Did You Know? -- January 2001

By Hervé Deschamps, Oracle Corporation.



Portal 3.0.: Direct Access URLs

This is very useful when you want to construct a navigation bar. You can access Oracle Portal objects by entering the appropriate path.
Object URL
Page http://<hostname:port>/<DAD>/url/page/<pagename>
Folder http://<hostname:port>/<DAD>/url/folder/<foldername>
Category http://<hostname:port>/<DAD>/url/category/<categoryname>
Perspective http://<hostname:port>/<DAD>/url/perspective/<perspectivename>
Document http://<hostname:port>/<DAD>/docs/<docname>


Third-generation mobile devices capable of wireless video

Third-generation mobile devices capable of wireless video and enhanced audio streaming could be on sale before Christmas 2001, according to Intel Wednesday.

The chip giant teamed up with its latest business partner Analog Devices to announce they had successfully developed a new digital signal processor (DSP), called Micro Signal Architecture, designed for third-generation (3G) mobile computing devices.

The duo claim the DSP boasts a six to tenfold increase in performance and improved power management features for 3G.

The chip maker plans to bundle the technology along with its existing XScale processor and flash memory in its Personal Internet Client Architecture (PCA) -- a package designed for next generation mobile devices which will combine the functionality of both a mobile phone and a handheld PC.

Null trap in SQL and PL/SQL

Little puzzle: what do you think that will be displayed if you run this in SQL*Plus:

  s varchar2(1000) := '123<body>This is t-10.</body>123';
  b varchar2(1000) := null;
  r varchar2(1000);
  r := substr(s,1+length(b), 23);

Answer: 123<body>This is t-10.

Well, not exactly. You will get 'null'. Just as if you run this:

select 1+length(null) from dual;

You get a null. Watch those null values! length(null) is null and 1+null=null.

Portal 3.0. Custom attributes

Bad news about custom attributes in Portal30. When the attribute is a text one, its length is limited to 2000 characters. This is because the attribute values are stored
in table wwv_thingatttributes and if you look at the definition of the column 'value' you will see varchar2(2000). If you like to learn about internal Portal tables, here
is another one that contains the definition of you attributes: wwsbr_attribute$ together with internal attributes.

To add to the 2000 character limitation for custom text attributes, it seems that the UI of Portal does not even allow 2000 characters anyway. I get the error below when I enter 1500 characters or more. 1000 works.

ORA-06550: line 3, column 14:
PLS-00201: identifier 'PORTAL30.WWSBR_TYPE' must be declared
ORA-06550: line 3, column 14:
PL/SQL: Item ignored
ORA-06550: line 8, column 2:
PLS-00320: the declaration of the type of this expression is incomplete or malformed
ORA-06550: line 8, column 2:
PL/SQL: Statement ignored
ORA-06550: line 9, column 2260:
PLS-00320: the declaration of the type of this expression is incomplete or malformed
ORA-06550: line 9, column 2:
PL/SQL: Statement ignored
  DAD name: portal30
  PROCEDURE  : PORTAL30.wwv_edit_tab.edititem
  URL        : http://HDESCHAM-LAP:80/pls/portal30/PORTAL30.wwv_edit_tab.edititem

Hervé Deschamps is a Technical Manager with Oracle Corporation. Over the years he has developed a number of applications using Oracle Development Tools and others.  He has an extensive experience of all phases of the development life cycle. He is also known in the technical community for his article publications centered around best custom development practices and for his user group presentations. You can reach him by e-mail at herve.deschamps@.oracle.com. He also maintains a web site full of articles, scripts, tips and techniques at http://www.iherve.com.