php - PDO Transaction inserting ? instead of value? -

Here's the snippet of code:

  $ pqry = $ dbcon- & gt; ("Include in Producer values ​​(tap, '?', '?', MD5 ('?'), MD5 ('?'))"); $ Dbcon- & gt; BeginTransaction (); $ Pqry- & gt; Execute (array ($ qryfields ['email'], $ qryfields ['pw'], $ qryfields ['pw'], $ qryfields ['pw'] time ()).); $ LastID = $ dbcon- & gt; Last InsertID (); $ Dbcon- & gt; Committed ();   
 Which row contains:  
 ? | ? | The value of the price? | <+>    
 Should I use the : key ?   
 
 
 You do not need quotes around placeholders:  
  $ Pqry = $ dbcon- & gt; Prepare ("Start pr_users VALUES (NULL, MD5, MD5)")? (?) (?);   
 Those PDOs think you're using string  '?' Instead of placeholder behavior  want to  
 This is a plain documentation, but it is quite clear from the examples.