diff --git a/src/obindex.py b/src/obindex.py
index f534b21..fde7599 100644
--- a/src/obindex.py
+++ b/src/obindex.py
@@ -167,23 +167,23 @@ if __name__ == '__main__':
         
         c = db.execute("""
                        insert into sequence (id,forward,reverse)
-                       values (%d,'%s','%s');
-                       """ % (seqid,tseq[0],tseq[1]))
+                       values (?,?,?);
+                       """ ,(seqid,tseq[0],tseq[1]))
         
         db.commit()
         
         for w in words:
             try:
-                c = db.execute("""select id from words where word='%s';""" % w)
+                c = db.execute("""select id from words where word=?;""" , (w,))
                 wid = c.fetchone()["id"]
             except :
                 db.rollback()
                 wid = wordid
-                c = db.execute("""insert into words (id,word) values (%d,'%s') ;""" % (wid,w))
+                c = db.execute("""insert into words (id,word) values (?,?) ;""" , (wid,w))
                 wordid+=1
 
                 
-            c = db.execute(""" insert into composition (seqid,wordid) values (%d,%d) ;""" % (seqid,wid))
+            c = db.execute(""" insert into composition (seqid,wordid) values (?,?) ;""" , (seqid,wid))
                             
             db.commit()