Define the 'DECIMAL' data-type similar to how a FLOAT is defined.

This gives us the possibility to use "instanceof DECIMAL" when needed.

lib/data-types.js

@@ -46,6 +46,10 @@ var BLOB = function() {
   return BLOB.prototype.construct.apply(this, [BLOB].concat(Array.prototype.slice.apply(arguments)))
 }
 
+var DECIMAL = function() {
+  return DECIMAL.prototype.construct.apply(this, [DECIMAL].concat(Array.prototype.slice.apply(arguments)))
+}
+
 FLOAT._type = FLOAT
 FLOAT._typeName = 'FLOAT'
 INTEGER._type = INTEGER
@@ -56,8 +60,11 @@ STRING._type = STRING
 STRING._typeName = 'VARCHAR'
 BLOB._type = BLOB
 BLOB._typeName = 'BLOB'
+DECIMAL._type = DECIMAL
+DECIMAL._typeName = 'DECIMAL'
+
 
-BLOB.toString = STRING.toString = INTEGER.toString = FLOAT.toString = BIGINT.toString = function() {
+BLOB.toString = STRING.toString = INTEGER.toString = FLOAT.toString = BIGINT.toString = DECIMAL.toString = function() {
   return new this._type().toString()
 }
 
@@ -145,6 +152,47 @@ FLOAT.prototype = BIGINT.prototype = INTEGER.prototype = {
   }
 }
 
+DECIMAL.prototype = {
+
+  construct: function(RealType, precision, scale) {
+    if (this instanceof RealType) {
+      this._typeName = RealType._typeName
+      if (typeof precision === 'number') {
+        this._precision = precision
+      } else {
+        this._precision = 0
+      }
+      if (typeof scale === 'number') {
+        this._scale = scale
+      } else {
+        this._scale = 0
+      }
+    } else {
+      return new RealType(precision, scale)
+    }
+  },
+
+  get type() {
+    return 'DECIMAL'
+  },
+
+  get PRECISION() {
+    return this._precision
+  },
+
+  get SCALE() {
+    return this._scale
+  },
+
+  toString: function() {
+    if (this._precision || this._scale) {
+      return 'DECIMAL(' + this._precision + ',' + this._scale + ')'
+    }
+
+    return 'DECIMAL'
+  }
+}
+
 var unsignedDesc = {
   get: function() {
     return new this._type(undefined, undefined, true)
@@ -163,11 +211,18 @@ var typeDesc = {
   }
 }
 
+var decimalDesc = {
+  get: function() {
+    return new this._type(undefined, undefined, undefined)
+  }
+}
+
 Object.defineProperty(STRING,  'type', typeDesc)
 Object.defineProperty(INTEGER, 'type', typeDesc)
 Object.defineProperty(BIGINT,  'type', typeDesc)
 Object.defineProperty(FLOAT,   'type', typeDesc)
 Object.defineProperty(BLOB,    'type', typeDesc)
+Object.defineProperty(DECIMAL, 'type', typeDesc)
 
 Object.defineProperty(INTEGER, 'UNSIGNED', unsignedDesc)
 Object.defineProperty(BIGINT,  'UNSIGNED', unsignedDesc)
@@ -177,6 +232,9 @@ Object.defineProperty(INTEGER, 'ZEROFILL', zerofillDesc)
 Object.defineProperty(BIGINT,  'ZEROFILL', zerofillDesc)
 Object.defineProperty(FLOAT,   'ZEROFILL', zerofillDesc)
 
+Object.defineProperty(DECIMAL, 'PRECISION', decimalDesc)
+Object.defineProperty(DECIMAL, 'SCALE', decimalDesc)
+
 module.exports = {
   STRING: STRING,
 
@@ -188,6 +246,7 @@ module.exports = {
   FLOAT: FLOAT,
   NOW: 'NOW',
   BLOB: BLOB,
+  DECIMAL: DECIMAL,
   UUID: 'UUID',
   UUIDV1: 'UUIDV1',
   UUIDV4: 'UUIDV4',
@@ -207,16 +266,6 @@ module.exports = {
     return result
   },
 
-  get DECIMAL() {
-    var result = function(precision, scale) {
-      return 'DECIMAL(' + precision + ',' + scale + ')'
-    }
-
-    result.toString = result.valueOf = function() { return 'DECIMAL' }
-
-    return result
-  },
-
   ARRAY: function(type) { return type + '[]' },
 
   get HSTORE() {

test/data-types.test.js

@@ -11,11 +11,6 @@ describe(Support.getTestDialectTeaser('DataTypes'), function() {
     done()
   })
 
-  it('should return DECIMAL(10,2) for the default decimal type with arguments', function(done) {
-    expect(Sequelize.DECIMAL(10, 2)).to.equal('DECIMAL(10,2)')
-    done()
-  })
-
   var tests = [
     [Sequelize.STRING, 'STRING', 'VARCHAR(255)'],
     [Sequelize.STRING(1234), 'STRING(1234)', 'VARCHAR(1234)'],
@@ -61,7 +56,10 @@ describe(Support.getTestDialectTeaser('DataTypes'), function() {
     [Sequelize.FLOAT(11, 12).UNSIGNED, 'FLOAT(11,12).UNSIGNED', 'FLOAT(11,12) UNSIGNED'],
     [Sequelize.FLOAT(11, 12).UNSIGNED.ZEROFILL,'FLOAT(11,12).UNSIGNED.ZEROFILL','FLOAT(11,12) UNSIGNED ZEROFILL'],
     [Sequelize.FLOAT(11, 12).ZEROFILL,'FLOAT(11,12).ZEROFILL', 'FLOAT(11,12) ZEROFILL'],
-    [Sequelize.FLOAT(11, 12).ZEROFILL.UNSIGNED,'FLOAT(11,12).ZEROFILL.UNSIGNED', 'FLOAT(11,12) UNSIGNED ZEROFILL']
+    [Sequelize.FLOAT(11, 12).ZEROFILL.UNSIGNED,'FLOAT(11,12).ZEROFILL.UNSIGNED', 'FLOAT(11,12) UNSIGNED ZEROFILL'],
+
+    [Sequelize.DECIMAL, 'DECIMAL', 'DECIMAL'],
+    [Sequelize.DECIMAL(10,2), 'DECIMAL(10,2)','DECIMAL(10,2)']
   ]
 
   tests.forEach(function(test) {