fodra

1. Remove all untracked git files

$ git clean -fd

2. View all tags

$ git tag

3. Undo last commit

fodra

// sleep using promise
function sleep(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
}

fodra

1. One-to-Many or Many-to-One relationships

• One gets no field
• Many gets the ForeignKey field

class One(models.Model):
  pass
  
class Many(models.Model):

fodra

1. Create a copy of a database

$ createdb -O <owner> -T database_to_copy new_database

2. Create a database

$ createdb -O <owner> database_name

fodra

1. Create an empty django migration

python manage.py makemigrations --empty yourappname

2. Show applied migrations

python manage.py showmigrations <app_name>

3. Rollback migration to a specific state

fodra

# Shortcuts for doing stuff in gametraka_project_v3

.PHONY : clean help build redisq gui devdeps dev clean run requirements test

help:
	@echo "lint - check style with flake8 and isort"
	@echo "devdeps - runs rqworker and gui front-end"
	@echo "dev - runs gametraka on localhost"
	@echo "test - runs test suite"
	@echo "clean - deletes temporary files"

fodra

-- get the 10 most recent sold listings for the specific agency
SELECT id, status, sold_price, sold_date 
FROM listings_listing 
WHERE agency_id = '3ab9adc2-7fd2-4b24-8cd0-d0cc69270fbf' AND status = 'S' 
ORDER BY sold_date DESC LIMIT 10;

-- modify the query set to a new date somewhere between now and four weeks ago
UPDATE listings_listing
SET sold_date = now(),
	source_type = 'M'

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Joins

Retrieve the start times of members' bookings

The main thing here is the bit where you rename the table to something shorter: cd.members > mem. However this site clearly doesn't do that.

The concept is simple enough, you just have to join two tables that are related via a foreign key. When you join them together, you get a more detailed row.

fodra

Basic

Retrieve everything from a table

select * from cd.facilities;

Retrieve specific columns from the table

select name, membercost from cd.facilities;

fodra

function deepCopy(obj) {
  return new Promise(resolve => {
    const {send, recv} = new MessageChannel();
    recv.onmessage = ev => resolve(ev.data);
    send.postMessage(obj);
  });
}

const obj = /* object to copy */;
const clone = await deepCopy(obj);