diff --git a/slack_backup/db.py b/slack_backup/db.py
new file mode 100644
index 0000000..ca26e06
--- /dev/null
+++ b/slack_backup/db.py
@@ -0,0 +1,34 @@
+"""
+Common db functions
+"""
+from sqlalchemy import MetaData, create_engine
+from sqlalchemy.orm import sessionmaker
+from sqlalchemy.ext.declarative import declarative_base
+
+
+# Prepare SQLAlchemy objects
+Meta = MetaData()
+Base = declarative_base(metadata=Meta)
+Session = sessionmaker()
+DbFilename = None
+
+
+def connect(filename=None):
+    """
+    create engine and bind to Meta object.
+    Arguments:
+        @filename - string with absolute or relative path to sqlite database
+                    file. If None, db in-memory will be created
+    """
+    global DbFilename
+
+    if not filename:
+        filename = ':memory:'
+
+    DbFilename = filename
+
+    connect_string = "sqlite:///%s" % filename
+    engine = create_engine(connect_string)
+    Meta.bind = engine
+    Meta.create_all(checkfirst=True)
+    return engine