MohamedAlaa

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

bretdavidson

anon       true, if the space may be omitted in anonymous function declarations
bitwise    true, if bitwise operators should be allowed
browser    true, if the standard browser globals should be predefined
cap        true, if upper case HTML should be allowed
continue   true, if the continuation statement should be tolerated
css        true, if CSS workarounds should be tolerated
debug      true, if debugger statements should be allowed
devel      true, if logging should be allowed (console, alert, etc.)
eqeq       true, if == should be allowed
es5        true, if ES5 syntax should be allowed

janikvonrotz

SQL languages

DDL is short name of Data Definition Language, which deals with database schemas and descriptions, of how the data should reside in the database.

DML is short name of Data Manipulation Language which deals with data manipulation, and includes most common SQL statements such SELECT, INSERT, UPDATE, DELETE etc, and it is used to store, modify, retrieve, delete and update data in database.

DCL is short name of Data Control Language which includes commands such as GRANT, and mostly concerned with rights, permissions and other controls of the database system.

Datatypes

Text types

ryanermita

Optimistic Locking assumes that a database transaction conflict is very rare to happen. It uses a version number of the record to track the changes. It raise an error when other user tries to update the record while it is lock.

usage

Just add a lock_version column to the table you want to place the lock and Rails will automatically check this column before updating the record.

Pessimistic locking assumes that database transaction conflict is very likely to happen. It locks the record until the transaction is done. If the record is currently lock and the other user make a transaction, that second transaction will wait until the lock in first transaction is release.

usage

zulhfreelancer

1. Assuming you have multiple Heroku apps and Git remote like so:

development https://git.heroku.com/xxx.git (fetch)
development https://git.heroku.com/xxx.git (push)
origin      [email protected]:xxx/xxx.git  (fetch)
origin      [email protected]:xxx/xxx.git  (push)
production  https://git.heroku.com/xxx.git (fetch)
production  https://git.heroku.com/xxx.git (push)
staging https://git.heroku.com/xxx.git (fetch)

eveningkid

How To Use React-Intl: internationalize your React app

This short tutorial assumes you know about ES6 syntax.

Get started

yarn add react-intl or npm i --save react-intl.

Create a messages file

This file should contain every message for your app.
It has an object of (locale, messages) couples:

jacksonpires

Rails 7 new features. Before and After

• Add ComparisonValidator
• PostgreSQL generated columns
• PostgreSQL custom enum types
• Add tracking of belongs_to association
• association_previously_changed? method
• Add invert_where method
• Add associated method
• Add missing method
• Active Record Encryption