diff --git a/src/lib/dataaccess/User.ts b/src/lib/dataaccess/User.ts
index b29dfcc..6358e59 100644
--- a/src/lib/dataaccess/User.ts
+++ b/src/lib/dataaccess/User.ts
@@ -61,6 +61,25 @@ export class User extends DataObject {
         return new Date(this.$joinedAt);
     }
 
+    /**
+     * Returns all friends of the user.
+     */
+    public async friends(): Promise<User[]> {
+        const result = await queryHelper.all({
+            text: "SELECT * FROM user_friends WHERE user_id = $1 OR friend_id = $1",
+            values: [this.id],
+        });
+        const userFriends = [];
+        for (const row of result) {
+            if (row.user_id === this.id) {
+                userFriends.push(new User(row.friend_id));
+            } else {
+                userFriends.push(new User(row.user_id));
+            }
+        }
+        return userFriends;
+    }
+
     /**
      * Returns all posts for a user.
      */
diff --git a/src/lib/dataaccess/index.ts b/src/lib/dataaccess/index.ts
index 3db84ab..922fdac 100644
--- a/src/lib/dataaccess/index.ts
+++ b/src/lib/dataaccess/index.ts
@@ -41,8 +41,8 @@ namespace dataaccess {
      * Initializes everything that needs to be initialized asynchronous.
      */
     export async function init() {
-        await queryHelper.updateTableDefinitions();
         await queryHelper.createTables();
+        await queryHelper.updateTableDefinitions();
     }
 
     /**
diff --git a/src/routes/home.ts b/src/routes/home.ts
index cd9fec9..0ce10ad 100644
--- a/src/routes/home.ts
+++ b/src/routes/home.ts
@@ -135,7 +135,7 @@ class HomeRoute extends Route {
                         return await (new Post(postId)).vote(req.session.userId, type);
                     } else {
                         res.status(status.UNAUTHORIZED);
-                        return new GraphQLError("Not logged in.");
+                        return new NotLoggedInGqlError();
                     }
                 } else {
                     res.status(status.BAD_REQUEST);
@@ -148,7 +148,7 @@ class HomeRoute extends Route {
                         return await dataaccess.createPost(content, req.session.userId);
                     } else {
                         res.status(status.UNAUTHORIZED);
-                        return new GraphQLError("Not logged in.");
+                        return new NotLoggedInGqlError();
                     }
                 } else {
                     res.status(status.BAD_REQUEST);
diff --git a/src/sql/create-tables.sql b/src/sql/create-tables.sql
index 17f6e74..a1563ac 100644
--- a/src/sql/create-tables.sql
+++ b/src/sql/create-tables.sql
@@ -1,65 +1,125 @@
-CREATE TABLE IF NOT EXISTS "user_sessions" (
-    "sid" varchar NOT NULL COLLATE "default",
-    "sess" json NOT NULL,
-	"expire" timestamp(6) NOT NULL,
-	PRIMARY KEY ("sid") NOT DEFERRABLE INITIALLY IMMEDIATE
-) WITH (OIDS=FALSE);
-
-CREATE TABLE IF NOT EXISTS users (
-    id SERIAL PRIMARY KEY,
-    name varchar(128) NOT NULL,
-    handle varchar(128) UNIQUE NOT NULL,
-    password varchar(1024) NOT NULL,
-    email varchar(128) UNIQUE NOT NULL,
-    greenpoints INTEGER DEFAULT 0,
-    joined_at TIMESTAMP DEFAULT now()
-);
-
-CREATE TABLE IF NOT EXISTS posts (
-    id BIGSERIAL PRIMARY KEY,
-    upvotes INTEGER DEFAULT 0,
-    downvotes INTEGER DEFAULT 0,
-    created_at TIMESTAMP DEFAULT now(),
-    content text,
-    author SERIAL REFERENCES users (id) ON DELETE CASCADE,
-    type varchar(16) NOT NULL DEFAULT 'MISC'
-);
-
-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 'upvote'
-);
-
-CREATE TABLE IF NOT EXISTS events (
-    id BIGSERIAL PRIMARY KEY,
-    time TIMESTAMP,
-    owner SERIAL REFERENCES users (id)
-);
-
-CREATE TABLE IF NOT EXISTS event_members (
-    event BIGSERIAL REFERENCES events (id),
-    member SERIAL REFERENCES users (id)
-);
-
-CREATE TABLE IF NOT EXISTS chats (
-    id BIGSERIAL PRIMARY KEY
-);
-
-CREATE TABLE IF NOT EXISTS chat_messages (
-    chat BIGSERIAL REFERENCES chats (id) ON DELETE CASCADE,
-    author SERIAL REFERENCES users (id) ON DELETE SET NULL,
-    content VARCHAR(1024) NOT NULL,
-    created_at TIMESTAMP DEFAULT now(),
-    PRIMARY KEY (chat, author, created_at)
-);
-
-CREATE TABLE IF NOT EXISTS chat_members (
-    chat BIGSERIAL REFERENCES chats (id) ON DELETE CASCADE,
-    member SERIAL REFERENCES users (id) ON DELETE CASCADE
-);
-
-CREATE TABLE IF NOT EXISTS user_friends (
-    user_id SERIAL REFERENCES users (id) ON DELETE CASCADE,
-    friend_id SERIAL REFERENCES users (id) ON DELETE CASCADE
-);
+--create functions
+DO $$BEGIN
+
+    IF NOT EXISTS(SELECT 1 from pg_proc WHERE proname = 'function_exists') THEN
+        CREATE FUNCTION function_exists(text) RETURNS boolean LANGUAGE plpgsql AS $BODY$
+        BEGIN
+            RETURN EXISTS(SELECT 1 from pg_proc WHERE proname = $1);
+        END $BODY$;
+    END IF;
+
+    IF NOT function_exists('type_exists') THEN
+        CREATE FUNCTION type_exists(text) RETURNS boolean LANGUAGE plpgsql AS $BODY$
+        BEGIN
+            RETURN EXISTS (SELECT 1 FROM pg_type WHERE typname = $1);
+        END $BODY$;
+    END IF;
+
+    IF NOT function_exists('cast_to_votetype') THEN
+        CREATE FUNCTION cast_to_votetype(text) RETURNS votetype LANGUAGE plpgsql AS $BODY$
+        BEGIN
+            RETURN CASE WHEN $1::votetype IS NULL THEN 'UPVOTE' ELSE $1::votetype END;
+        END $BODY$;
+    END IF;
+
+    IF NOT function_exists('cast_to_posttype') THEN
+        CREATE FUNCTION cast_to_posttype(text) RETURNS posttype LANGUAGE plpgsql AS $BODY$
+        BEGIN
+            RETURN CASE WHEN $1::posttype IS NULL THEN 'MISC' ELSE $1::posttype END;
+        END $BODY$;
+    END IF;
+
+END$$;
+
+--create types
+DO $$ BEGIN
+
+    IF NOT type_exists('votetype') THEN
+        CREATE TYPE votetype AS enum ('DOWNVOTE', 'UPVOTE');
+    END IF;
+
+    IF NOT type_exists('posttype') THEN
+        CREATE TYPE posttype AS enum ('MISC', 'ACTION', 'IMAGE', 'TEXT');
+    END IF;
+
+    IF NOT type_exists('requesttype') THEN
+        CREATE TYPE requesttype AS enum ('FRIENDREQUEST');
+    END IF;
+
+END$$;
+
+-- create tables
+DO $$ BEGIN
+
+    CREATE TABLE IF NOT EXISTS "user_sessions" (
+        "sid" varchar NOT NULL COLLATE "default",
+        "sess" json NOT NULL,
+        "expire" timestamp(6) NOT NULL,
+        PRIMARY KEY ("sid") NOT DEFERRABLE INITIALLY IMMEDIATE
+    ) WITH (OIDS=FALSE);
+
+    CREATE TABLE IF NOT EXISTS users (
+        id SERIAL PRIMARY KEY,
+        name varchar(128) NOT NULL,
+        handle varchar(128) UNIQUE NOT NULL,
+        password varchar(1024) NOT NULL,
+        email varchar(128) UNIQUE NOT NULL,
+        greenpoints INTEGER DEFAULT 0,
+        joined_at TIMESTAMP DEFAULT now()
+    );
+
+    CREATE TABLE IF NOT EXISTS posts (
+        id BIGSERIAL PRIMARY KEY,
+        upvotes INTEGER DEFAULT 0,
+        downvotes INTEGER DEFAULT 0,
+        created_at TIMESTAMP DEFAULT now(),
+        content text,
+        author SERIAL REFERENCES users (id) ON DELETE CASCADE,
+        type posttype NOT NULL DEFAULT 'MISC'
+    );
+
+    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 votetype DEFAULT 'DOWNVOTE'
+    );
+
+    CREATE TABLE IF NOT EXISTS events (
+        id BIGSERIAL PRIMARY KEY,
+        time TIMESTAMP,
+        owner SERIAL REFERENCES users (id)
+    );
+
+    CREATE TABLE IF NOT EXISTS event_members (
+        event BIGSERIAL REFERENCES events (id),
+        member SERIAL REFERENCES users (id)
+    );
+
+    CREATE TABLE IF NOT EXISTS chats (
+        id BIGSERIAL PRIMARY KEY
+    );
+
+    CREATE TABLE IF NOT EXISTS chat_messages (
+        chat BIGSERIAL REFERENCES chats (id) ON DELETE CASCADE,
+        author SERIAL REFERENCES users (id) ON DELETE SET NULL,
+        content VARCHAR(1024) NOT NULL,
+        created_at TIMESTAMP DEFAULT now(),
+        PRIMARY KEY (chat, author, created_at)
+    );
+
+    CREATE TABLE IF NOT EXISTS chat_members (
+        chat BIGSERIAL REFERENCES chats (id) ON DELETE CASCADE,
+        member SERIAL REFERENCES users (id) ON DELETE CASCADE
+    );
+
+    CREATE TABLE IF NOT EXISTS user_friends (
+        user_id SERIAL REFERENCES users (id) ON DELETE CASCADE,
+        friend_id SERIAL REFERENCES users (id) ON DELETE CASCADE
+    );
+
+    CREATE TABLE IF NOT EXISTS requests (
+        sender SERIAL REFERENCES users (id) ON DELETE CASCADE,
+        receiver SERIAL REFERENCES users (id) ON DELETE CASCADE
+    );
+
+END $$;
diff --git a/src/sql/update-tables.sql b/src/sql/update-tables.sql
index 13bc681..da794c7 100644
--- a/src/sql/update-tables.sql
+++ b/src/sql/update-tables.sql
@@ -1,8 +1,16 @@
-ALTER TABLE IF EXISTS votes
-    ADD COLUMN IF NOT EXISTS vote_type varchar(8) DEFAULT 'UPVOTE',
-    ALTER COLUMN vote_type SET DEFAULT 'UPVOTE';
+DO $$ BEGIN
 
-ALTER TABLE IF EXISTS posts
-    ALTER COLUMN type SET DEFAULT 'MISC',
-    DROP COLUMN IF EXISTS upvotes,
-    DROP COLUMN IF EXISTS downvotes;
+    ALTER TABLE IF EXISTS votes
+        ADD COLUMN IF NOT EXISTS vote_type votetype DEFAULT 'UPVOTE',
+        ALTER COLUMN vote_type TYPE votetype USING cast_to_votetype(vote_type::text),
+        ALTER COLUMN vote_type DROP DEFAULT,
+        ALTER COLUMN vote_type SET DEFAULT 'UPVOTE';
+
+    ALTER TABLE IF EXISTS posts
+        ALTER COLUMN type TYPE posttype USING cast_to_posttype(type::text),
+        ALTER COLUMN type DROP DEFAULT,
+        ALTER COLUMN type SET DEFAULT 'MISC',
+        DROP COLUMN IF EXISTS upvotes,
+        DROP COLUMN IF EXISTS downvotes;
+
+END $$;