obsdb: Add func _get_positions()

ols/obsdb.py

@@ -270,6 +270,14 @@ class ObservationDB(ObservationDBBase):
             """)
         return [t[0] for t in timestamps.fetchall()]
 
+    def _get_positions(self):
+        """Return a list of all rows in observation table."""
+        cur = self.con.cursor()
+        locations = cur.execute("""
+            SELECT * FROM observations;
+            """).fetchall()
+        return [{k: loc[k] for k in loc.keys()} for loc in locations]
+
     def remove(self, timestamp):
         """Remove an observation and its associated wifi, cell and bt rows."""
         cur = self.con.cursor()