Wednesday May 30, 2012

Summer Upgrade Workshops are Open!

The listing of upcoming events is located in the right sidebar of the main blog page, down below the flag counter. If you haven't checked out our schedule lately, you might be surprised at how active we will be with travel this summer. Coming up next week will be upgrade workshops in the USA (St. Louis and Minneapolis) followed by a pair in Canada (Toronto and Montreal) and then two in Europe (Brussels and Utrecht).

June 2012 Workshop locations

Make your plans now to attend an upgrade workshop in your area. As you can see from the long list of planned events, it is very likely that Mike or I will be coming to your area sometime soon!

Tuesday May 29, 2012

Please use the new HTML Support Portal interface

It has taken a while ... ;-) But finally Oracle Support is switching the My Oracle Support Portal (MOS) from Flash to HTML. So please when you log in use the switch for HTML. 

If you'd like to get further information on changes, differences and such please see the following content:

 - Mike

Friday May 11, 2012

NLS_LENGTH_SEMANTICS - Why not in the init.ora?

.Few days ago at the Upgrade and Migration Workshop in Hamburg when I did talk about Unicode Migrations a customer had an interesting question.

"Why does the documentation states NOT to set NLS_LENGTH_SEMANTIC parameter to CHAR in the init.ora/spfile to enable char semantics for newly build objects by default?"

Honestly I was not aware of that hint. So I did some research and tried to get an answer from the developers.

The documentation says clearly not to set that parameter permanently:

  • Oracle Database Reference on NLS_LENGTH_SEMANTICS
    • Caution:
      Oracle strongly recommends that you do NOT set the NLS_LENGTH_SEMANTICS parameter to CHAR in the instance or server parameter file. This may cause many existing installation scripts to unexpectedly create columns with character length semantics, resulting in runtime errors, including buffer overflows.

  • Oracle Database Globalization Support Guide on NLS_LENGTH_SEMANTICS
    • Same warning as above - but also states:
    • NLS_LENGTH_SEMANTICS does not apply to tables created in the SYS schema. The data dictionary always uses byte semantics. Tables owned by SYS always use byte semantics if the length qualifier BYTE or CHAR is not specified in the table creation DDL.

And my colleague from Poland, Sergiusz Wolicki did reply (as always) very quickly (thanks!!!):

"The warning is general as the problem may affect Oracle data dictionary scripts for schemas such as SYSTEM, CTXSYS, ORDSYS, XDB, SYSMAN, Oracle application scripts for schemas such as APEX_030000, APPL, APPLSYS, GL, and other eBS or Peoplesoft or JDE, but also third party prepackaged applications and customer's own legacy stuff.

The recommendation is to avoid the dependency on the parameter altogether
. The character and byte length semantics should be explicitly specified in column definitions and PL/SQL code:


CREATE TABLE emp( ..., first_name VARCHAR2(100 CHAR), last_name VARCHAR2(100 CHAR) )
/
CREATE PROCEDURE read_emp IS
  v_first_name emp.first_name%TYPE;
  v_last_name emp.last_name%TYPE;
  v_full_name VARCHAR2(202 CHAR);
BEGIN
  ...
  SELECT first_name, last_name INTO v_first_name, v_last_name FROM emp WHERE ...;
  v_full_name := v_last_name || ', ' || v_first_name;
END;
/

If you find specifying the data type and the length explicitly as an obvious thing, you should also expect that the length semantics (length units) are specified explicitly.

If you need to migrate existing scripts quickly, put an ALTER SESSION SET NLS_LENGTH_SEMANTICS=CHAR at the beginning of each script and after each CONNECT command in the script.
"

Thursday May 10, 2012

Upgrade Workshops in Hamburg and Cologne - Recap

Danke an alle Teilnehmer der Upgrade & Migration Workshops in Hamburg und Köln. Und noch einmal eine grosse Entschuldigung wegen der falschen Event-Adresse im Web beim Hamburger Workshop, den dadurch bedingten etwas späteren Beginn und die natürlich die daraus entstandenen Unannehmlichkeiten.

Von meiner Seite ein grosser Dank für die tolle Athmosphäre an beiden Workshop-Tagen, Ihre Fragen und Ihr Feedback. Die Slides finden Sie, wie angekündigt, rechts im Slide Download Center :-)


Wednesday May 02, 2012

Behaviour Changes Oracle 8i to 11.2 + New Features Oracle 11.2 + refreshed Upgrade and Migration Slides

We have uploaded refreshed and new slide sets:

About

Mike Dietrich - Oracle Mike Dietrich
Senior Principal Technologist - Database Upgrade Development Group - Oracle Corporation

Based near Munich/Germany and spending plenty of time in airplanes to run either upgrade workshops or work onsite with reference customers. Acting as interlink between customers and the Upgrade Development.

Contact me either via XING or LinkedIn

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