Oracle Apps XML Interface: Design

Oracle Apps
XSD Registration Process:

XSD is schema definition file and its needs to be registered in Oracle database. This is one time process and will be required to be re-executed only if the XSD is modified. Following are the steps for XSD Registration

1.    XSD file is available in the UNIX directory. This file is read using UTL_FILE and inserted into the table as LOB object using DBMS_LOB package.

  ---Insert a Empty CLOB record with XSD details

  INSERT INTO testxml_sources

      (  source_id

        ,source_name

        ,xml_schema_name

        ,xml_schema

        ,start_date

        ,end_date

      )

    VALUES (l_source_id

         ,p_source_name

         ,p_schema_url

         ,EMPTY_CLOB()

         ,SYSDATE

         ,NULL

         )

         RETURNING

          --Return the LOB locator

          xml_schema INTO l_xml_schema_definition;

   

    ---Create a BFILE Pointer for the XSD file residing in <UNIX DIR>

    l_src_file := BFILENAME(<UNIX DIR>, <XSD_FILE_NAME>);

    --Open the file

    DBMS_LOB.FILEOPEN(l_src_file, DBMS_LOB.FILE_READONLY);

   

     -- Read the file into the l_xml_schema_definition from l_src_file

    DBMS_LOB.LOADFROMFILE (  dest_lob => l_xml_schema_definition

                                               , src_lob  => l_src_file

                                                , amount   => DBMS_LOB.LOBMAXSIZE

                                             );

    DBMS_LOB.CLOSE (l_src_file );

  

2.    If a new XSD File comes in because of any changes in XSD definition, the record for the old XSD in the table is end dated and a new record is inserted into the table with Latest XSD file. This makes sure that Old XSD records retrieval is possible from database for any purpose.

      UPDATE testxml_sources

      SET    end_date        = TRUNC(SYSDATE)

      WHERE  source_name     = p_source_name

      AND    xml_schema_name = p_schema_url

      AND    end_date        IS NULL

      AND    SYSDATE         BETWEEN start_date

       AND     NVL(end_date,SYSDATE+1);

3.    Now the XSD in database is registered. Incase any Old XSD schema definition is present its deleted and new XSD is registered. DBMS_XMLSCHEMA function used for registration creates a XSD record in standard table

    --Get the XSD from Database

    SELECT xml_schema

               ,xml_schema_name

    INTO    l_schema

               ,l_schema_name

    FROM   testxml_sources

    WHERE source_name = p_source_name

    AND  SYSDATE      BETWEEN start_date AND NVL(end_date,SYSDATE+1);

    --Delete Old definition

    DBMS_XMLSCHEMA.DELETESCHEMA(l_schema_name,

                                                      DBMS_XMLSCHEMA.DELETE_CASCADE);

    --Register New Definition

    DBMS_XMLSCHEMA.REGISTERSCHEMA(schemaURL =>l_schema_name 

                                                        ,schemaDoc  => l_schema);

XML Data file Processing:

XML file holds the data that is to be loaded and validated. XML file contains the name of XSD that will be by default used for validation of the XML file. However in the current process explained here we have forced the XSD to be used for XSD validation. This process is three stages

1. Importing the File in Database:

    XML Data file resides in the UNIX BOX in predefined path. This file is first imported  

    as CLOB object into the XML Data file storage table.

---Insert a Empty CLOB record with XML File details

INSERT INTO testxml_data_files

       (source_id

       ,file_id

       ,xml_file

       ,load_date

       ,file_name

       )

       VALUES

       (l_source_id

       ,l_file_id

       ,EMPTY_CLOB()

       ,p_xml_file_name

       );         

    RETURNING

          --Return the LOB locator

          xml_file INTO l_xml_file;

   

    ---Create a BFILE Pointer for the XML file residing in <UNIX DIR>

     l_src_file := BFILENAME(<UNIX DIR>,<XML FILE>);

    --Open the file

    DBMS_LOB.FILEOPEN(l_src_file, DBMS_LOB.FILE_READONLY);

   

    -- Read the file into the l_xml_file from l_src_file

    DBMS_LOB.LOADFROMFILE (  dest_lob => l_xml_file

                                               , src_lob  => l_src_file

                                                , amount   => DBMS_LOB.LOBMAXSIZE

                                             );

    DBMS_LOB.CLOSE (l_src_file );

2. Validate the XML Data file:

    The XML Data file is validated against the XSD file using xmltype.schemavalidate

    function. This function by default will use the XSD specified inside the XML for

    validation, but here we have forced it to use the XSD passed. Incase of any

    validation failure of XML against the XSD, it will throw an Exception.

        --Declare following variables

        l_xml_data                  testxml_data_files.xml_file%TYPE;

        l_xml_schema_name   testxml_sources.xml_schema_name%TYPE;

        l_xml_type_0              XMLTYPE;

        l_xml_type                  XMLTYPE;

        --Fetch the Xml file details from the table

        SELECT sdf.xml_file

                   ,sxs.xml_schema_name

        INTO     l_xml_data

                   ,l_xml_schema_name

        FROM   testxml_data_files sdf

                  ,testxml_sources    sxs

        where sxs.source_id       = sdf.source_id

        AND   sxs.xsd_version     = sdf.xsd_version

        and    sxs.source_name     = p_source_name

        and    sdf.file_id         = p_file_id

        AND   SYSDATE             BETWEEN sxs.start_date

                                  AND NVL(sxs.end_date,SYSDATE+1);

   

    --Cast the CLOB into XML Type data type

    l_xml_type_0  := XMLTYPE.createxml(l_xml_data);

   

    --Specify the Name of XSD to be used for validation

    l_xml_type    := l_xml_type_0.createschemabasedxml(l_xml_schema_name);

    l_xml_type.setschemavalidated(1);  

     --Validate the XML Data file

    xmltype.schemavalidate(l_xml_type);

3. Load the XML Data into the staging Table.

    The data contained in the XML File once validated is loaded into the Staging table

    using standard XML Functions. The PLSQL code used here is specific to the

    structure of XML file.

--Declare variables

l_xml_data                     testxml_data_files.xml_file%TYPE;

l_xml_schema_name       testxml_sources.xml_schema_name%TYPE;

l_xml_type                     XMLTYPE;

--Fetch the Data file record in CLOB object

SELECT sdf.xml_file

           ,sxs.xml_schema_name

           ,sxs.source_id

INTO    l_xml_data

          ,l_xml_schema_name

          ,l_source_id

FROM   testxml_data_files sdf

          ,testxml_sources    sxs

WHERE sxs.source_id   = sdf.source_id

AND   sxs.source_name = p_source_name

AND   sdf.file_id     = p_file_id

AND   SYSDATE         BETWEEN sxs.start_date

                       AND     NVL(sxs.end_date,SYSDATE+1);

--Cast CLOB data into an XML type

l_xml_type :=XMLTYPE.CREATEXML(l_xml_data);

    First FOR Loop is opened for the Parameters which are attributes of the File and

    not the actual data of the file. These attributes of the XML File can be used to take

    decisions related to processing of the file.

    E.g. the attribute xsdversion defines the version of XSD to be used for validating

    the XML File

FOR l_invoice_rec IN

( SELECT   EXTRACTVALUE(VALUE(XMLD), '/Invoice /@title')             title

, EXTRACTVALUE(VALUE(XMLD), '/Invoice/@xsdversion')        xsdversion

, EXTRACTVALUE(VALUE(XMLD), '/Invoice/@purpose')           purpose                           , EXTRACTVALUE(VALUE(XMLD), '/Invoice/@create_date')       create_date

, EXTRACTVALUE(VALUE(XMLD), '/Invoice/@create_time')       create_time

, EXTRACTVALUE(VALUE(XMLD), '/Invoice/@receiver_name')   receiver_name

, ROWNUM                                                  rn

 FROM

TABLE(XMLSEQUENCE(l_xml_type.EXTRACT(‘Invoice '))) XMLD)

LOOP       

--Open loop of processing data for Invoice Header

FOR l_header_rec IN

(SELECT

EXTRACTVALUE(VALUE(XMLD), '/header/transaction_date') transaction_date

, EXTRACTVALUE(VALUE(XMLD), '/header/Invoicenum’)    Invoicenum

, EXTRACTVALUE(VALUE(XMLD), '/header/Customer ')      Customer,

, EXTRACTVALUE(VALUE(XMLD), '/header/Shipto ')          Shipto,

, EXTRACTVALUE(VALUE(XMLD), '/header/TotAmount ')    TotAmount,

, ROWNUM                                                     rn

FROM

TABLE(XMLSEQUENCE(l_xml_type.EXTRACT('Invoice/header'))) XMLD)

LOOP

    --Open the Loop for Invoice Line data

    FOR l_line_rec IN

    ( SELECT 

    EXTRACTVALUE(VALUE(XMLD), '/line /item')        item,

    ,EXTRACTVALUE(VALUE(XMLD), '/line/price')        price,

    ,EXTRACT(VALUE(XMLD),'/transaction/amount')   amount

    ,ROWNUM                                                     rn

    FROM

    TABLE(XMLSEQUENCE(l_xml_type.EXTRACT(‘Invoice/Header/line’))) XMLD)

    LOOP       

        INSERT INTO  INOVICE_LINE_STG

          (line_id

          ,transaction_date

          ,invoicenum

          ,customer

          ,shipto

          ,item

          ,price

          ,amount)

        VALUES

          (line_id.nextval

          , l_header_rec.transaction_date

          , l_header_rec.Invoicenum

          ,l_header_rec.Customer

          ,l_header_rec.Shipto

          ,l_line_rec.item

          ,l_line_rec.price

          ,l_line_rec.amount);

    END LOOP;

END LOOP;

END LOOP;

Though in above step the Invoice Header and Line data is loaded into the same table, with use of some PLSQL Code this data can be loaded into two different tables based on Business requirement.