diff --git a/migrations/20181119152303_timestamps_to_bigint.js b/migrations/20181119152303_timestamps_to_bigint.js
index 4aaeac8..45bf937 100644
--- a/migrations/20181119152303_timestamps_to_bigint.js
+++ b/migrations/20181119152303_timestamps_to_bigint.js
@@ -1,49 +1,41 @@
 exports.up = function (knex, Promise) {
   return Promise.all([
-    knex.schema.table('user', t => {
-      t.dropColumns('created_at', 'updated_at')
-      t.bigInteger('created_at')
-      t.bigInteger('updated_at')
+    knex.schema.alterTable('user', t => {
+      t.bigInteger('created_at').alter()
+      t.bigInteger('updated_at').alter()
     }),
-    knex.schema.table('passport', t => {
-      t.dropColumns('created_at', 'updated_at')
-      t.bigInteger('created_at')
-      t.bigInteger('updated_at')
+    knex.schema.alterTable('passport', t => {
+      t.bigInteger('created_at').alter()
+      t.bigInteger('updated_at').alter()
     }),
-    knex.schema.table('targeturl', t => {
-      t.dropColumns('created_at', 'updated_at')
-      t.bigInteger('created_at')
-      t.bigInteger('updated_at')
+    knex.schema.alterTable('targeturl', t => {
+      t.bigInteger('created_at').alter()
+      t.bigInteger('updated_at').alter()
     }),
-    knex.schema.table('book', t => {
-      t.dropColumns('created_at', 'updated_at')
-      t.bigInteger('created_at')
-      t.bigInteger('updated_at')
+    knex.schema.alterTable('book', t => {
+      t.bigInteger('created_at').alter()
+      t.bigInteger('updated_at').alter()
     })
   ])
 }
 
 exports.down = function (knex, Promise) {
   return Promise.all([
-    knex.schema.table('user', t => {
-      t.dropColumns('created_at', 'updated_at')
-      t.integer('created_at')
-      t.integer('updated_at')
+    knex.schema.alterTable('user', t => {
+      t.integer('created_at').alter()
+      t.integer('updated_at').alter()
     }),
-    knex.schema.table('passport', t => {
-      t.dropColumns('created_at', 'updated_at')
-      t.integer('created_at')
-      t.integer('updated_at')
+    knex.schema.alterTable('passport', t => {
+      t.integer('created_at').alter()
+      t.integer('updated_at').alter()
     }),
-    knex.schema.table('targeturl', t => {
-      t.dropColumns('created_at', 'updated_at')
-      t.integer('created_at')
-      t.integer('updated_at')
+    knex.schema.alterTable('targeturl', t => {
+      t.integer('created_at').alter()
+      t.integer('updated_at').alter()
     }),
-    knex.schema.table('book', t => {
-      t.dropColumns('created_at', 'updated_at')
-      t.integer('created_at')
-      t.integer('updated_at')
+    knex.schema.alterTable('book', t => {
+      t.integer('created_at').alter()
+      t.integer('updated_at').alter()
     })
   ])
 }