diff --git a/.idea/orm.iml b/.idea/orm.iml
index 5ef6ddeb..0afafb50 100644
--- a/.idea/orm.iml
+++ b/.idea/orm.iml
@@ -16,6 +16,5 @@
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" name="Dart SDK" level="project" />
-    <orderEntry type="library" name="Dart Packages" level="project" />
   </component>
 </module>
\ No newline at end of file
diff --git a/angel_orm_generator/lib/src/builder/orm/build_context.dart b/angel_orm_generator/lib/src/builder/orm/build_context.dart
index d2b70516..2bf880dd 100644
--- a/angel_orm_generator/lib/src/builder/orm/build_context.dart
+++ b/angel_orm_generator/lib/src/builder/orm/build_context.dart
@@ -142,7 +142,7 @@ Future<PostgresBuildContext> buildContext(
       );
     }
 
-    if (column != null) {
+    if (column != null && column.type == null) {
       column = new Column(
         nullable: column.nullable,
         length: column.length,
diff --git a/angel_orm_generator/lib/src/builder/orm/migration.dart b/angel_orm_generator/lib/src/builder/orm/migration.dart
index 0c7f105a..b92f0692 100644
--- a/angel_orm_generator/lib/src/builder/orm/migration.dart
+++ b/angel_orm_generator/lib/src/builder/orm/migration.dart
@@ -48,18 +48,19 @@ class MigrationGenerator extends GeneratorForAnnotation<ORM> {
 
     var clazz = new ClassBuilder('${ctx.modelClassName}Migration',
         asExtends: new TypeBuilder('Migration'));
-    clazz..addMethod(buildUpMigration(ctx))..addMethod(buildDownMigration(ctx));
+    clazz..addMethod(buildUpMigration(ctx, lib))..addMethod(buildDownMigration(ctx));
 
     return lib..addMember(clazz);
   }
 
-  MethodBuilder buildUpMigration(PostgresBuildContext ctx) {
+  MethodBuilder buildUpMigration(PostgresBuildContext ctx, LibraryBuilder lib) {
     var meth = new MethodBuilder('up')..addPositional(_schemaParam);
     var closure = new MethodBuilder.closure()
       ..addPositional(parameter('table'));
     var table = reference('table');
 
     List<String> dup = [];
+    bool hasOrmImport = false;
     ctx.columnInfo.forEach((name, col) {
       var key = ctx.resolveFieldName(name);
 
@@ -81,8 +82,7 @@ class MigrationGenerator extends GeneratorForAnnotation<ORM> {
       List<ExpressionBuilder> positional = [literal(key)];
       Map<String, ExpressionBuilder> named = {};
 
-      if (autoIdAndDateFields != false && name == 'id')
-        methodName = 'serial';
+      if (autoIdAndDateFields != false && name == 'id') methodName = 'serial';
 
       if (methodName == null) {
         switch (col.type) {
@@ -115,6 +115,11 @@ class MigrationGenerator extends GeneratorForAnnotation<ORM> {
             methodName = 'timeStamp';
             break;
           default:
+            if (!hasOrmImport) {
+              hasOrmImport = true;
+              lib.addDirective(new ImportBuilder('package:angel_orm/angel_orm.dart'));
+            }
+
             ExpressionBuilder provColumn;
             var colType = new TypeBuilder('Column');
             var columnTypeType = new TypeBuilder('ColumnType');
diff --git a/angel_orm_generator/test/models/author.up.g.sql b/angel_orm_generator/test/models/author.up.g.sql
index 3ea50c88..4be12feb 100644
--- a/angel_orm_generator/test/models/author.up.g.sql
+++ b/angel_orm_generator/test/models/author.up.g.sql
@@ -1,5 +1,5 @@
 CREATE TEMPORARY TABLE "authors" (
-  "id" varchar,
+  "id" serial,
   "name" varchar UNIQUE,
   "created_at" timestamp,
   "updated_at" timestamp,
diff --git a/angel_orm_generator/test/models/book.up.g.sql b/angel_orm_generator/test/models/book.up.g.sql
index 125ff38d..465e1f07 100644
--- a/angel_orm_generator/test/models/book.up.g.sql
+++ b/angel_orm_generator/test/models/book.up.g.sql
@@ -1,5 +1,5 @@
 CREATE TEMPORARY TABLE "books" (
-  "id" varchar,
+  "id" serial,
   "name" varchar,
   "created_at" timestamp,
   "updated_at" timestamp,
diff --git a/angel_orm_generator/test/models/car.up.g.sql b/angel_orm_generator/test/models/car.up.g.sql
index ce6adb74..4cfacf16 100644
--- a/angel_orm_generator/test/models/car.up.g.sql
+++ b/angel_orm_generator/test/models/car.up.g.sql
@@ -1,5 +1,5 @@
 CREATE TEMPORARY TABLE "cars" (
-  "id" varchar,
+  "id" serial,
   "make" varchar,
   "description" varchar,
   "family_friendly" boolean,
diff --git a/angel_orm_generator/test/models/foot.up.g.sql b/angel_orm_generator/test/models/foot.up.g.sql
index 2635e5f3..8b9583a0 100644
--- a/angel_orm_generator/test/models/foot.up.g.sql
+++ b/angel_orm_generator/test/models/foot.up.g.sql
@@ -1,5 +1,5 @@
 CREATE TEMPORARY TABLE "foots" (
-  "id" varchar,
+  "id" serial,
   "leg_id" int,
   "n_toes" int,
   "created_at" timestamp,
diff --git a/angel_orm_generator/test/models/fruit.up.g.sql b/angel_orm_generator/test/models/fruit.up.g.sql
index f5b5fefe..558745c8 100644
--- a/angel_orm_generator/test/models/fruit.up.g.sql
+++ b/angel_orm_generator/test/models/fruit.up.g.sql
@@ -1,5 +1,5 @@
 CREATE TEMPORARY TABLE "fruits" (
-  "id" varchar,
+  "id" serial,
   "tree_id" int,
   "common_name" varchar,
   "created_at" timestamp,
diff --git a/angel_orm_generator/test/models/leg.up.g.sql b/angel_orm_generator/test/models/leg.up.g.sql
index 145ee9bd..6748f79c 100644
--- a/angel_orm_generator/test/models/leg.up.g.sql
+++ b/angel_orm_generator/test/models/leg.up.g.sql
@@ -1,5 +1,5 @@
 CREATE TEMPORARY TABLE "legs" (
-  "id" varchar,
+  "id" serial,
   "name" varchar,
   "created_at" timestamp,
   "updated_at" timestamp,
diff --git a/angel_orm_generator/test/models/role.up.g.sql b/angel_orm_generator/test/models/role.up.g.sql
index 649ea5dc..0cfadc10 100644
--- a/angel_orm_generator/test/models/role.up.g.sql
+++ b/angel_orm_generator/test/models/role.up.g.sql
@@ -1,5 +1,5 @@
 CREATE TEMPORARY TABLE "roles" (
-  "id" varchar,
+  "id" serial,
   "name" varchar,
   "created_at" timestamp,
   "updated_at" timestamp,
diff --git a/angel_orm_generator/test/models/tree.migration.g.dart b/angel_orm_generator/test/models/tree.migration.g.dart
index 11ed9d2f..c0feec10 100644
--- a/angel_orm_generator/test/models/tree.migration.g.dart
+++ b/angel_orm_generator/test/models/tree.migration.g.dart
@@ -5,13 +5,14 @@
 // **************************************************************************
 
 import 'package:angel_migration/angel_migration.dart';
+import 'package:angel_orm/angel_orm.dart';
 
 class TreeMigration extends Migration {
   @override
   up(Schema schema) {
     schema.create('trees', (table) {
       table.serial('id')..primaryKey();
-      table.integer('rings')..unique();
+      table.declare('rings', new ColumnType('smallint'))..unique();
       table.timeStamp('created_at');
       table.timeStamp('updated_at');
     });
diff --git a/angel_orm_generator/test/models/tree.up.g.sql b/angel_orm_generator/test/models/tree.up.g.sql
index a1bde855..0acebf9e 100644
--- a/angel_orm_generator/test/models/tree.up.g.sql
+++ b/angel_orm_generator/test/models/tree.up.g.sql
@@ -1,6 +1,6 @@
 CREATE TEMPORARY TABLE "trees" (
-  "id" varchar,
-  "rings" int UNIQUE,
+  "id" serial,
+  "rings" smallint UNIQUE,
   "created_at" timestamp,
   "updated_at" timestamp,
   UNIQUE(rings),
diff --git a/angel_orm_generator/test/models/user.up.g.sql b/angel_orm_generator/test/models/user.up.g.sql
index 2ac08fb4..b536a5a5 100644
--- a/angel_orm_generator/test/models/user.up.g.sql
+++ b/angel_orm_generator/test/models/user.up.g.sql
@@ -1,5 +1,5 @@
 CREATE TEMPORARY TABLE "users" (
-  "id" varchar,
+  "id" serial,
   "username" varchar,
   "password" varchar,
   "email" varchar,