allow functions as value for 'defaultValue' property

lib/dao-factory.js

@@ -172,9 +172,8 @@ module.exports = (function() {
         self.DAO.prototype.booleanValues.push(name);
       }
       if (definition.hasOwnProperty('defaultValue')) {
-        self.DAO.prototype.defaultValues[name] = function() {
-          return Utils.toDefaultValue(definition.defaultValue)
-        }
+	self.DAO.prototype.defaultValues[name] = Utils._.partial(
+	  Utils.toDefaultValue, definition.defaultValue)
       }
 
       if (definition.hasOwnProperty('validate')) {

lib/dialects/mysql/query-generator.js

@@ -529,7 +529,7 @@ module.exports = (function() {
           }
 
           // Blobs/texts cannot have a defaultValue
-          if (dataType.type !== "TEXT" && dataType.type._binary !== true && (dataType.defaultValue !== undefined) && (dataType.defaultValue != DataTypes.NOW)) {
+	  if (dataType.type !== "TEXT" && dataType.type._binary !== true && Utils.defaultValueSchemable(dataType.defaultValue)) {
             template += " DEFAULT " + this.escape(dataType.defaultValue)
           }
 

lib/dialects/postgres/query-generator.js

@@ -650,7 +650,10 @@ module.exports = (function() {
             template += " SERIAL"
           }
 
-          if (dataType.defaultValue !== undefined) {
+	  if (Utils.defaultValueSchemable(dataType.defaultValue)) {
+	    // TODO thoroughly check that DataTypes.NOW will properly
+	    // get populated on all databases as DEFAULT value
+	    // i.e. mysql requires: DEFAULT CURRENT_TIMESTAMP
             template += " DEFAULT <%= defaultValue %>"
             replacements.defaultValue = this.escape(dataType.defaultValue)
           }

lib/dialects/sqlite/query-generator.js

@@ -313,7 +313,10 @@ module.exports = (function() {
             template += " NOT NULL"
           }
 
-          if (dataType.defaultValue !== undefined) {
+	  if (Utils.defaultValueSchemable(dataType.defaultValue)) {
+	    // TODO thoroughly check that DataTypes.NOW will properly
+	    // get populated on all databases as DEFAULT value
+	    // i.e. mysql requires: DEFAULT CURRENT_TIMESTAMP
             template += " DEFAULT <%= defaultValue %>"
             replacements.defaultValue = this.escape(dataType.defaultValue)
           }

lib/utils.js

@@ -373,7 +373,32 @@ var Utils = module.exports = {
   },
 
   toDefaultValue: function(value) {
-    return (value === DataTypes.NOW) ? Utils.now() : value
+    if (lodash.isFunction(value)) {
+      return value()
+    } else {
+      return (value === DataTypes.NOW) ? Utils.now() : value
+    }
+  },
+
+  /**
+   * Determine if the default value provided exists and can be described
+   * in a db schema using the DEFAULT directive.
+   *
+   * @param  {*} value Any default value.
+   * @return {boolean} yes / no.
+   */
+  defaultValueSchemable: function(value) {
+    if (typeof value === 'undefined') {return false}
+
+    // TODO this will be schemable when all supported db
+    // have been normalized for this case
+    if (value === DataTypes.NOW) {return false}
+
+    if (lodash.isFunction(value)) {
+      return false
+    }
+
+    return true
   },
 
   setAttributes: function(hash, identifier, instance, prefix) {