This Week I Learned 2018 - Week 14

Something from the archive or last week post.

We have been doing blood pressure measurement wrongly for all this while. You must measure blood pressure from both arms. Yes, both arms and find the differences. According to Harvard Health,
"A blood pressure difference of 10 to 15 points or more between arms also boosted the chances of having a stroke or dying from cardiovascular disease. "
Personal data and GDPR: practical guide for developers. Shaking my head while reading through the whole post. I was wondering how a software team going to ensure data anonymization in development environment when handling production data? When come to this, the US/Canada software houses are doing a better job than the EU/Asia counterpart.

What if we apply this to our life instead? Rearrange your line of thoughts in your writing. Intriguing discussion when come to writing.


"The Surgical Team" (chapter 3 in the infamous book, The Mythical Man-Month), a different software development team structure which it's similar to the surgery team where,
"The idea was to construct development teams in a way similar to the surgery teams - one lead developer, one assistant developer (these two "adult" and very good), and a 3-4 other people who 's job is to make the life easier for the main devs - someone to manage documentation, someone else to do detailed testing, one average dev to do the simple and boring stuff, and so on."
Maybe an alternative approach where the Agile methodology like Kanban or Scrum cannot be applied successfully or productively. Why so? Cargo cult software engineering, as coined by Steve McConnell where software development houses try to imitate successful processes or approaches without understanding why such methodologies works for them. What works well (may due to luck and timing) for an organization or team may not be suitable for another organization or team. Don't uses Scrum for the sake of using Scrum. Another good example, the reinventing of office space, open office, pool table, ping pong table, gaming corners, and the like. Yes, the startups starter pack.

Fork and Pull Request Workflow. While version control system have been available since the 70s, till today, amazingly, some companies still refuse or slow to adopt it. Everyone have their own workflow and branching models.

Quite a number of MySQL Gotchas this week. Fair enough, it will happen to any of the DBMS out there. My tolerance towards MySQL have increased along these years. Must be something to do with getting old.

How do you order a list of items where the NULL data is at the bottom of the list? It's actually quite easy, just use ORDER BY ISNULL. See the example below.
SELECT * FROM table ORDER BY ISNULL(field), field ASC;

NULL, NULL, NULL, 1, 2, 3, 4
1, 2, 3, 4, NULL, NULL, NULL

Creating a function in MySQL. That was rare but somehow we may need it to reduce or shorten the SQL query. Yet, we kept encounter this idiotic error of "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DELIMITER |' at line 1". Just add a BLOODY space! Yes, a BLOODY space before the semicolon!
DELIMITER //
Create function or procedure
Write your function or procedure here...
End (without semicolon)
//
DELIMITER ; (semicolon with space)

Write UPDATE SQL query with multiple joins and SUB-SELECT but the query won't work in SUB-SELECT? Wrap the SUB-SELECT condition with one more join!
DELETE FROM story_category
WHERE category_id NOT IN (
    SELECT cid FROM (
        SELECT DISTINCT category.id AS cid FROM category
        INNER JOIN story_category ON category_id=category.id
    ) AS c 
)

How many ways to insert a not found record in MySQL? Plenty of ways. Not sure these works cross database systems.

Career do-over? Either moving to management and if you don't like it, restart your development career again.


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