My father, Sheldon Feuerstein, was a large presence in our lives and the lives of many others. He was a big man, physically (and, sadly, overweight for too many of his later years, which contributed to the diseases that led to his death in 2010), but it was more than that. He was smart and honest and eloquent. He could also be very stern and, before he passed middle age, manifested quite the temper. But he was a deeply compassionate man, especially for members of the family. Many nieces, nephews and cousins remember him with a love and deep fondness that sometimes surprises me.
where understanding_of_venn_diagrams = 'Y'
where understanding_of_sql = 'Y';
People who understand this is
a Venn diagram in disguise
select posts from sqlfail
My students required way to remove all their tables, views, and constraints from a MySQL
database (or the alias
schema). Since they’re using referential or foreign key constraints, I also wrote one procedure to drop all foreign key constraints from a database. There’s also another to drop views. The final stored procedure calls the procedure that drops foreign keys, then calls the procedure to drop views before dropping all the tables.
dropForeignKeys stored procedure:
In teaching, I had a problem because my students have different base operating systems, like Windows 7, Windows 8, Linux, and Mac OS X. I needed a teaching and lecture platform that would let me teach it all (not to mention support their environments).
when others then
dbms_output.put('Just ignore it...');
dbms_output.put('...it'll go out soon!');
This is a re-hash of my very first post. I wouldn’t normally repeat myself, but I’ve just been horribly burned by some code with “when others then null” blocks.
While you try to eliminate all errors when you write a book, some exceptions remain and some new opportunities present themselves. I think we did a great job on this book and the errors are minimal, but readers bring new insights and rereading what you’ve written brings fresh ideas. This errata includes corrections of mistakes, suggestions for change, and improvements to the base text. If the book is successful, I’m sure they’ll make it into the next edition.
An SQL magic trick – the table disappeared, just by running a select statement! Can you figure out how it’s done?
Now you don't
ORA-00942: table or view does not exist
If you think you know, put your answers in the comments!
I received this very pleasant note today from a PL/SQL developer:
In the database design quiz on the PL/SQL Challenge, a player made a comment referring to a 5% rule for indexes – i.e. that an index will (only) be used when accessing 5% or less of the rows in a table. This is something I’ve heard others refer to as well, so I thought I’d put together a post explaining how indexes work via the medium of chocolate!