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!
I’ve not been too well recently, so to “celebrate” here’s six SQL clues to various diseases. Can you get them all? Put your answers in the comments!
The following players will be invited to participate in the Q4 2013 championship. The number in parentheses after their names are
the number of playoffs in which they have already participated.
Congratulations to all listed below on their accomplishment and best of luck in the upcoming competition!
currently plan to hold the championship on 27 February (all at the same time world-wide), and are waiting for confirmation from players that this day will work.