postgres jsonb_diff and array_unique

 I recently copypasted a couple of functions from stackoverflow for my prostgres projects that are worth mentioning, cause they show a pattern on how to write plpsql functions:

Clojure and aplisms

The more I do APL and K, the more I see forks and hooks everywhere else.

That's just a couple of little helpers I've added in some clojure projects. One is "apply-if", which more than from APL, I'm taking it from any procedural language, where you can do `x= if p(x) then f(x) else x`. We used to do this a lot in lua (using ands and ors). But in a combinator style.

Second one is an attempt at the fork pattern.

Look how the avg looks like. it's verbose, but it captures the idea very close to how APL does it.

2 classes of system designers

Here's a devastating quote from Andy Kinslow (NATO SOFTWARE ENGINEERING CONFERENCE ,1968) 

There are two classes of system designers. The first, if given five problems will solve them one at a time.

The second will come back and announce that these aren’t the real problems, and will eventually propose a solution to the single problem which underlies the original five.

This is the ‘system type’ who is great during the initial stages of a design project. However, you had better get rid of him after the first six months if you want to get a working system.

I found it in the Software Engineering conference pdf , but I didn't know anything about that "Andy Kinslow". And looking for that person, led me to some interesting findings, like an APL paper, or finding out that Andy Kinslow pioneered work on Time-Sharing-System, following leads of Corbato and Strachey

Copy table from another db in postgres

 This one is somehow a followup on "Duplicate row in plain sql". What I needed in this case was to copy 

Both dbs live in the same physical postgres, and the main user has rights over everything, so the process was painless, and took 5 minutes to set it up (accounting for reading the docs).

The trick is to use the postgres_fdw and create a schema "dev" inside db_test, so I can access the tables in db_dev.

Now you can easily do your  `insert into table_to_copy select * from dev.table_to_copy;`