Question:
How do I get a dynamic
format output from Oracle? I want to write an Oracle PL/SQL that provides
XML and/or HTML formatted data dynamically. The original of this was a
"generic" way of reading the output of a stored procedure for
development like the SQL Server TSQL, which formats output automatically.
Oracle SQL can be
embedded in almost any popular procedural language, and Oracle PL/SQL is quite
robust, allowing embedded Java.
Oracle’s XML Publisher
product has callable procedures that can retrieve Oracle data and create
reports with graphs and images, and then format, mail, fax, print, or FTP them
to a remote device.
For formatting Oracle
output, Oracle has the dbms_xmlgen
PL/SQL package. This package generates XML "on the fly" using any
Oracle SQL query you want. The dbms_xmlgen
package is extremely easy to use from either the SQL prompt or in code, as it’s
just a simple query.
Generating formatted XML From Oracle
Take this standard
query as a semple:
SQL> select
employee_id, first_name, last_name, phone_number
2 from
employees where rownum < 6
EMPLOYEE_ID
FIRST_NAME LAST_NAME PHONE_NUMBER
-----------
-------------------- ------------------
------------
100 Steven King 515.123.4567
101 Neena Kochhar 515.123.4568
102 Lex De Haan 515.123.4569
103 Alexander Hunold 590.423.4567
104 Bruce Ernst 590.423.4568
We get our standard
output, but with no formatting. It's easy to transform this Oracle output into
properly formatted XML. All we do is change the SQL to embed the
requested columns into a call to the dbms_xmlgen.getxml
procedure:
set pages 0set linesize 150set long 9999999set head off SQL> select dbms_xmlgen.getxml('select employee_id, first_name, 2 last_name, phone_number from employees where rownum < 6') xml 3 from dualOUTPUT <?xml version="1.0"?><ROWSET> <ROW> <EMPLOYEE_ID>100</EMPLOYEE_ID> <FIRST_NAME>Steven</FIRST_NAME> <LAST_NAME>King</LAST_NAME> <PHONE_NUMBER>515.123.4567</PHONE_NUMBER> </ROW> <ROW> <EMPLOYEE_ID>101</EMPLOYEE_ID> <FIRST_NAME>Neena</FIRST_NAME> <LAST_NAME>Kochhar</LAST_NAME> <PHONE_NUMBER>515.123.4568</PHONE_NUMBER> </ROW> <ROW> <EMPLOYEE_ID>102</EMPLOYEE_ID> <FIRST_NAME>Lex</FIRST_NAME> <LAST_NAME>De Haan</LAST_NAME> <PHONE_NUMBER>515.123.4569</PHONE_NUMBER> </ROW> <ROW> <EMPLOYEE_ID>103</EMPLOYEE_ID> <FIRST_NAME>Alexander</FIRST_NAME> <LAST_NAME>Hunold</LAST_NAME> <PHONE_NUMBER>590.423.4567</PHONE_NUMBER> </ROW> <ROW> <EMPLOYEE_ID>104</EMPLOYEE_ID> <FIRST_NAME>Bruce</FIRST_NAME> <LAST_NAME>Ernst</LAST_NAME> <PHONE_NUMBER>590.423.4568</PHONE_NUMBER> </ROW></ROWSET>
Fully compliant XML
that can be easily integrated into any application, with ROWSET and ROW tags in
place to identify nodes, and tags for each column you pulled out of the
database.
All we had to do was
wrap the query in the DBMS_XMLGEN.GETXML
function call, selected from DUAL. The query remained exactly the same.
Advanced formatting of Oracle data
Let’s take this easy
formatting one step further and show how Oracle automatically formats
hierarchical reports. Most XML has subnodes for each main node, allowing a
formatted hierarchy. For example, assume we wanted to pull XML for every
department, and a subnode for every employee under it? For this formatting, we
use the CURSOR function!
SQL> select department_id, department_name, 2 cursor(select first_name, last_name 3 from employees e 4 where e.department_id = d.department_id) emp_row 5 from departments d 6* where rownum < 4 DEPARTMENT_ID DEPARTMENT_NAME EMP_ROW------------- ------------------------------ -------------------- 10 Administration CURSOR STATEMENT : 3 CURSOR STATEMENT : 3 FIRST_NAME LAST_NAME-------------------- -------------------------Jennifer Whalen 20 Marketing CURSOR STATEMENT : 3 CURSOR STATEMENT : 3 FIRST_NAME LAST_NAME-------------------- -------------------------Michael HartsteinPat Fay 30 Purchasing CURSOR STATEMENT : 3 CURSOR STATEMENT : 3 FIRST_NAME LAST_NAME-------------------- -------------------------Den RaphaelyAlexander KhooShelli BaidaSigal TobiasGuy HimuroKaren Colmenares 6 rows selected. SQL> select dbms_xmlgen.getxml(' 2 select department_id, department_name, 3 cursor(select first_name, last_name 4 from employees e 5 where e.department_id = d.department_id) emp_row 6 from departments d 7 where rownum < 4 8* ') from dual <?xml version="1.0"?><ROWSET> <ROW> <DEPARTMENT_ID>10</DEPARTMENT_ID> <DEPARTMENT_NAME>Administration</DEPARTMENT_NAME> <EMP_ROW> <EMP_ROW_ROW> <FIRST_NAME>Jennifer</FIRST_NAME> <LAST_NAME>Whalen</LAST_NAME> </EMP_ROW_ROW> </EMP_ROW> </ROW> <ROW> <DEPARTMENT_ID>20</DEPARTMENT_ID> <DEPARTMENT_NAME>Marketing</DEPARTMENT_NAME> <EMP_ROW> <EMP_ROW_ROW> <FIRST_NAME>Michael</FIRST_NAME> <LAST_NAME>Hartstein</LAST_NAME> </EMP_ROW_ROW> <EMP_ROW_ROW> <FIRST_NAME>Pat</FIRST_NAME> <LAST_NAME>Fay</LAST_NAME> </EMP_ROW_ROW> </EMP_ROW> </ROW> <ROW> <DEPARTMENT_ID>30</DEPARTMENT_ID> <DEPARTMENT_NAME>Purchasing</DEPARTMENT_NAME> <EMP_ROW> <EMP_ROW_ROW> <FIRST_NAME>Den</FIRST_NAME> <LAST_NAME>Raphaely</LAST_NAME> </EMP_ROW_ROW> <EMP_ROW_ROW> <FIRST_NAME>Alexander</FIRST_NAME> <LAST_NAME>Khoo</LAST_NAME> </EMP_ROW_ROW> <EMP_ROW_ROW> <FIRST_NAME>Shelli</FIRST_NAME> <LAST_NAME>Baida</LAST_NAME> </EMP_ROW_ROW> <EMP_ROW_ROW> <FIRST_NAME>Sigal</FIRST_NAME> <LAST_NAME>Tobias</LAST_NAME> </EMP_ROW_ROW> <EMP_ROW_ROW> <FIRST_NAME>Guy</FIRST_NAME> <LAST_NAME>Himuro</LAST_NAME> </EMP_ROW_ROW> <EMP_ROW_ROW> <FIRST_NAME>Karen</FIRST_NAME> <LAST_NAME>Colmenares</LAST_NAME> </EMP_ROW_ROW> </EMP_ROW> </ROW></ROWSET>Note that the query only added dbms_xmlgen.getxml('
We have each DEPARTMENT as a ROW tag, and the
cursor we created gives us an EMP_ROW node containing recurring EMP_ROW_ROW
nodes.Conclusions on dbms_xmlgen
The dbms_xmlgen procedure can be extremely useful for quick retrieval of Oracle records, formatted for web browser display. With these formatting procedures you can display the output of any query directly to the screen, and you have an easy XML display program. The best part comes with easily formatting Oracle reports. XML Publisher is made to accept XML that looks just like this and form extremely detailed reports using templates made in Microsoft Word.
With queries such as these and XML Publisher you can have a full reporting suite that easily pulls data, forms it into a PDF, DOC, XLS, or HTML report, and distributes it anywhere you would like it to go.
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