PostgreSQL's array data type is pretty useful, but manipulating values of arrays can be awkward because of its syntax.

Consider the following users table which each example below will sta...

The way Rational#to_s works on Ruby has changed from Ruby 1.9 on. Here is how to get the old behavior back.

You may want this for things where Rationals are being used, like when subtracting Date objects from one another.

What's happening?...

Bundler

bundle outdated [--filter-major|--filter-minor|--filter-patch]

Example output for bundle outdated --filter-major

Other examples

A useful flag is --strict as it wi...

The way MySQL's FULLTEXT tokenizer splits text into word tokens might not always be what you need. E.g. it splits a word at period characters.

Since the tokenizer has near-zero configuration options (minimum word length and stopwords list), you n...

It's generally not trivial to change a datetime's seconds, minutes, etc in SQL. Here is how it works when speaking PostgreSQL.

Consider you have a timestamp column whose seconds you want to zero:

SELECT born_at FROM users;
       born_at...

When you want to UPDATE a table with information from an associated table, you can JOIN the associated table into the statement.

Example

Let's say you have a database schema where an Employee belongs_to :department:

+-----...

If you want to prevent that two processes run some code at the same time you can use the gem with_advisory_lock.

What happens

1. The thread will wait indefinitely until the lock is acquired.
   ...

Remember why preloading associations "randomly" uses joined tables or multiple queries?

If you don't like the cleverness of thi...

Rails 5 / 6 / 7

| Method | Uses Default Accessor | Saves to Database | Runs Validations | Runs Callbacks | Updates updated_at/updated_on | Respects Readonly |
|-------------------|-----------------------|-------------------|---------...

Given the problem you have a new column postion and that column should be updated for all existing rows with ascending numbers. Furthermore these numbers should be generated by a special order. In order to achieve that you could do the fol...