diff --git a/backup.py b/backup.py
index 4a5ad57..f8266ee 100644
--- a/backup.py
+++ b/backup.py
@@ -1,18 +1,6 @@
 import sys
-from src import Database, FileSystem
 
-class Backup(FileSystem):
-    def __init__(self, argv):
-        super().__init__()
-        self.db = Database()
+from src import Backup
 
-    def backup(self, obj: list) -> bool:
-        db_response = self.db.check_obj(obj)
-        return True
-
-    def backup_all(self):
-        for item in self.all():
-            self.backup(item)
-
-Backup(sys.argv).backup_all()
+Backup().backup_all()
 print("OK")
\ No newline at end of file
diff --git a/src/__init__.py b/src/__init__.py
index c9d748d..5c467e0 100644
--- a/src/__init__.py
+++ b/src/__init__.py
@@ -3,6 +3,7 @@ from dotenv import load_dotenv
 from .glob import file_exists
 from .db import Database
 from .fs import FileSystem
+from .backup import Backup
 
 if not file_exists(".env"):
 	raise FileNotFoundError("Environment variable file does not exist. Copy '.env.example' to '.env'")
diff --git a/src/backup.py b/src/backup.py
new file mode 100644
index 0000000..ac2d259
--- /dev/null
+++ b/src/backup.py
@@ -0,0 +1,25 @@
+from typing import Union
+
+from . import Database, FileSystem
+
+class Backup(FileSystem):
+    def __init__(self):
+        super().__init__()
+        self.db = Database()
+
+    def backup_item(self, item: Union[list, str]) -> bool:
+        if isinstance(item, str):
+            item = self.get_item(item)
+
+        # Check item against db if it has changed
+        db_resp = self.db.check_item(item)
+        if not db_resp:
+            return True
+
+        self.db.set_item(item)
+        
+        return True
+
+    def backup_all(self):
+        for item in self.all():
+            self.backup_item(item)
\ No newline at end of file
diff --git a/src/db/config.sql b/src/db/config.sql
index 6b96c13..e0d4e63 100644
--- a/src/db/config.sql
+++ b/src/db/config.sql
@@ -11,6 +11,6 @@ CREATE TABLE manifest (
 
 INSERT INTO flags
 VALUES
-    ("CALC_CHECKSUM", 1),
+    ("ZIP", 1),
     ("BUCKET_OK", 0),
     ("INIT", 1);
\ No newline at end of file
diff --git a/src/db/database.py b/src/db/database.py
index c2afba3..9b61ff9 100644
--- a/src/db/database.py
+++ b/src/db/database.py
@@ -4,9 +4,27 @@ class Database(SQLite):
     def __init__(self):
         super().__init__()
 
-    # Test if a candidate item should be backed up
-    def check_item(self, obj: list) -> bool:
-        sql = f"SELECT anchor, mtime, chksum FROM manifest WHERE anchor = '{obj.anchor}'"
-        data = self.query(sql)
+    def item_exists(self, item: list) -> bool:
+        sql = f"SELECT anchor FROM manifest WHERE anchor = '{item[0]}'"
+        res = self.query(sql)
 
-        return True
\ No newline at end of file
+        return res
+
+    # Test if a candidate item should be backed up
+    def check_item(self, item: list) -> bool:
+        sql = f"SELECT anchor, mtime, chksum FROM manifest WHERE anchor = '{item[0]}'"
+        res = self.query(sql)
+        if not res:
+            return True
+
+        return res
+
+    # Insert or update item in database
+    def set_item(self, item: list) -> bool:
+        values = ",".join(item)
+        sql = f"INSERT INTO manifest (anchor, mtime, chksum) VALUES ({values})"
+        if not self.item_exists(item):
+            sql = f"UPDATE manifest SET anchor = '{item[0]}', mtime = '{item[1]}', chksum = '{item[2]}' WHERE anchor = '{item[0]}'"
+        res = self.query(sql)
+
+        return res
\ No newline at end of file
diff --git a/src/fs/fs.py b/src/fs/fs.py
index 8473d30..da74572 100644
--- a/src/fs/fs.py
+++ b/src/fs/fs.py
@@ -11,20 +11,22 @@ class FileSystem:
     def get_path() -> str:
         return os.getenv("SOURCE_FOLDER")
 
+    # Calculate a CRC32 checksum of provided data
     @staticmethod
     def chksum(data: str) -> str:
-        return zlib.crc32(data)
+        encoded = data.encode("utf-8")
+        return zlib.crc32(encoded)
 
     # Get metadata from candidate file or folder
-    def make_obj(self, anchor: str) -> list:
-        mtime = os.path.getmtime(anchor)
-        if os.path.isdir(anchor):
+    def get_item(self, path: list) -> list:
+        mtime = os.path.getmtime(path)
+        chksum = FileSystem.chksum(path + str(mtime))
 
+        data = [path, mtime, chksum]
+        return data
 
-        data = [anchor, mtime, chksum]
-        return obj
-
+    # Get all second-level files and folders for path
     def all(self) -> list:
-        content = os.listdir(self.path)
-        content = list(map(self.make_obj, content))
+        content = [os.path.join(self.path, f) for f in os.listdir(self.path)]
+        content = list(map(self.get_item, content))
         return content
\ No newline at end of file