制作我们自己的Ebay拍卖系统6 -pc6资讯

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制作我们自己的Ebay拍卖系统6 时间：2004/11/7 2:52:00来源：本站整理作者：蓝点我要评论(0): Resolving Bids - Page 6

Chris Payne

September 11, 2000

Function ResolveBids(ItemID)

'Set variables and create objects

dim monIncrement, monHighPrice, intAvailable, intTotItems, flgQuit

dim blnResolved

'Assume bids are resolved

blnResolved = True

strConnectionString = "DSN=MyAuction;UID=username;PWD=password;Database=MyAuctionDB"

set rst = Server.CreateObject("ADODB.Recordset")

'Get information from items table

strSQL = "SELECT Increment, Available FROM tblAuctionItems WHERE " & _

　　"IID = " & ItemID

rst.open strSQL, strConnectionString

monIncrement = rst(0)

intAvailable = rst(1)

rst.close

'Find the highest bid and total number items bid for

strSQL = "SELECT max(WinPrice) AS WinPrice, sum(WinItems) as " & _

　　"WinItems FROM tblAuctionBids WHERE " & _

　　"ItemID = " & ItemID

rst.open strSQL, strConnectionString

monHighPrice = rst(0)

intTotItems = rst(1)

rst.close

'If a user with a higher max bid exists, then

' update their bid if and only if available items is exceeded

strSQL = "SELECT MaxBid, UID, BidItems, WinPrice FROM " & _

　　"tblAuctionBids WHERE ItemID = " & ItemID

rst.open strSQL, strConnectionString

if not rst.eof then

　　do until rst.eof

　　　　if (rst(0) > monHighPrice + monIncrement) AND (intTotItems > intAvailable) & _

　　　　　　AND (rst(3) <> monHighPrice) then

　　　　　　monHighPrice = monHighPrice + monIncrement

　　　　　　call DoBids(ItemID, rst(1), monHighPrice)

　　　　　　blnResolved = False

　　　　end if

　　　　rst.MoveNext

　　　　'If we're at the end of the recordset

　　　　and the bids are not yet resolved, go back to the beginning

　　　　if not blnResolved AND rst.eof then

　　　　　　rst.MoveFirst

　　　　　　blnResolved = True

　　　　end if

　　loop

end if

rst.close

End Function

The main part of the above code is the last do...loop section. The process is as follows:

Enter a user's bid (using the DoBids() function)

Find the highest bid for the item, and total number of items bid for

Loop through database and:

IF the current bidder's maximum bid is higher than the highest winning bid,

AND the total number of items bid for is greater than the number of items available,

AND the current bidder's bid is not the highest bid,

THEN increment the current bidder's bid by the increment value.

If we reach the end of the recordset, and the bids are still not resolved, the start over.

This process will automatically update all bids appropriately, and weed out those whose max bids are not

high enough. The reason we check to make sure the total number of items bid for is greater than the number

of total items available in step 4 is because if all bids are placed and items claimed, and there are

still lots available, then everyone wins and bids do not need to be incremented.

For example, imagine there are 10 lots available, and there are 3 bidders. If bidder A wants 3 lots at $3,

bidder B wants 3 lots at $2, and bidder C wants 3 lots at $1, everyone will win because there is enough

lots to go around, and then some. The do loop above will only have to go through once.

However, suppose bidder C now wants 5 items. Since there are not enough items to go around, someone will

have to lose out. The loop in the code above weeds this person out by checking max bids and updating the

winning bids. If everyone's max bids in this scenario was $20, and the increment was $2, then bidder C and

whichever of bidder A and B placed the first bid would win (remember that bid priority is placed on most

lots bid for, followed by bid time).

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