diff --git a/manage_db.py b/manage_db.py
index 222bf70..53ebb38 100644
--- a/manage_db.py
+++ b/manage_db.py
@@ -4,6 +4,11 @@ import sqlite3
 import fcntl
 import uuid
 
+from utilities.constants import APIKEY
+from utilities.constants import UUID
+from utilities.constants import USERS_TABLE_NAME
+from utilities.constants import HISTORY_TABLE_NAME
+
 
 # Function to acquire a lock on the database file
 def acquire_lock(lock_file):
@@ -21,15 +26,15 @@ def release_lock(lock_file):
 USERS_TABLE_COLUMNS = [
     "id INTEGER PRIMARY KEY AUTOINCREMENT",
     "username TEXT UNIQUE",
-    "apikey TEXT",
+    f"{APIKEY} TEXT",
     "quota INT DEFAULT 50",
 ]
 
 HISTORY_TABLE_COLUMNS = [
-    "uuid TEXT PRIMARY KEY",
+    f"{UUID} TEXT PRIMARY KEY",
     "created_at TIMESTAMP",
     "updated_at TIMESTAMP",
-    "apikey TEXT",
+    f"{APIKEY} TEXT",
     "priority INT",
     "type TEXT",
     "status TEXT",
@@ -58,9 +63,9 @@ def create_or_update_table(c, table_name):
     )
     existing_table = c.fetchone()
 
-    if table_name == "users":
+    if table_name == USERS_TABLE_NAME:
         target_columns = USERS_TABLE_COLUMNS
-    elif table_name == "history":
+    elif table_name == HISTORY_TABLE_NAME:
         target_columns = HISTORY_TABLE_COLUMNS
     else:
         target_columns = []
@@ -109,47 +114,59 @@ def modify_table(c, table_name, operation, column_name=None, data_type=None):
 
 def create_user(c, username, apikey):
     """Create a user with the given username and apikey, or update the apikey if the username already exists"""
-    c.execute("SELECT * FROM users WHERE username=?", (username,))
+    c.execute(f"SELECT * FROM {USERS_TABLE_NAME} WHERE username=?", (username,))
     result = c.fetchone()
     if result is not None:
         raise ValueError(f"found exisitng user {username}, please use update")
     else:
         c.execute(
-            "INSERT INTO users (username, apikey) VALUES (?, ?)", (username, apikey)
+            f"INSERT INTO {USERS_TABLE_NAME} (username, {APIKEY}) VALUES (?, ?)",
+            (username, apikey),
         )
 
 
 def update_user(c, username, apikey):
     """Update the apikey for the user with the given username"""
-    c.execute("SELECT apikey FROM users WHERE username=?", (username,))
+    c.execute(f"SELECT {APIKEY} FROM {USERS_TABLE_NAME} WHERE username=?", (username,))
     result = c.fetchone()
     if result is not None:
         old_apikey = result[0]
-        c.execute("UPDATE history SET apikey=? WHERE apikey=?", (apikey, old_apikey))
-        c.execute("UPDATE users SET apikey=? WHERE username=?", (apikey, username))
+        c.execute(
+            f"UPDATE {HISTORY_TABLE_NAME} SET {APIKEY}=? WHERE {APIKEY}=?",
+            (apikey, old_apikey),
+        )
+        c.execute(
+            f"UPDATE {USERS_TABLE_NAME} SET {APIKEY}=? WHERE username=?",
+            (apikey, username),
+        )
     else:
         raise ValueError("username does not exist! create it first?")
 
 
 def update_quota(c, apikey, quota):
-    c.execute("SELECT username FROM users WHERE apikey=?", (apikey,))
+    c.execute(f"SELECT username FROM {USERS_TABLE_NAME} WHERE {APIKEY}=?", (apikey,))
     result = c.fetchone()
     if result is not None:
-        c.execute("UPDATE users SET quota=? WHERE apikey=?", (quota, apikey))
+        c.execute(
+            f"UPDATE {USERS_TABLE_NAME} SET quota=? WHERE {APIKEY}=?", (quota, apikey)
+        )
     raise ValueError(f"{apikey} does not exist")
 
 
 def update_username(c, apikey, username):
-    c.execute("SELECT username FROM users WHERE apikey=?", (apikey,))
+    c.execute(f"SELECT username FROM {USERS_TABLE_NAME} WHERE {APIKEY}=?", (apikey,))
     result = c.fetchone()
     if result is not None:
-        c.execute("UPDATE users SET username=? WHERE apikey=?", (username, apikey))
+        c.execute(
+            f"UPDATE {USERS_TABLE_NAME} SET username=? WHERE {APIKEY}=?",
+            (username, apikey),
+        )
 
 
 def delete_user(c, username):
     """Delete the user with the given username, or ignore the operation if the user does not exist"""
     delete_jobs(c, username=username)
-    c.execute("DELETE FROM users WHERE username=?", (username,))
+    c.execute(f"DELETE FROM {USERS_TABLE_NAME} WHERE username=?", (username,))
     print(f"removed {c.rowcount} entries")
 
 
@@ -157,7 +174,7 @@ def delete_jobs(c, job_uuid="", username=""):
     """Delete the job with the given uuid, or ignore the operation if the uuid does not exist"""
     if username:
         c.execute(
-            "SELECT img, ref_img, mask_img FROM history WHERE apikey=(SELECT apikey FROM users WHERE username=?)",
+            f"SELECT img, ref_img, mask_img FROM {HISTORY_TABLE_NAME} WHERE apikey=(SELECT {APIKEY} FROM {USERS_TABLE_NAME} WHERE username=?)",
             (username,),
         )
         rows = c.fetchall()
@@ -175,13 +192,13 @@ def delete_jobs(c, job_uuid="", username=""):
                     print(f"failed to remove {filepath}")
                     raise
         c.execute(
-            "DELETE FROM history WHERE apikey=(SELECT apikey FROM users WHERE username=?)",
+            f"DELETE FROM {HISTORY_TABLE_NAME} WHERE {APIKEY}=(SELECT {APIKEY} FROM {USERS_TABLE_NAME} WHERE username=?)",
             (username,),
         )
         print(f"removed {c.rowcount} entries")
     elif job_uuid:
         c.execute(
-            "SELECT img, ref_img, mask_img FROM history WHERE uuid=?",
+            f"SELECT img, ref_img, mask_img FROM {HISTORY_TABLE_NAME} WHERE uuid=?",
             (job_uuid,),
         )
         result = c.fetchone()
@@ -197,7 +214,7 @@ def delete_jobs(c, job_uuid="", username=""):
                 print(f"failed to remove {filepath}")
                 raise
         c.execute(
-            "DELETE FROM history WHERE uuid=?",
+            f"DELETE FROM {HISTORY_TABLE_NAME} WHERE uuid=?",
             (job_uuid,),
         )
         print(f"removed {c.rowcount} entries")
@@ -207,15 +224,21 @@ def show_users(c, username="", details=False):
     """Print all users in the users table if username is not specified,
     or only the user with the given username otherwise"""
     if username:
-        c.execute("SELECT username, apikey FROM users WHERE username=?", (username,))
+        c.execute(
+            f"SELECT username, {APIKEY} FROM {USERS_TABLE_NAME} WHERE username=?",
+            (username,),
+        )
         user = c.fetchone()
         if user:
-            c.execute("SELECT COUNT(*) FROM history WHERE apikey=?", (user[1],))
+            c.execute(
+                f"SELECT COUNT(*) FROM {HISTORY_TABLE_NAME} WHERE {APIKEY}=?",
+                (user[1],),
+            )
             count = c.fetchone()[0]
             print(f"Username: {user[0]}, API Key: {user[1]}, Number of jobs: {count}")
             if details:
                 c.execute(
-                    "SELECT uuid, created_at, updated_at, type, status, width, height, steps, img, ref_img, mask_img, is_private FROM history WHERE apikey=?",
+                    f"SELECT {UUID}, created_at, updated_at, type, status, width, height, steps, img, ref_img, mask_img, is_private FROM {HISTORY_TABLE_NAME} WHERE apikey=?",
                     (user[1],),
                 )
                 rows = c.fetchall()
@@ -224,15 +247,18 @@ def show_users(c, username="", details=False):
         else:
             print(f"No user with username '{username}' found")
     else:
-        c.execute("SELECT username, apikey FROM users")
+        c.execute(f"SELECT username, {APIKEY} FROM {USERS_TABLE_NAME}")
         users = c.fetchall()
         for user in users:
-            c.execute("SELECT COUNT(*) FROM history WHERE apikey=?", (user[1],))
+            c.execute(
+                f"SELECT COUNT(*) FROM {HISTORY_TABLE_NAME} WHERE {APIKEY}=?",
+                (user[1],),
+            )
             count = c.fetchone()[0]
             print(f"Username: {user[0]}, API Key: {user[1]}, Number of jobs: {count}")
             if details:
                 c.execute(
-                    "SELECT * FROM history WHERE apikey=?",
+                    f"SELECT * FROM {HISTORY_TABLE_NAME} WHERE {APIKEY}=?",
                     (user[1],),
                 )
                 rows = c.fetchall()
@@ -260,8 +286,8 @@ def manage(args):
         c = conn.cursor()
 
         # Create the users and history tables if they don't exist
-        create_or_update_table(c, "users")
-        create_or_update_table(c, "history")
+        create_or_update_table(c, USERS_TABLE_NAME)
+        create_or_update_table(c, HISTORY_TABLE_NAME)
 
         # Perform the requested action
         if args.action == "create":