) {
    throw new Error(g.f('Invalid date: %s', arg));
  }
  return d;
}

function BooleanType(arg) {
  if (typeof arg === 'string') {
    switch (arg) {
      case 'true':
      case '1':
        return true;
      case 'false':
      case '0':
        return false;
    }
  }
  if (arg == null) {
    return null;
  }
  return Boolean(arg);
}

function NumberType(val) {
  var num = Number(val);
  return !isNaN(num) ? num : val;
}

function coerceArray(val) {
  if (Array.isArray(val)) {
    return val;
  }

  if (!utils.isPlainObject(val)) {
    throw new Error(g.f('Value is not an {{array}} or {{object}} with sequential numeric indices'));
  }

  // It is an object, check if empty
  var props = Object.keys(val);

  if (props.length === 0) {
    throw new Error(g.f('Value is an empty {{object}}'));
  }

  var arrayVal = new Array(props.length);
  for (var i = 0; i < arrayVal.length; ++i) {
    if (!val.hasOwnProperty(i)) {
      throw new Error(g.f('Value is not an {{array}} or {{object}} with sequential numeric indices'));
    }

    arrayVal[i] = val[i];
  }

  return arrayVal;
}

/*
 * Coerce values based the property types
 * @param {Object} where The where clause
 * @returns {Object} The coerced where clause
 * @private
 */
DataAccessObject._coerce = function(where, props) {
  var self = this;
  if (!where) {
    return where;
  }

  props = props || self.definition.properties;

  var err;
  if (typeof where !== 'object' || Array.isArray(where)) {
    err = new Error(g.f('The where clause %j is not an {{object}}', where));
    err.statusCode = 400;
    throw err;
  }

  for (var p in where) {
    // Handle logical operators
    if (p === 'and' || p === 'or' || p === 'nor') {
      var clauses = where[p];
      try {
        clauses = coerceArray(clauses);
      } catch (e) {
        err = new Error(g.f('The %s operator has invalid clauses %j: %s', p, clauses, e.message));
        err.statusCode = 400;
        throw err;
      }

      for (var k = 0; k < clauses.length; k++) {
        self._coerce(clauses[k]);
      }

      continue;
    }

    if (p.match(/\./)) {
      var model = p.split('.')[0];
      var prop = p.split('.').slice(1);

      if (props[model]) {
        var clause = {};
        clause[prop] = where[p];
        var type = Array.isArray(props[model].type) ? props[model].type[0] : props[model].type;
        if (type && type.definition && type.definition.properties) {
          where[p] = self._coerce(clause, type.definition.properties)[prop];
          continue;
        }
        // else fall-back to old/default coercion

        continue;
      }
    }

    var DataType = props[p] && props[p].type;
    if (!DataType) {
      continue;
    }
    if (Array.isArray(DataType) || DataType === Array) {
      DataType = DataType[0];
    }
    if (DataType === Date) {
      DataType = DateType;
    } else if (DataType === Boolean) {
      DataType = BooleanType;
    } else if (DataType === Number) {
      // This fixes a regression in mongodb connector
      // For numbers, only convert it produces a valid number
      // LoopBack by default injects a number id. We should fix it based
      // on the connector's input, for example, MongoDB should use string
      // while RDBs typically use number
      DataType = NumberType;
    }

    if (!DataType) {
      continue;
    }

    if (DataType.prototype instanceof BaseModel) {
      continue;
    }

    if (DataType === geo.GeoPoint) {
      // Skip the GeoPoint as the near operator breaks the assumption that
      // an operation has only one property
      // We should probably fix it based on
      // http://docs.mongodb.org/manual/reference/operator/query/near/
      // The other option is to make operators start with $
      continue;
    }

    var val = where[p];
    if (val === null || val === undefined) {
      continue;