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How Are Students Learning Programming ?

A recent ComputerWorld article "How are students learning programming in a post-Basic world ?" (It should be BASIC, not Basic) reminds me of the time I first learnt programming.

Yes, with BASIC. When there were very few PCs in Ahmedabad.

Oracle APAC Developer Program

Oracle ACEs in this part of the world had a conference call with Oracle's Program Executive for the APAC Developer Program.

We were provided information about forthcoming DBA Round Table and Developer Day sessions. We were also given assurances that Oracle would continue supporting the ACE program and members.
Thank you, Shaheen.

OOW 2011 Content Catalog

The Oracle Open World 2011 Content Catalog is now available for viewing.


Inequality and NULL

A response recent forums question about handling an inequality condition also reminded me, once again, about NULL handling in Oracle.

You can have :

WHERE column = 100 

in a query.

In another query, you could have

WHERE column != 100 

However, if the column does contain a NULL in any one (or more rows), the union of the two queries is not the entire table. That is, rows with NULLs are excluded.
You have to specifically handle NULLs with either

SQL Injection

Here's a very simple example of SQL Injection by Mike Smithers.


New Presentation : On Nested Loop and Hash Join

I have uploaded a new presentation on Nested Loop and Hash Joins. This is based on the "Nested Loops and Consistent Gets" case study.


Getting the right statistics

Continuing with the post titled "Nested Loops and Consistent Gets" earlier today, what is the Execution Plan with statistics on more columns ?

SQL> exec dbms_stats.gather_table_stats('','TRANSACTIONS',estimate_percent=>100,granularity=>'ALL',-
> method_opt=>'FOR COLUMNS COUNTRY_CD SIZE 250, PRODUCT_CD SIZE 250, TXN_ID SIZE 250 ',cascade=>TRUE);

PL/SQL procedure successfully completed.


Nested Loop and Consistent Gets

DBAs with a few years of experience and/or having read some material on performance tuning know that eliminating physical reads and achieving a high buffer cache hit ratio isn't necessarily a tuning goal.
Some DBAs have accepted the idea that, rather than physical reads, they should concentrate on logical reads -- consistent gets in case of queries.
But ...... there really is no "absolutely correct optimization target". Everything is relative.

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