Using COBOL with pureXML on DB2 for z/OS...– DB2 10 for z/OS • New features (Sub-document...

1

© 2012 IBM Corporation

Information Management

Using COBOL with pureXML on DB2 for z/OS

2 © 2012 IBM Corporation


Agenda

■ Introduction■ XML Host Variables in COBOL■ SQL/XML Functions■ Insert and Retrieval XML Data■ Update and Delete XML Data■ Trigger to Extract Relational Data from XML Data■ Analyzing Access Plan with or without XML Indexes■ DESCRIBE Statement Referring to an XML Column■ FETCH WITH CONTINUE and FETCH CURRENT

CONTINUE on XML Data■ XML Sub-document Update



Introduction

Minimum Requirement:– DB2 9 for z/OS– Enterprise COBOL for z/OS V3R4

Recommend Requirement:– DB2 10 for z/OS

• New features (Sub-document update, XQuery, Binary XML, XML support in SQL PL and UDF, etc)

• Enhancement on performance and storage– Enterprise COBOL for z/OS V4R1

DB2 Precompiler or DB2 Coprocessor Purpose of COBOL samples:

– Problems from users– Illustrate DB2 for z/OS pureXML features in COBOL

Where are the COBOL Samples?http://www.ibm.com/developerworks/wikis/display/db2xml/DB2+for+zOS+pureXML



DDL for COBOL Samples

CREATE TABLE PURCHASE_ORDER ( PODOCID INTEGER, PODOC XML );

CREATE INDEX POINDEX1 ON PURCHASE_ORDER (PODOC) GENERATE KEY USING XMLPATTERN '/purchaseOrder/items/item/productName' AS SQL VARCHAR(30)



XML Storage

PURCHASE_ORDER

B+tree

DocID index

XML Table

B+tree

NodeID index

B+tree

XML index (POINDEX1)

DOCID MIN_NODEID XMLDATA

PODOCID PODOCDocID



An Example of PURCHASE ORDER DOCUMENT<purchaseOrder orderDate="2010-08-18"> <shipTo country="US"> <name>Alice Smith</name> <street>123 Maple Street</street> <city>San Jose</city><state>California</state><zip>95123</zip> </shipTo> <billTo country="US"> <name>Robert Smith</name> <street>8 Oak Avenue</street> <city>San Jose</city><state>California</state><zip>95123</zip> </billTo> <comment>Hurry, my lawn is going wild!</comment> <items> <item partNum="872-AA"> <productName>Lawnmower</productName> <quantity>1</quantity><USPrice>149.99</USPrice> <comment>Confirm this is gas powered</comment> <shipDate>2010-08-20</shipDate> </item> </items> </purchaseOrder>



XML Host Variables01 XMLCLOB USAGE IS SQL TYPE IS XML AS CLOB(10K).01 XMLBLOB USAGE IS SQL TYPE IS XML AS BLOB(10K).01 XMLDBCLOB USAGE IS SQL TYPE IS XML AS DBCLOB(10K).

Modified Source by DB2 Precompiler:

01 XMLCLOB. 02 XMLCLOB-LENGTH PIC 9(9) COMP-5. 02 XMLCLOB-DATA. 49 FILLER PIC X(10240).

01 XMLBLOB. 02 XMLBLOB-LENGTH PIC 9(9) COMP-5. 02 XMLBLOB-DATA. 49 FILLER PIC X(10240).

01 XMLDBCLOB. 02 XMLDBCLOB-LENGTH PIC 9(9) COMP-5. 02 XMLDBCLOB-DATA. 49 FILLER PIC G(10240) USAGE DISPLAY-1.



Avoiding Data Conversion



More XML Host Variables01 BLOB-XML-FILE USAGE IS SQL TYPE IS XML AS BLOB-FILE.01 CLOB-XML-FILE USAGE IS SQL TYPE IS XML AS CLOB-FILE.01 DBCLOB-XML-FILE USAGE IS SQL TYPE IS XML AS DBCLOB-FILE.

01 BLOB-XML-FILE. 49 BLOB-XML-FILE-NAME-LENGTH PIC S9(9) COMP-5 SYNC. 49 BLOB-XML-FILE-DATA-LENGTH PIC S9(9) COMP-5. 49 BLOB-XML-FILE-FILE-OPTION PIC S9(9) COMP-5. 49 BLOB-XML-FILE-NAME PIC X(255).

01 CLOB-XML-FILE. 49 CLOB-XML-FILE-NAME-LENGTH PIC S9(9) COMP-5 SYNC. 49 CLOB-XML-FILE-DATA-LENGTH PIC S9(9) COMP-5. 49 CLOB-XML-FILE-FILE-OPTION PIC S9(9) COMP-5. 49 CLOB-XML-FILE-NAME PIC X(255).

01 DBCLOB-XML-FILE. 49 DBCLOB-XML-FILE-NAME-LENGTH PIC S9(9) COMP-5 SYNC. 49 DBCLOB-XML-FILE-DATA-LENGTH PIC S9(9) COMP-5. 49 DBCLOB-XML-FILE-FILE-OPTION PIC S9(9) COMP-5. 49 DBCLOB-XML-FILE-NAME PIC X(255).



SQL/XML Functions XMLEXISTS

SELECT COUNT(DISTINCT PODOCID) INTO :HV-COUNT FROM PURCHASE_ORDER WHERE XMLEXISTS ('//item[@partNum = "872-AA"]' PASSING PODOC)

XMLQUERYSELECT XMLQUERY( '//item[@partNum = "872-AA"]' PASSING PODOC)INTO :HV-XML-CLOB FROM PURCHASE_ORDER WHERE PODOCID = 1

XMLTABLESELECT X.ORDERDATE, X.SHIPDATE INTO :HV-DATE1, :HV-DATE2FROM PURCHASE_ORDER,

XMLTABLE('/purchaseOrder[.//item/@partNum="872-AA"]' PASSING PODOC COLUMNS ORDERDATE DATE PATH '@orderDate' , SHIPDATE DATE PATH 'items/item[@partNum = "872-AA"]/shipDate' ) AS X WHERE PODOCID = 1

XMLCASTSELECT XMLCAST(XMLQUERY( '/purchaseOrder/@orderDate' PASSING PODOC)

AS DATE) INTO :HV-DATE FROM PURCHASE_ORDER WHERE PODOCID = 1



Insert XML Data

•Insert from literalINSERT INTO PURCHASE_ORDER (PODOCID, PODOC) VALUES (1, '<purchaseOrder orderDate="2010-08-18">…</purchaseOrder>')INSERT INTO PURCHASE_ORDER (PODOCID, PODOC) VALUES (2, XMLPARSE(DOCUMENT '......' PRESERVE WHITESPACE))•Insert from Host Variable01 HV-CLOB1 SQL TYPE IS XML AS CLOB(3K).01 HV-CLOB-LOCATOR01 SQL TYPE IS CLOB-LOCATOR.INSERT INTO PURCHASE_ORDER (PODOCID, PODOC) VALUES(3, :HV-CLOB1) INSERT INTO PURCHASE_ORDER (PODOCID, PODOC) VALUES(4, :HV-CLOB-LOCATOR01)



Insert XML Data (Cont.)•Insert from File Reference Host Variable01 HV-XML-CLOB-FILE SQL TYPE IS XML AS CLOB-FILE.MOVE 23 TO HV-XML-CLOB-FILE-NAME-LENGTH. MOVE "SYSADM.XMLSAMP.CLOBFILE" TO HV-XML-CLOB-FILE-NAME.MOVE SQL-FILE-READ TO HV-XML-CLOB-FILE-FILE-OPTION. EXEC SQL INSERT INTO PURCHASE_ORDER (PODOCID, PODOC) VALUES(5, :HV-XML-CLOB-FILE) END-EXEC. •FILE OPTIONS

•SQL-FILE-READ : 2 •SQL-FILE-CREATE : 8 •SQL-FILE-OVERWRITE : 16 •SQL-FILE-APPEND : 32



• Simple select:SELECT PODOCFROM PURCHASE_ORDERWHERE PODOCID = 1

• Select with condition:SELECT PODOCFROM PURCHASE_ORDERWHERE XMLEXISTS('//item[@partNum = "872-AA"]' PASSING PODOC)

• Extract from a document:SELECT XMLQUERY(‘/purchaseOrder/@orderDate’ PASSING PODOC)FROM PURCHASE_ORDER WHERE XMLEXISTS('//item[@partNum = "872-AA"]' PASSING PODOC)

Retrieving XML Data



Retrieving XML Data to File Reference Host Variable

01 HV-XML-CLOB-FILE SQL TYPE IS XML AS CLOB-FILE.

MOVE 17 TO HV-XML-CLOB-FILE-NAME-LENGTH. MOVE "/tmp/xmldoc01.txt" TO HV-XML-CLOB-FILE-NAME.MOVE SQL-FILE-OVERWRITE TO HV-XML-CLOB-FILE-FILE-OPTION.

EXEC SQL SELECT PODOC INTO :HV-XML-CLOB-FILE FROM PURCHASE_ORDER WHERE PODOCID = 1 END-EXEC.



•Updating an XML Column

01 HV-CLOB1 SQL TYPE IS XML AS CLOB(2048).EXEC SQL UPDATE PURCHASE_ORDER SET PODOC = :HV-CLOB1 WHERE PODOCID = 1 END-EXEC.

•Delete Rows Based on XML Data

EXEC SQL DELETE FROM PURCHASE_ORDER WHERE XMLEXISTS ('//item[@partNum = "872-AA"]' PASSING PODOC) END-EXEC.

Update and Delete on XML Data



CREATE TRIGGER INS_CUST AFTER INSERT ON CUSTOMER_INFO REFERENCING NEW AS NEWROW FOR EACH ROW MODE DB2SQL BEGIN ATOMIC UPDATE CUSTOMER_INFO SET (CUST_NAME, CUST_ADDR, CUST_CITY, CUST_ZIP) = (SELECT X.NAME, X.ADDR, X.CITY, X.ZIP FROM CUSTOMER_INFO AS C , XMLTABLE('customer' PASSING C.CUST_INFO COLUMNS NAME VARCHAR(30) PATH 'name', CITY VARCHAR(30) PATH 'city', ZIP VARCHAR(12) PATH 'zip' , ADDR VARCHAR(100) PATH 'street' ) AS X WHERE C.CUST_ID = NEWROW.CUST_ID ) WHERE CUST_ID = NEWROW.CUST_ID ; END

Trigger to Extract Relational Data from XML Data



CREATE TABLE CUSTOMER_INFO ( CUST_ID INTEGER, CUST_NAME VARCHAR(30), CUST_ADDR VARCHAR(100), CUST_CITY VARCHAR(30), CUST_ZIP VARCHAR(12), CUST_INFO XML )

INSERT INTO CUSTOMER_INFO (CUST_ID, CUST_INFO) VALUES (1, '<customer country="US"><name>Alice Smith</name>...</customer>') SELECT CUST_NAME FROM CUSTOMER_INFO WHERE CUST_ID = 1

+--------------------------------+ | CUST_NAME | +--------------------------------+ 1_| Alice Smith | +--------------------------------+

Trigger to Extract Relational Data from XML Data (Cont.)



Create XML Indexes

CREATE INDEX POINDEX1 ON PURCHASE_ORDER (PODOC) GENERATE KEY USING XMLPATTERN '/purchaseOrder/items/item/productName' AS SQL VARCHAR(30)

CREATE INDEX POINDEX2 ON PURCHASE_ORDER (PODOC) GENERATE KEY USING XMLPATTERN '/purchaseOrder/items/item/USPrice' AS SQL DECFLOAT



Explain Queries with XML IndexesEXPLAIN ALL SET QUERYNO = 1 FOR SELECT PODOCID FROM PURCHASE_ORDER WHERE XMLEXISTS('/purchaseOrder/items/item[productName ="Lawnmower"]' PASSING PODOC)

EXPLAIN ALL SET QUERYNO = 2 FOR SELECT PODOCID FROM PURCHASE_ORDER WHERE XMLEXISTS('/purchaseOrder/items/item[USPrice > 100]' PASSING PODOC)

EXPLAIN ALL SET QUERYNO = 3 FOR SELECT PODOCID FROM PURCHASE_ORDER WHERE XMLEXISTS('/purchaseOrder/items/item[productName ="Lawnmower" and 'USPrice >100]' PASSING PODOC)

EXPLAIN ALL SET QUERYNO = 4 FOR SELECT PODOCID FROM PURCHASE_ORDER WHERE XMLEXISTS('/purchaseOrder/items/item[productName ="Lawnmower" or 'USPrice >100]' PASSING PODOC)



Explain Results with XML Indexes+-----------------------------------------+| QUERYNO | ACCESSTYPE | ACCESSNAME |+-----------------------------------------+| 0001 | DX | POINDEX1 || 0002 | DX | POINDEX2 || 0003 | M | || 0003 | DX | POINDEX1 || 0003 | DX | POINDEX2 || 0003 | DI | || 0004 | M | || 0004 | DX | POINDEX1 || 0004 | DX | POINDEX2 || 0004 | DU | |+-----------------------------------------+



Explain Results without XML Indexes

DROP INDEX POINDEX1DROP INDEX POINDEX2

+-----------------------------------------+| QUERYNO | ACCESSTYPE | ACCESSNAME |+-----------------------------------------+| 0001 | R | || 0002 | R | || 0003 | R | || 0004 | R | |+-----------------------------------------+



DESCRIBE Statement Referring to an XML Column 01 HV-STMT. 49 HV-STMT-LEN PIC S9(4) COMP. 49 HV-STMT-DATA PIC X(240). MOVE 75 TO HV-STMT-LEN.MOVE 'SELECT PODOC, XML2CLOB(PODOC) FROM ADMF001.PURCHASE_ORDER WHERE PODOCID = 1' TO HV-STMT-DATA. PREPARE STMT1 FROM :HV-STMT DESCRIBE STMT1 INTO :SQLDA

After the Execution of DESCRIBE statement:SQLTYPE(1) = 0989 (XML data type in DB2)SQLTYPE(2) = 0409 (CLOB data type in DB2)



FETCH XML Data Based on the DESCRIBE SQLDA SET SQLDATA(1) TO ADDRESS OF HV-XML-CLOB. SET SQLIND(1) TO ADDRESS OF HV-XML-CLOB-IND. SET SQLDATA(2) TO ADDRESS OF HV-CLOB. SET SQLIND(2) TO ADDRESS OF HV-CLOB-IND. FETCH C1 USING DESCRIPTOR :SQLDA -804 AN ERROR WAS FOUND IN THE APPLICATION PROGRAM INPUT PARAMETERS FOR THE SQL STATEMENT, REASON 16RC16 : Unrecognized output data type. MOVE 409 TO SQLTYPE(1). MOVE 0 TO SQLLEN(1) . MOVE 1048576 TO SQLLONGLEN(3). FETCH C1 USING DESCRIPTOR :SQLDA



FETCH WITH/CURRENT CONTINUE on XML Data

01 HV-INTEGER PIC S9(4) COMP.01 HV-XML-CLOB SQL TYPE IS XML AS CLOB(100).DECLARE C1 CURSOR FOR SELECT PODOCID, PODOC FROM PURCHASE_ORDER WHERE PODOCID = 1 FETCH C1 INTO :HV-INTEGER, :HV-XML-CLOB==> SQLCODE = -433, ERROR: VALUE <XML-Value> IS TOO LONG

FETCH WITH CONTINUE C1 INTO :HV-INTEGER, :HV-XML-CLOB==> HV-XML-CLOB-LENGTH = 641

FETCH CURRENT CONTINUE C1 INTO :HV-INTEGER, :HV-XML-CLOB ==> HV-XML-CLOB-LENGTH = 541 HV-XML-CLOB-LENGTH = 441 HV-XML-CLOB-LENGTH = 341 ......



XML Sub-document Update (DB2 10) EXEC SQL UPDATE PURCHASE_ORDER SET PODOC = XMLMODIFY( 'insert nodes $item as last into /purchaseOrder/items', XMLPARSE(DOCUMENT '<item partNum="747-BB">- ' <productName>Ruby Ring</productName>- ' <quantity>1</quantity><USPrice>75.50</USPrice>- ' <shipDate>2012-08-21</shipDate> - '</item>') as "item") WHERE PODOCID = 1001 END-EXEC



XML Sub-document Update (Cont.) No easy way to update parts of a document in DB2 9Only simple update: insert, replace, delete from XQuery

update facilityXMLMODIFY can only be used in RHS of UPDATE SET.Only changed rows in XML table are updated



Conclusion

■ Introduction■ XML Host Variables and SQL/XML Functions■ Insert, Retrieval, Update and Delete XML Data■ Trigger to Extract Relational Data from XML Data■ Analyzing Access Plan with or without XML Indexes■ DESCRIBE Statement Referring to an XML Column■ FETCH WITH CONTINUE and FETCH CURRENT

CONTINUE on XML Data■ XML Sub-document Update

Using COBOL with pureXML on DB2 for z/OS...– DB2 10 for z/OS • New features (Sub-document...

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