Two small things I learn today

Today I learned that there is always something that we don't know, even in our main activity area.

1- In Oracle it's possible to make columns unavailable to normal use (SQL statements, etc..) without dropping them! So we could make a column "unavailable"
alter table mytable set unused column mycolumn;
test all the code and only later dropping it
alter table mytable drop unused mycolumn;

2- HTML has a tag button that makes possible to have buttons with images and text (besides the use of CSS classes).
Notice to myself: replace all the forms 'input type="submit" ' buttons to 'button type="submit"'

Of course that there is lots of stuff to learn about ORACLE but I was really surprised to find out that HTML tag!
Ok ...that tag only appeared in HTML 4.0 but that was almost 10 years ago! ops ...i'm getting old!