provide database column default values via Loopback model description

lib/postgresql.js

@@ -236,7 +236,7 @@ PostgreSQL.prototype._categorizeProperties = function(model, data) {
   });
   var props = Object.keys(this._models[model].properties);
   var nonIdsInData = Object.keys(data).filter(function(key) {
-    return props.indexOf(key) !== -1 && ids.indexOf(key) === -1;
+    return props.indexOf(key) !== -1 && ids.indexOf(key) === -1 && data[key] !== undefined;
   });
   return {
     ids: ids,
@@ -387,6 +387,9 @@ PostgreSQL.prototype.toFields = function (model, data, forCreate) {
   var nonIdsInData = props.nonIdsInData;
   var query = [];
   if (forCreate) {
+      if(nonIdsInData.length == 0 && dataIdNames.length == 0) {
+          return 'default values';
+      }
     query.push('(');
     query.push(nonIdsInData.map(function (key) {
       return self.columnEscaped(model, key);
@@ -1273,6 +1276,8 @@ PostgreSQL.prototype.propertySettingsSQL = function (model, propName) {
   }
   var result = self.columnDataType(model, propName);
   if (!propertyCanBeNull.call(self, model, propName)) result = result + ' NOT NULL';
+
+  result += self.columnDbDefault(model, propName);
   return result;
 };
 
@@ -1384,6 +1389,20 @@ function escape(val) {
   return "'" + val + "'";
 }
 
+/*!
+ * Get the database-default value for column from given model property
+ *
+ * @param {String} model The model name
+ * @param {String} property The property name
+ * @returns {String} The column default value
+ */
+PostgreSQL.prototype.columnDbDefault = function(model, property) {
+  var columnMetadata = this.columnMetadata(model, property);
+  var colDefault = columnMetadata && columnMetadata.dbDefault;
+
+  return colDefault ? (' DEFAULT ' + columnMetadata.dbDefault): '';
+}
+
 /*!
  * Find the column type for a given model property
  *

test/postgresql.dbdefaults.test.js

@@ -0,0 +1,83 @@
+var should = require('should'),
+    assert = require('assert');
+var InvalidDefault, Post, db;
+
+describe('database default field values', function () {
+    before(function () {
+        db = getDataSource();
+
+        Post = db.define('PostWithDbDefaultValue', {
+            created: {
+                type: 'Date',
+                postgresql: {
+                    dbDefault: "now()"
+                }
+            },
+            defaultInt: {
+                type: 'Number',
+                postgresql: {
+                    dbDefault: "5"
+                }
+            },
+            oneMore: {
+                type: 'Number'
+            }
+        });
+
+        InvalidDefault = db.define('PostWithInvalidDbDefaultValue', {
+            created: {
+                type: 'Date',
+                postgresql: {
+                    dbDefault: "'5'"
+                }
+            }
+        });
+    });
+
+    it('should run migration', function (done) {
+        db.automigrate('PostWithDbDefaultValue', function () {
+            done();
+        });
+    });
+
+    it('should report inconsistent default values used', function (done) {
+        db.automigrate('PostWithInvalidDbDefaultValue', function (err) {
+            should.exists(err);
+            done();
+        });
+    });
+
+    it('should have \'now()\' default value in SQL column definition', function (done) {
+        var query = "select column_name, data_type, character_maximum_length, column_default " +
+            "from information_schema.columns where table_name = 'postwithdbdefaultvalue' and column_name='created'";
+
+        db.connector.query(query, function (err, results) {
+            assert.equal(results[0].column_default, "now()");
+            done(err);
+        });
+    });
+
+    it('should create a record with default value', function (done) {
+        Post.create({oneMore: 3}, function (err, p) {
+            should.not.exists(err);
+            Post.findOne({where: {defaultInt: 5}}, function (err, p) {
+                should.not.exists(err);
+                should.exists(p);
+                p.should.have.property('defaultInt', 5);
+                done();
+            });
+        });
+    });
+
+    it('should create a record with custom value', function (done) {
+        Post.create({oneMore: 2, defaultInt: 6}, function (err, p) {
+            should.not.exists(err);
+            Post.findOne({where: {defaultInt: 6}}, function (err, p) {
+                should.not.exists(err);
+                should.exists(p);
+                p.should.have.property('defaultInt', 6);
+                done();
+            });
+        });
+    });
+})