diff --git a/lib/model.js b/lib/model.js
index aaf5e29f..51a59397 100644
--- a/lib/model.js
+++ b/lib/model.js
@@ -158,10 +158,18 @@ ModelBaseClass.prototype._initProperties = function (data, options) {
       var def = properties[p]['default'];
       if (def !== undefined) {
         if (typeof def === 'function') {
-          self.__data[p] = def();
-        } else {
-          self.__data[p] = def;
+          if (def === Date) {
+            // FIXME: We should coerce the value in general
+            // This is a work around to {default: Date}
+            // Date() will return a string instead of Date
+            def = new Date();
+          } else {
+            def = def();
+          }
         }
+        // FIXME: We should coerce the value
+        // will implement it after we refactor the PropertyDefinition
+        self.__data[p] = def;
       }
     }
 
diff --git a/lib/relation-definition.js b/lib/relation-definition.js
index 55add0b9..bf32e5a3 100644
--- a/lib/relation-definition.js
+++ b/lib/relation-definition.js
@@ -60,10 +60,10 @@ function RelationDefinition(definition) {
   this.type = normalizeType(definition.type);
   assert(this.type, 'Invalid relation type: ' + definition.type);
   this.modelFrom = definition.modelFrom;
-  assert(this.modelFrom);
+  assert(this.modelFrom, 'Source model is required');
   this.keyFrom = definition.keyFrom;
   this.modelTo = definition.modelTo;
-  assert(this.modelTo);
+  assert(this.modelTo, 'Target model is required');
   this.keyTo = definition.keyTo;
   this.modelThrough = definition.modelThrough;
   this.keyThrough = definition.keyThrough;
@@ -106,6 +106,15 @@ function Relation(definition, modelInstance) {
   this.modelInstance = modelInstance;
 }
 
+Relation.prototype.resetCache = function (cache) {
+  cache = cache || undefined;
+  this.modelInstance.__cachedRelations[this.definition.name] = cache;
+};
+
+Relation.prototype.getCache = function () {
+  return this.modelInstance.__cachedRelations[this.definition.name];
+};
+
 /**
  * HasMany subclass
  * @param {RelationDefinition|Object} definition
@@ -124,6 +133,39 @@ function HasMany(definition, modelInstance) {
 
 util.inherits(HasMany, Relation);
 
+HasMany.prototype.removeFromCache = function (id) {
+  var cache = this.modelInstance.__cachedRelations[this.definition.name];
+  var idName = this.definition.modelTo.definition.idName();
+  if (Array.isArray(cache)) {
+    for (var i = 0, n = cache.length; i < n; i++) {
+      if (cache[i][idName] === id) {
+        return cache.splice(i, 1);
+      }
+    }
+  }
+  return null;
+};
+
+HasMany.prototype.addToCache = function (inst) {
+  if (!inst) {
+    return;
+  }
+  var cache = this.modelInstance.__cachedRelations[this.definition.name];
+  if (cache === undefined) {
+    cache = this.modelInstance.__cachedRelations[this.definition.name] = [];
+  }
+  var idName = this.definition.modelTo.definition.idName();
+  if (Array.isArray(cache)) {
+    for (var i = 0, n = cache.length; i < n; i++) {
+      if (cache[i][idName] === inst[idName]) {
+        cache[i] = inst;
+        return;
+      }
+    }
+    cache.push(inst);
+  }
+};
+
 /**
  * HasManyThrough subclass
  * @param {RelationDefinition|Object} definition
@@ -210,7 +252,7 @@ function findBelongsTo(modelFrom, modelTo, keyTo) {
     var rel = relations[keys[k]];
     if (rel.type === RelationTypes.belongsTo &&
       rel.modelTo === modelTo &&
-      rel.keyTo === keyTo) {
+      (keyTo === undefined || rel.keyTo === keyTo)) {
       return rel.keyFrom;
     }
   }
@@ -356,6 +398,7 @@ HasMany.prototype.findById = function (id, cb) {
 };
 
 HasMany.prototype.destroyById = function (id, cb) {
+  var self = this;
   var modelTo = this.definition.modelTo;
   var fk = this.definition.keyTo;
   var pk = this.definition.keyFrom;
@@ -369,6 +412,7 @@ HasMany.prototype.destroyById = function (id, cb) {
     }
     // Check if the foreign key matches the primary key
     if (inst[fk] && inst[fk].toString() === modelInstance[pk].toString()) {
+      self.removeFromCache(inst[fk]);
       inst.destroy(cb);
     } else {
       cb(new Error('Permission denied: foreign key does not match the primary key'));
@@ -379,6 +423,7 @@ HasMany.prototype.destroyById = function (id, cb) {
 // Create an instance of the target model and connect it to the instance of
 // the source model by creating an instance of the through model
 HasManyThrough.prototype.create = function create(data, done) {
+  var self = this;
   var definition = this.definition;
   var modelTo = definition.modelTo;
   var modelThrough = definition.modelThrough;
@@ -391,27 +436,28 @@ HasManyThrough.prototype.create = function create(data, done) {
   var modelInstance = this.modelInstance;
 
   // First create the target model
-  modelTo.create(data, function (err, ac) {
+  modelTo.create(data, function (err, to) {
     if (err) {
-      return done && done(err, ac);
+      return done && done(err, to);
     }
     // The primary key for the target model
-    var pk2 = modelTo.dataSource.idName(modelTo.modelName) || 'id';
+    var pk2 = definition.modelTo.definition.idName();
     var fk1 = findBelongsTo(modelThrough, definition.modelFrom,
       definition.keyFrom);
     var fk2 = findBelongsTo(modelThrough, definition.modelTo, pk2);
     var d = {};
     d[fk1] = modelInstance[definition.keyFrom];
-    d[fk2] = ac[pk2];
+    d[fk2] = to[pk2];
     // Then create the through model
-    modelThrough.create(d, function (e) {
+    modelThrough.create(d, function (e, through) {
       if (e) {
         // Undo creation of the target model
-        ac.destroy(function () {
+        to.destroy(function () {
           done && done(e);
         });
       } else {
-        done && done(err, ac);
+        self.addToCache(to);
+        done && done(err, to);
       }
     });
   });
@@ -422,9 +468,9 @@ HasManyThrough.prototype.create = function create(data, done) {
  * @param {Object|ID} acInst The actual instance or id value
  */
 HasManyThrough.prototype.add = function (acInst, done) {
+  var self = this;
   var definition = this.definition;
   var modelThrough = definition.modelThrough;
-  var modelTo = definition.modelTo;
   var pk1 = definition.keyFrom;
 
   var data = {};
@@ -434,7 +480,7 @@ HasManyThrough.prototype.add = function (acInst, done) {
     definition.keyFrom);
 
   // The primary key for the target model
-  var pk2 = modelTo.dataSource.idName(modelTo.modelName) || 'id';
+  var pk2 = definition.modelTo.definition.idName();
 
   var fk2 = findBelongsTo(modelThrough, definition.modelTo, pk2);
 
@@ -445,7 +491,14 @@ HasManyThrough.prototype.add = function (acInst, done) {
   data[fk2] = acInst[pk2] || acInst;
 
   // Create an instance of the through model
-  modelThrough.findOrCreate({where: query}, data, done);
+  modelThrough.findOrCreate({where: query}, data, function(err, ac) {
+    if(!err) {
+      if (acInst instanceof definition.modelTo) {
+        self.addToCache(acInst);
+      }
+    }
+    done(err, ac);
+  });
 };
 
 /**
@@ -453,13 +506,30 @@ HasManyThrough.prototype.add = function (acInst, done) {
  * @param {Object|ID) acInst The actual instance or id value
  */
 HasManyThrough.prototype.remove = function (acInst, done) {
-  var modelThrough = this.definition.modelThrough;
-  var fk2 = this.definition.keyThrough;
-  var pk = this.definition.keyFrom;
+  var self = this;
+  var definition = this.definition;
+  var modelThrough = definition.modelThrough;
+  var pk1 = definition.keyFrom;
 
-  var q = {};
-  q[fk2] = acInst[pk] || acInst;
-  modelThrough.deleteAll(q, done );
+  var query = {};
+
+  var fk1 = findBelongsTo(modelThrough, definition.modelFrom,
+    definition.keyFrom);
+
+  // The primary key for the target model
+  var pk2 = definition.modelTo.definition.idName();
+
+  var fk2 = findBelongsTo(modelThrough, definition.modelTo, pk2);
+
+  query[fk1] = this.modelInstance[pk1];
+  query[fk2] = acInst[pk2] || acInst;
+
+  modelThrough.deleteAll(query, function (err) {
+    if (!err) {
+      self.removeFromCache(query[fk2]);
+    }
+    done(err);
+  });
 };
 
 
@@ -539,6 +609,7 @@ RelationDefinition.belongsTo = function (modelFrom, modelTo, params) {
 };
 
 BelongsTo.prototype.create = function(targetModelData, cb) {
+  var self = this;
   var modelTo = this.definition.modelTo;
   var fk = this.definition.keyTo;
   var pk = this.definition.keyFrom;
@@ -547,6 +618,7 @@ BelongsTo.prototype.create = function(targetModelData, cb) {
   modelTo.create(targetModelData, function(err, targetModel) {
     if(!err) {
       modelInstance[fk] = targetModel[pk];
+      self.resetCache(targetModel);
       cb && cb(err, targetModel);
     } else {
       cb && cb(err);
@@ -571,11 +643,11 @@ BelongsTo.prototype.build = function(targetModelData) {
  * @returns {*}
  */
 BelongsTo.prototype.related = function (refresh, params) {
+  var self = this;
   var modelTo = this.definition.modelTo;
   var pk = this.definition.keyTo;
   var fk = this.definition.keyFrom;
   var modelInstance = this.modelInstance;
-  var relationName = this.definition.name;
 
   if (arguments.length === 1) {
     params = refresh;
@@ -585,13 +657,12 @@ BelongsTo.prototype.related = function (refresh, params) {
   }
 
   var cachedValue;
-  if (!refresh && modelInstance.__cachedRelations
-    && (modelInstance.__cachedRelations[relationName] !== undefined)) {
-    cachedValue = modelInstance.__cachedRelations[relationName];
+  if (!refresh) {
+    cachedValue = self.getCache();
   }
   if (params instanceof ModelBaseClass) { // acts as setter
     modelInstance[fk] = params[pk];
-    modelInstance.__cachedRelations[relationName] = params;
+    self.resetCache(params);
   } else if (typeof params === 'function') { // acts as async getter
     var cb = params;
     if (cachedValue === undefined) {
@@ -604,9 +675,10 @@ BelongsTo.prototype.related = function (refresh, params) {
         }
         // Check if the foreign key matches the primary key
         if (inst[pk] === modelInstance[fk]) {
+          self.resetCache(inst);
           cb(null, inst);
         } else {
-          cb(new Error('Permission denied'));
+          cb(new Error('Permission denied: foreign key does not match the primary key'));
         }
       });
       return modelInstance[fk];
@@ -618,7 +690,7 @@ BelongsTo.prototype.related = function (refresh, params) {
     return modelInstance[fk];
   } else { // setter
     modelInstance[fk] = params;
-    delete modelInstance.__cachedRelations[relationName];
+    self.resetCache();
   }
 };
 
@@ -734,15 +806,19 @@ RelationDefinition.hasOne = function (modelFrom, modelTo, params) {
  * @param {Object} The newly created target model instance
  */
 HasOne.prototype.create = function(targetModelData, cb) {
+  var self = this;
   var modelTo = this.definition.modelTo;
   var fk = this.definition.keyTo;
   var pk = this.definition.keyFrom;
   var modelInstance = this.modelInstance;
+  var relationName = this.definition.name
 
   targetModelData = targetModelData || {};
   targetModelData[fk] = modelInstance[pk];
   modelTo.create(targetModelData, function(err, targetModel) {
     if(!err) {
+      // Refresh the cache
+      self.resetCache(targetModel);
       cb && cb(err, targetModel);
     } else {
       cb && cb(err);
@@ -776,6 +852,7 @@ HasOne.prototype.build = function(targetModelData) {
  * @returns {Object}
  */
 HasOne.prototype.related = function (refresh, params) {
+  var self = this;
   var modelTo = this.definition.modelTo;
   var fk = this.definition.keyTo;
   var pk = this.definition.keyFrom;
@@ -790,13 +867,12 @@ HasOne.prototype.related = function (refresh, params) {
   }
 
   var cachedValue;
-  if (!refresh && modelInstance.__cachedRelations
-    && (modelInstance.__cachedRelations[relationName] !== undefined)) {
-    cachedValue = modelInstance.__cachedRelations[relationName];
+  if (!refresh) {
+    cachedValue = self.getCache();
   }
   if (params instanceof ModelBaseClass) { // acts as setter
     params[fk] = modelInstance[pk];
-    modelInstance.__cachedRelations[relationName] = params;
+    self.resetCache(params);
   } else if (typeof params === 'function') { // acts as async getter
     var cb = params;
     if (cachedValue === undefined) {
@@ -811,6 +887,7 @@ HasOne.prototype.related = function (refresh, params) {
         }
         // Check if the foreign key matches the primary key
         if (inst[fk] === modelInstance[pk]) {
+          self.resetCache(inst);
           cb(null, inst);
         } else {
           cb(new Error('Permission denied'));
@@ -825,6 +902,6 @@ HasOne.prototype.related = function (refresh, params) {
     return modelInstance[pk];
   } else { // setter
     params[fk] = modelInstance[pk];
-    delete modelInstance.__cachedRelations[relationName];
+    self.resetCache();
   }
 };
diff --git a/test/loopback-dl.test.js b/test/loopback-dl.test.js
index 095afb6c..aeda8992 100644
--- a/test/loopback-dl.test.js
+++ b/test/loopback-dl.test.js
@@ -264,7 +264,7 @@ describe('DataSource define model', function () {
       name: String,
       bio: ModelBuilder.Text,
       approved: Boolean,
-      joinedAt: Date,
+      joinedAt: {type: Date, default: Date},
       age: Number
     });
 
@@ -280,6 +280,8 @@ describe('DataSource define model', function () {
     assert.equal(user.name, 'Joe');
     assert.equal(user.group, 'G1');
 
+    assert(user.joinedAt instanceof Date);
+
     // setup relationships
     User.hasMany(Post, {as: 'posts', foreignKey: 'userId'});