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POphp mysql pdo auction bidding
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copied!<p>I am developing an auction system with a limit or max bid scenario using php mySQL(MyISAM) and PDO, using two tables </p> <p><strong>auction</strong></p> <pre><code> Id | title | seller | currentbid | limit(max bid) | dated | bidder </code></pre> <p><strong>bids</strong></p> <pre><code> Id | auctionid | bid | bidder | dated </code></pre> <p>After user placed a bid the following happens (I am using PDO prepared statements)</p> <pre><code> $record = fetch (‘Select * from auction where id = :id’, array(‘id’ => $id)) $increment = 1; $postedBid = $_REQUEST[‘postedBid’]; $currentBid = $record[‘currentbid’]; $limitBid = $record[‘limit’]; If($postedBid < $currentBid + $increment){ Return;(without processing bid!) }else{ If($limitBid !> $postedBid){ Insert into bids (auctionid, bid, bidder, dated(timestamp)) values ($auctioned, $postedBid, ……); Update auction set currentbid = $postedBid, limit = $postedBid …. }else{ Insert into bids (auctionid, bid, bidder, dated(timestamp)) values ($auctioned, $postedBid, ……); Insert into bids (auctionid, bid, bidder, dated(timestamp)) values ($auctioned, $postedBid + $increment, ……); Update auction set currentbid = $postedBid + increment, limit = $limitBid …. } } </code></pre> <p>i want to know two things</p> <p>1- if this approach is ok and how can I improve this</p> <p>2- How can I avoid concurrent bids. I don’t know how to apply locks using PDO. Appreciate any example queries using locks or any other approach to deal with this problem</p> <p>Thanks </p> <p>(Apologies for using mixed type of code)</p>

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