Gunnar's blog - TIL

Disable Atom.js Startup Welcome Guide

There is a discreet checkbox at the bottom of the left hand block of text that disable the Atom.js startup Welcome Guide

I've been test driving Atom.js and I like it pretty well. Something I don't like about it, is that the startup welcome guide keeps coming back. After several days of using it, I finally noticed how to turn it off.

In the left hand pane, at the bottom of the text there is a checkbox that disables the Welcome Guide. I think it's pretty hard to see, at least with the dark theme, but just uncheck it and you are good to go.

TIL CSS has a 'Calculate' Function

I don't like to specify layouts in pixels, because display sizes are all over the place. I dislike sniffing the display size and adjusting parameters through javascript, because I feel like the document should take care of all of that for me.

Something that has been bothering me is I find myself specifying heights, widths, margin, etc in em, while I typically specify border in px. Maybe this is bad practice, but it's what I've been doing.

The trouble is when trying to figure out how big something is, I can add up the em, and I can add up the pixels, but I didn't know how to combine them.

Today I learned that you can combine them with the calc() function. calc( 10em + 5px ); will spit out the number.

It's only supported in bleeding edge browsers, but it's a nice feature.

The big gotcha is that you must have a space surrounding the mathematical operator, or it won't get parsed.

Happy Calculating!

TIL SQL Unique Constraints can Apply to Multiple Columns

This is a little embarrassing, considering how long I've been working with SQL, but it's important to never stop learning.

Apparently, you can have a unique constraint that encompasses multiple columns. This is super useful!

I had a problem at work where I have two tables, a parent table

PARENT
--------------
ID

And a child table

CHILD
-------------
ID
PARENT_ID
NAME

I wanted to have each parent have children with unique names. Children don't need to have unique names - you might have a classroom full of Aidens, but every family only has one Aiden. I totally blanked on how to do this. I thought I probably had to craft a check constraint with a query that looked up the parent, but Stack Overflow to the rescue

You can just make a unique constraint that covers PARENT_ID and NAME at the same time

ALTER TABLE child ADD CONSTRAINT multi_unique UNIQUE (parent_id, name)

This probably saved future me from a real pain in the ass - I was worried I'd have to enforce this solely with business rules in the middle tier.

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