diff --git a/src/lib/QueryHelper.ts b/src/lib/QueryHelper.ts
index 7586276..5970f70 100644
--- a/src/lib/QueryHelper.ts
+++ b/src/lib/QueryHelper.ts
@@ -68,9 +68,10 @@ export class QueryHelper {
     /**
      * Constructor.
      * @param pgPool
-     * @param tableCreationFile
+     * @param [tableCreationFile]
+     * @param [tableUpdateFile]
      */
-    constructor(pgPool: Pool, private tableCreationFile?: string) {
+    constructor(pgPool: Pool, private tableCreationFile?: string, private tableUpdateFile?: string) {
         this.pool = pgPool;
     }
 
@@ -85,6 +86,17 @@ export class QueryHelper {
         }
     }
 
+    /**
+     * Updates the definition of the tables if the table update file was passed in the constructor
+     */
+    public async updateTableDefinitions() {
+        if (this.tableUpdateFile) {
+            logger.info("Updating table definitions...");
+            const tableSql = await fsx.readFile(this.tableUpdateFile, "utf-8");
+            await this.query({text: tableSql});
+        }
+    }
+
     /**
      * executes the sql query with values and returns all results.
      * @param query
diff --git a/src/lib/dataaccess/DataObject.ts b/src/lib/dataaccess/DataObject.ts
index afabc32..1890425 100644
--- a/src/lib/dataaccess/DataObject.ts
+++ b/src/lib/dataaccess/DataObject.ts
@@ -1,4 +1,7 @@
-abstract class DataObject {
+/**
+ * abstact DataObject class
+ */
+export abstract class DataObject {
     protected dataLoaded: boolean = false;
 
     constructor(public id: number, protected row?: any) {
@@ -6,6 +9,9 @@ abstract class DataObject {
 
     protected abstract loadData(): Promise<void>;
 
+    /**
+     * Loads data from the database if data has not been loaded
+     */
     protected loadDataIfNotExists() {
         if (this.dataLoaded) {
             this.loadData();
diff --git a/src/lib/dataaccess/Post.ts b/src/lib/dataaccess/Post.ts
index 51c6b4c..b4193c4 100644
--- a/src/lib/dataaccess/Post.ts
+++ b/src/lib/dataaccess/Post.ts
@@ -1,4 +1,6 @@
-import {queryHelper, VoteType} from "./index";
+import {DataObject} from "./DataObject";
+import {queryHelper} from "./index";
+import dataaccess from "./index";
 import {User} from "./User";
 
 export class Post extends DataObject {
@@ -63,7 +65,7 @@ export class Post extends DataObject {
     /**
      * The type of vote the user performed on the post.
      */
-    public async userVote(userId: number): Promise<VoteType> {
+    public async userVote(userId: number): Promise<dataaccess.VoteType> {
         const result = await queryHelper.first({
             text: "SELECT vote_type FROM votes WHERE user_id = $1 AND item_id = $2",
             values: [userId, this.id],
diff --git a/src/lib/dataaccess/User.ts b/src/lib/dataaccess/User.ts
index ea7c7c9..bb680c4 100644
--- a/src/lib/dataaccess/User.ts
+++ b/src/lib/dataaccess/User.ts
@@ -1,3 +1,4 @@
+import {DataObject} from "./DataObject";
 import {queryHelper} from "./index";
 import {Post} from "./Post";
 
diff --git a/src/lib/dataaccess/index.ts b/src/lib/dataaccess/index.ts
index 8019329..1d610ef 100644
--- a/src/lib/dataaccess/index.ts
+++ b/src/lib/dataaccess/index.ts
@@ -4,7 +4,9 @@ import {QueryHelper} from "../QueryHelper";
 import {User} from "./User";
 
 const config = globals.config;
-const tableCreationFile = __dirname + "/../sql/create-tables.sql";
+const tableCreationFile = __dirname + "/../../sql/create-tables.sql";
+const tableUpdateFile = __dirname + "/../../sql/update-tables.sql";
+
 const dbClient: Pool = new Pool({
     database: config.database.database,
     host: config.database.host,
@@ -12,13 +14,14 @@ const dbClient: Pool = new Pool({
     port: config.database.port,
     user: config.database.user,
 });
-export const queryHelper = new QueryHelper(dbClient, tableCreationFile);
+export const queryHelper = new QueryHelper(dbClient, tableCreationFile, tableUpdateFile);
 
 namespace dataaccess {
     /**
      * Initializes everything that needs to be initialized asynchronous.
      */
     export async function init() {
+        await queryHelper.updateTableDefinitions();
         await queryHelper.createTables();
     }
 
diff --git a/src/sql/create-tables.sql b/src/sql/create-tables.sql
index 7a6292e..7c1c97a 100644
--- a/src/sql/create-tables.sql
+++ b/src/sql/create-tables.sql
@@ -21,7 +21,7 @@ CREATE TABLE IF NOT EXISTS posts (
 CREATE TABLE IF NOT EXISTS votes (
     user_id SERIAL REFERENCES users (id) ON DELETE CASCADE,
     item_id BIGSERIAL REFERENCES posts (id) ON DELETE CASCADE,
-    vote_type varchar(8) DEFAULT 1
+    vote_type varchar(8) DEFAULT 'upvote'
 );
 
 CREATE TABLE IF NOT EXISTS events (
diff --git a/src/sql/update-tables.sql b/src/sql/update-tables.sql
new file mode 100644
index 0000000..52ce2f6
--- /dev/null
+++ b/src/sql/update-tables.sql
@@ -0,0 +1,3 @@
+ALTER TABLE IF EXISTS votes
+    ADD COLUMN IF NOT EXISTS vote_type varchar(8) DEFAULT 'upvote',
+    ALTER COLUMN vote_type SET DEFAULT 'upvote';