Dealing with the presence of an XML tag rather than the data within the tag

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Dealing with the presence of an XML tag rather than the data within the tag

MarksmanWaugh

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Points: 300
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May 19, 2008 at 8:20 am

#190624

I'm having a head banging moment where I am sure the answer is painfully obvious but I just can't seem to get there. First, some context:
Retail Transaction log in XML being sucked into an SQL Server 2005 database. At it's simplest the TLog looks something like:
[PointOfSale]
[Contents]
[TLOG]
[Transactions]
[Transaction]
[Items]
...
[/Items]
[Tenders]
...
[/Tenders]
[Customer]
...
[/Customer]
[/Transaction]
[/Transactions]
[/TLOG]
[/Contents]
[/PointOfSale]
Following I have a code snippet to check starting at an expected node and building what is my transaction header table; essentially specific information pertaining to the transaction. I'm not having any problems doing this when the start and end tags each have data within them.
DECLARE @iDoc INT
DECLARE @xmlDoc XML
SET @xmlDoc = (SELECT * FROM OPENROWSET ( BULK 'C:\tlog.xml', SINGLE_CLOB ) AS xmlData)
--Prepare the XML Document by executing a system stored procedure
EXEC SP_XML_PREPAREDOCUMENT @iDoc OUTPUT, @xmlDoc
-- INSERT stmt for header table
INSERT INTO [Header_Table]
(
[Type],TrxID,Date,Register,[User],Store,Charges,Taxes,Tenders,CustID,LName,FName
)
-- SELECT stmt using OPENXML rowset provider
SELECT * FROM OPENXML (@iDoc, '/PointOfSale/Contents/TLOG/Transactions/Transaction',2)
WITH([Type] VARCHAR(6),
[GUID] VARCHAR(25),
Date DATETIME,
RegisterCode VARCHAR(6),
[User] BIGINT,
StoreUID VARCHAR(6),
Charges MONEY,
Taxes MONEY,
Tenders MONEY,
SyncID VARCHAR(25) 'Customer/SyncID',
NameLast VARCHAR(25) 'Customer/NameLast',
NameFirst VARCHAR(25) 'Customer/NameFirst'
)
WHERE NOT EXISTS (SELECT * FROM [Header_Table] WHERE TrxID = [GUID])
-- Free up the memory used by the XML document.
EXEC SP_XML_REMOVEDOCUMENT @iDoc
My problem starts when I have tags with no data; in fact ending tags with no start tags and no data. It looks like this:
...
[IsPostVoid /]
[Transaction]
[Items]
...
[/Items]
[Tenders]
...
[/Tenders]
[Customer]
...
[/Customer]
[/Transaction]
...
The presence of the tag [IsPostVoid /] denotes this is a void transaction, so I need to record into some field the transaction "Mode" if you like. I'll create a new field on my [Header_Table] and call it Mode and would like to store in this field the word "Post Void" if [IsPostVoid /] exists in a transaction.
I'm stumped though. Ideas? Thank you in advance!

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Mark Cowne One Orange Chip Points: 26944 More actions · Answer 1

See if this helps - the convoluted xquery below gets the name of the previous element

Note that if you are using SQL Server 2005, you may find it easier to use the "nodes" syntax.

DECLARE @xmlDoc XML

SET @xmlDoc='

[PointOfSale]

[Contents]

[TLOG]

[Transactions]

[Transaction]

[Items]I1[/Items]

[Tenders]T1[/Tenders]

[Customer]C1[/Customer]

[/Transaction]

[Transaction]

[Items]I2[/Items]

[Tenders]T2[/Tenders]

[Customer]C2[/Customer]

[/Transaction]

[IsPostVoid/]

[Transaction]

[Items][/Items]

[Tenders][/Tenders]

[Customer][/Customer]

[/Transaction]

[Transaction]

[Items]I4[/Items]

[Tenders]T4[/Tenders]

[Customer]C4[/Customer]

[/Transaction]

[/Transactions]

[/TLOG]

[/Contents]

[/PointOfSale]'

SELECT d.value('Items[1]','VARCHAR(10)') AS Item,

d.value('Tenders[1]','VARCHAR(10)') AS Tender,

d.value('Customer[1]','VARCHAR(10)') AS Customer,

d.value('for $a in . return local-name($a/../*[. << $a][last()])','VARCHAR(20)') AS PreviousElementName

FROM @xmlDoc.nodes('/PointOfSale/Contents/TLOG/Transactions/Transaction') AS x(d)

____________________________________________________

Deja View - The strange feeling that somewhere, sometime you've optimised this query before

How to get the best help on a forum

http://www.sqlservercentral.com/articles/Best+Practices/61537

MarksmanWaugh Old Hand Points: 300 More actions · Answer 2

Mark,

Cheers for the excellent response. Using my example that I provided I see how this caters to my needs. Unfortunately I dumbed down my example, here's a sample chunk of actual transaction code I am looking at:

[Transaction]

[Type]SREG[/Type]

[State]C[/State]

[Date]3/10/2008 2:13:00 PM[/Date]

[RegisterCode]9415[/RegisterCode]

[User]255[/User]

[UserTimeClockID]54595[/UserTimeClockID]

[UserLogin]cstine[/UserLogin]

[GUID]00415-9415-4584[/GUID]

[OpeningTender]0[/OpeningTender]

[BalanceFwd]0[/BalanceFwd]

[Charges]24.9900[/Charges]

[Taxes]1.62[/Taxes]

[Tenders]0[/Tenders]

[BalanceDue]26.6100[/BalanceDue]

[Voided /]

[PostVoid /]

[VoidDate]3/10/2008 4:45:45 PM[/VoidDate]

[VoidReasonCode /]

[VoidReasonOther /]

[VoidingTransactionGUID]00415-9415-4587[/VoidingTransactionGUID]

[NextItemNumber]6[/NextItemNumber]

[StoreUID]00415[/StoreUID]

[RegisterSequenceNumber]4584[/RegisterSequenceNumber]

[Sale]

[PaymentReqd]0[/PaymentReqd]

[MerchandiseIn]0[/MerchandiseIn]

[MerchandiseOut]1[/MerchandiseOut]

[/Sale]

[Items]

[Item]

[Type]MDSE[/Type]

[Charges]24.9900[/Charges]

[Taxes]0[/Taxes]

[Tenders]0[/Tenders]

[SequenceNo]1[/SequenceNo]

[Merchandise]

[Department]17[/Department]

[Class]17655[/Class]

[Style]276[/Style]

[Color]93[/Color]

[SKU]7629943[/SKU]

[Description]BASIC DENIM SHORTS[/Description]

[Quantity]1[/Quantity]

[Price]24.9900[/Price]

[QtyAtPrice]1[/QtyAtPrice]

[IsTaxable]true[/IsTaxable]

[MerchandiseAmount]24.9900[/MerchandiseAmount]

[Disposition]S[/Disposition]

[IsSpecialOrder]false[/IsSpecialOrder]

[/Merchandise]

[/Item]

[/Items]

[/Transaction]

I'd like to specifically look for the existence of the [PostVoid /] empty tag that may or may not appear in the highest level of the Transaction. It appears to always occur after the [BalanceDue][/BalanceDue] tags.

How can I go back further than the most recent element?

Thanks again!

Mark Cowne One Orange Chip Points: 26944 More actions · Answer 3

Maybe this?

declare @x xml

set @x='

... your xml

'

select

r.value('Type[1]','VARCHAR(6)') as Type,

r.value('GUID[1]','VARCHAR(25)') as GUID,

r.value('Date[1]','DATETIME') as Date,

r.value('RegisterCode[1]','VARCHAR(6)') as RegisterCode,

r.value('User[1]','BIGINT') as [User],

r.value('StoreUID[1]','VARCHAR(6)') as StoreUID,

r.value('Charges[1]','MONEY') as Charges,

r.value('Taxes[1]','MONEY') as Taxes,

r.value('Tenders[1]','MONEY') as Tenders,

case when r.value('PostVoid[1]','VARCHAR(20)') is not null then 'PostVoid found' else 'No PostVoid' end

from @x.nodes('/PointOfSale/Contents/TLOG/Transactions/Transaction') as x(r)

____________________________________________________

Deja View - The strange feeling that somewhere, sometime you've optimised this query before

How to get the best help on a forum

http://www.sqlservercentral.com/articles/Best+Practices/61537

MarksmanWaugh Old Hand Points: 300 More actions · Answer 4

Brilliant! I am off and running. For anyone in future that follows this thread this is what I ended up with:

DECLARE @iDoc INT

DECLARE @xmlDoc XML

SET @xmlDoc = (SELECT * FROM OPENROWSET ( BULK 'C:\tlog.xml', SINGLE_CLOB ) AS xmlData)

--Prepare the XML Document by executing a system stored procedure

EXEC SP_XML_PREPAREDOCUMENT @iDoc OUTPUT, @xmlDoc

-- INSERT statement for header table

INSERT INTO [Header_Table]

(

[Type],Mode,TrxID,OrigTrxID,Date,Register,[User],UserName,Store,

BalanceFwd,Charges,Taxes,Tenders,BalanceDue,CustomerID,LName,

FName,EmployeeID,EmpLName,EmpFName,ReasonCode

)

-- SELECT statement using XQUERY

SELECT

r.value('Type[1]','VARCHAR(6)') AS [Type],

CASE

WHEN r.value('PostVoid[1]','VARCHAR(20)') IS NOT NULL THEN 'Post Void'

WHEN r.value('Voided[1]','VARCHAR(20)') IS NOT NULL AND r.value('PostVoid[1]','VARCHAR(20)') IS NULL THEN 'Void'

WHEN r.value('(Sale/IsEmployeeTrans)[1]','VARCHAR(20)') IS NOT NULL THEN 'Emp Sale'

WHEN r.value('(TrainingMode)[1]','VARCHAR(20)') IS NOT NULL THEN 'Training Mode'

WHEN r.value('Type[1]','VARCHAR(20)') = 'NS' THEN 'No Sale'

WHEN r.value('Type[1]','VARCHAR(20)') = 'SLWAY' THEN 'Layaway'

WHEN r.value('Type[1]','VARCHAR(20)') = 'SREG' THEN 'Sales'

WHEN r.value('Type[1]','VARCHAR(20)') = 'Event' THEN 'Event'

ELSE 'Other' END AS Mode,

r.value('GUID[1]','VARCHAR(25)') AS [GUID],

r.value('OrigTransactionGUID[1]','VARCHAR(25)') AS OrigTransactionGUID,

r.value('Date[1]','DATETIME') AS Date,

r.value('RegisterCode[1]','VARCHAR(6)') AS RegisterCode,

r.value('User[1]','BIGINT') AS [User],

r.value('UserLogin[1]','VARCHAR(25)') AS UserLogin,

r.value('StoreUID[1]','VARCHAR(6)') AS StoreUID,

r.value('BalanceFwd[1]','MONEY') AS BalanceFwd,

r.value('Charges[1]','MONEY') AS Charges,

r.value('Taxes[1]','MONEY') AS Taxes,

r.value('Tenders[1]','MONEY') AS Tenders,

r.value('BalanceDue[1]','MONEY') AS BalanceDue,

r.value('(Customer/SyncID)[1]','VARCHAR(25)') AS SyncID,

r.value('(Customer/NameLast)[1]','VARCHAR(25)') AS NameLast,

r.value('(Customer/NameFirst)[1]','VARCHAR(25)') AS NameFirst,

r.value('(Sale/EmployeeID)[1]','VARCHAR(12)') AS EmployeeID,

r.value('(Sale/EmployeeNameFirst)[1]','VARCHAR(25)') AS EmpLName,

r.value('(Sale/EmployeeNameLast)[1]','VARCHAR(25)') AS EmpFName,

CASE

WHEN r.value('Type[1]','VARCHAR(20)') = 'NS' THEN r.value('(NoSale/ReasonCode)[1]','VARCHAR(25)')

ELSE '' END AS ReasonCode

FROM @xmlDoc.nodes('/PointOfSale/Contents/TLOG/Transactions/Transaction') AS x(r)

WHERE NOT EXISTS (SELECT * FROM [Header_Table] WHERE TrxID = r.value('GUID[1]','VARCHAR(25)'))

An observation though. While the query (without insert) was running a couple seconds on a 30,000 line XML file; it's taking a few minutes to write to a new empty table. And I expect it to get worse as the table grows (obviously) and as I tweak the indexing I choose to use.

I suppose the extra leg-work to read through the file to honour my CASE statement is the main culprit. I can handle a few minutes no problem, it will be interesting to monitor as I go down the road.

Thanks Mark!