Refresh Multiple Materialized Views in One Go: No Data Found

To refresh multiple Materialized Views you can use the DBMS_MVIEW package, with the procedure aptly named Refresh. One method is to provide a comma-separated list of Materialized View names, or you can use an DBMS_UTILITY.UNCL_ARRAY to achieve the same objective.
When using the latter method, I stumbled upon this oddity (which is not in the current documentation, or at least I couldn't find it).

The procedure that I initially wrote was the following:

create (more...)

Speed Up Development with Logger: Generate a Template

Instrumentation of PL/SQL code is essential. My favourite tool to instrument PL/SQL is Logger.
Martin Giffy D'Souza wrote a few blogs on how to speed up development with Logger and I want to chime in with my own productivity booster.
What I have written is a PL/SQL package that will generate a Procedure or Function body with all the calls to Logger. This includes all the arguments, or at least the IN and IN/OUT arguments.


In this post I will try to show you how I used the Oracle Apex and the APEX_WEB_SERVICE  PL/SQL package to quickly send a request to a public Internet API and how I handled the response. The code below was written during a 'Hackday' and hasn't been extensively tested.

My use case is integrating Oracle Apex with the public Mendeley REST API for Mendeley Catalog Search.

The idea was to build an (more...)

APEX: Active Tabs Based on Page Groups

Recently someone asked me: "How did you do that? When I include an APEX page in a Page Group, the correct tab is automatically highlighted"
When I setup an application, I usually use Dimitri Gielis' method, so instead of using "real tabs", I use a List and display that list as Tabs.
For each of the "Tabs", I also create Page Groups, just to keep things organized.
Each of the List Entries will have a (more...)

Why is it not possible to raise an exception when handling no_data_needed ?

It seems impossible to raise an exception when handling no_data_needed.


create or replace function demo return sys.odciNumberList pipelined
  pipe row(1);
  pipe row(1/0);
exception when others then
  dbms_output.put_line('in exception handler, sqlcode: ' || sqlcode);
  raise program_error;

sokrates@11.2 > select * from table(demo());
ORA-06501: PL/SQL: program error
ORA-06512: at "SOKRATES.DEMO", line 8
ORA-01476: divisor is equal to zero

no rows selected

in exception handler, sqlcode: -1476

As (more...)

NYOUG Training Event: "High Performance PL/SQL" on Nov 7 2014

If you want to be able to create contemporary high-performing PL/SQL code, welcome to my training event in NYC (hosted by NYOUG) on November 7, 2014:

I think, it is as important as ever to follow best practices for server-side development. There are lots of options that could get the job done "now", but very few that would survive for months/years. Also, there is a constant pressure from various "alternative" solutions to (more...)

DBMS_REDACT and complete ROW update

My session on "Oracle 12c for Developers" is done.Afterwards someone asks the question:

What happens when you use DBMS_REDACT with a complete row update?
My guess was that it would place the redacted data in the column, but I haven't tried it, so here goes:

create table emp
select ename
,to_char (abs (dbms_random.random)) credit_card
from scott.emp

(object_schema => 'A'
,object_name => 'EMP'
,policy_name => 'Hide Creditcard'
,expression (more...)

My new book

It seems to me that I talked about my most recent book everywhere except for my own blog... So, let me introduce you a one and only performance tuning book dedicated to PL/SQL:

This book took me much longer to write than I initially anticipated - and to be fair, that's the reason for staying quiet at the blog. I just didn't have time/energy to write everywhere :-) Although, it was fun writing - (more...)

Time to resurrect blogging!

Sorry for staying quiet for some time, but for some good reasons. Some of these reasons will be explained in later posts, but for now I would like to share the story I wrote upon request of Steven Feuerstein, who asked to tell how PL/SQL impacted our life. Here is my story:

I started to work with databases already in college, but more from the data modelling/business analysis angle. When I moved to (more...)

★ Database as a Storage (DBaaS) vs. Thick Database

A recent addition to my Oracle PL/SQL library is the book Oracle PL/SQL Performance Tuning Tips & Techniques by Michael Rosenblum and Dr. Paul Dorsey.

I agree with Steven Feuerstein’s review that “if you write PL/SQL or are responsible for tuning the PL/SQL code written by someone else, this book will give you a broader, deeper set of tools with which to achieve PL/SQL success”.

In the foreword of the book, Bryn Llewellyn writes:

The (more...)

Avoid UTL_FILE_DIR Security Weakness – Use Oracle Directories Instead


The UTL_FILE database package is used to read from and write to operating system directories and files. By default, PUBLIC is granted execute permission on UTL_FILE. Therefore, any database account may read from and write to files in the directories specified in the UTL_FILE_DIR database initialization parameter [...] Security considerations with UTL_FILE can be mitigated by removing all directories from UTL_FILE_DIR and using the Directory functionality instead.

© Eddie Awad's Blog, (more...)

New in Oracle 12c: Querying an Associative Array in PL/SQL Programs

I was aware that up to Oracle 11g, a PL/SQL program wasn’t allowed use an associative array in a SQL statement. This is what happens when I try to do it.

SQL> drop table test_array purge;

Table dropped.

SQL> create table test_array as
  2  select level num_col from dual
  3  connect by level <= 10;

Table created.

SQL> select * from test_array;


10  (more...)

Are You Using BULK COLLECT and FORALL for Bulk Processing Yet?

Steven Feuerstein was dismayed when he found in a PL/SQL procedure a cursor FOR loop that contained an INSERT and an UPDATE statements.

That is a classic anti-pattern, a general pattern of coding that should be avoided. It should be avoided because the inserts and updates are changing the tables on a row-by-row basis, which maximizes the number of context switches (between SQL and PL/SQL) and consequently greatly slows the performance of the code. Fortunately, (more...)

PL/SQL oddity

sokrates@12.1 > create procedure p is begin null; end this_does_not_compile;
  2  /

Warning: Procedure created with compilation errors.

sokrates@12.1 > show errors
Errors for PROCEDURE P:

-------- -----------------------------------------------------------------
1/32	 PLS-00113: END identifier 'THIS_DOES_NOT_COMPILE' must match 'P'
	 at line 1, column 11

sokrates@12.1 > REM expexted
sokrates@12.1 > create function f return number is begin return null; end this_does_not_compile;
  2  /

Warning: Function created with compilation errors.

sokrates@12.1 >  (more...)

PL/SQL, UTL_HTTP and Digest Authentication

For the first time in what seems like ages, I've actually put together a piece of code worth sharing. It's not that I haven't been working, but just that it has all been very 'in-house' specific.

However I had a recent requirement to use a web service that makes use of Digest Authentication. If you have look at the UTL_HTTP SET_AUTHENTICATION subprogram, it only addresses Basic authentication (and, apparently, Amazon S3 which looks intriguing).

In (more...)

Readable Code for Modify_Snapshot_Settings

It annoyed me slightly that when I googled modify_snapshot_settings just now and all of the examples used huge numbers for the retention with (at best) a brief comment saying what the number meant. Here is a better example with slightly more readable code. Hope a few people down the road (more...)

Oracle 12c OFFSET…FETCH.. bug?

Working on the chapter that covers best ways of manipulating with object collection. Of course, if you talk about pagination of the rowset, it is very tempting to test Oracle 12c new feature - OFFSET…FETCH.

Unfortunately, immediately got an issue. It seems to me that passing a variable to FETCH (more...)


Over the weekend one of my friends asked me for a clarification on RESULT_CACHE - a really interesting functionality that allows Oracle to cache in SGA results of PL/SQL function calls.

The point of confusion was the fact that between 11gR1 and 11gR2 Oracle development team significantly re-thought this feature (more...)

Performance tuning. Spending time is NOT OK (if you do not know exactly why)

Yet another performance tuning story, similar to one that happened about a month ago. Just to keep it short:

  • once upon a time there was a very time-consuming module.
  • eventually we were forced to take much closer look - WHY is it so time-consuming
  • we found in our own (more...)

Oracle Internals. Digging out PL/SQL fine-grain dependencies

After a couple of requests at IOUG Collab'13 I decided to resurrect a pretty old topic that I've participated in 2008 (since in 5 years there was no changes on that front :-) ).

As we all know, starting version 11g Oracle tracks PL/SQL dependencies in much more granular way (more...)