diff --git a/android_db.py b/android_db.py
index 50ae2dc..e97e233 100644
--- a/android_db.py
+++ b/android_db.py
@@ -3,9 +3,8 @@ import re
 import csv
 import sys
 csv.field_size_limit(2**31-1)
-param_str = re.compile(r'(?<=\()[ ,\?]+(?=\))')
-validator = re.compile(r'^\?(?: *\, *\?)*$')
-param_sep = re.compile(r' *\, *')
+dict_params = re.compile(r':([^\ \,\.\\\(\)\=]+)')
+list_params = re.compile(r'\?')
 class AndroidSQLConn:
     def __init__(self,device,filepath,use_root=True):
         self.device = device
@@ -22,21 +21,24 @@ class AndroidSQLConn:
         else:
             return str(param)
     def _sub_params_(SQL,params):
-        p_string = param_str.search(SQL).group(0)
-        if not validator.match(p_string):
-            raise ValueError('Invalid substitution')
+        params = iter(params)
+        try:
+            return list_params.sub(lambda match: AndroidSQLConn._quote_param_(next(params)),SQL)
+        except StopIteration:
+            raise TypeError("Not enough parameters")
+
+    def _sub_params_dict_(SQL,params):
+        try:
+            return dict_params.sub(lambda match: AndroidSQLConn._quote_param_(params[match.group(1)]),SQL)
+        except KeyError:
+            raise TypeError("Parameter specified but not in mapping")
 
-        n_params = len(param_sep.split(p_string))
-        if len(params) < n_params:
-            raise ValueError('Not enough parameters supplied')
-        new_str = ','.join(map(
-            AndroidSQLConn._quote_param_,params[:n_params]
-            ))
-        print(*map(repr,(new_str,SQL)))
-        return param_str.sub(re.escape(new_str),SQL,1)
     def execute(self,SQL,params = None):
         if params:
-            SQL = AndroidSQLConn._sub_params_(SQL,params)
+            if isinstance(params,dict):
+                SQL = AndroidSQLConn._sub_params_dict_(SQL,params)
+            else:
+                SQL = AndroidSQLConn._sub_params_(SQL,params)
         SQL = shlex.quote(SQL)
         if self.root:
             shell = self.device.sudo
@@ -45,3 +47,6 @@ class AndroidSQLConn:
         out = shell('sqlite3','-header','-csv',shlex.quote(self.filepath),SQL,output="out")
         if out:
             return csv.DictReader(out.splitlines())
+
+if __name__ == "__main__":
+    print(AndroidSQLConn._sub_params_("SELECT * FROM table WHERE name=?,age=?;",["boby;DROP TABLE table",1]))
\ No newline at end of file