Rails Project-Blogger Problem

Ran into my first challenge with the blogger today. I was creating a new model for a Comment feature and I typed:

$ bin/rails generate model Comment author_name:string body:text articles:references

That single red letter cost me an hour of struggle (I mean 'learning'). The extra s created a database schema containing something called 'articles_id'.

Since id is a property of a single article, the comment controller couldn't find an id for articles, as it didn't exist.

I looked at the Comment model file and saw the extra s almost immediately after trying to enter a comment. But then I couldn't reverse the error.

Rolling back the migration (rake db:rollback), had no effect on the schema.

Destroying the model (rails destroy model Comment) had no effect on the schema.

In the end I replaced the my local files with the Github repo contents (luckily I had just done a push).

git fetch --all
git reset --hard origin/master

THEN, I recreated the correct model, ran the migration and reset the database

(rake db:reset).

Unfortunately, this meant I lost the five beautifully written articles I had stored in the first database. Perhaps I didn't need that db:reset?

Comments

Einstein's Logic Puzzle (SPOILER ALERT!)

On Monday I began working through a Discrete Math textbook in preparation for some courses I'll be taking in January. There was a beautiful logic problem in Chapter 1, apparently created by Einstein. This is one version of it: Five men with different nationalities and with different jobs live in con secutive houses on a street. These houses are painted dif ferent colors. The men have different pets and have dif ferent favorite drinks. Determine who owns a zebra and whose favorite drink is mineral water (which is one of the favorite drinks) given these clues: The Englishman lives in the red house. The Spaniard owns a dog. The Japanese man is a painter. The Italian drinks tea. The Norwegian lives in the first house on the left. The green house is immediately to the right of the white one. The photogra pher breeds snails. The diplomat lives in the yellow house. ...

Venturing into Number Theory

In attempt to solve a maths problem with Ruby, I discovered the benefits of going beyond simple arithmetic. Perhaps surprisingly, many seemingly complex mathematical problems can be solved using basic arithmetic and raw computing power. Most of the time this doesn't pose a problem. However, as the values involved grow larger, the demands on the computer's memory reaches a critical point beyond which you risk crashing your computer. The problem I was trying to solve was the following: What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20? After causing my computer to hang for several minutes, I realized I had to rewrite the program I was working on. The program had to take shortcuts, so that instead of testing every single value between 1 and 1 million, it only tested likely values. With the help of my lovely wife (a Maths teacher) I rewrote the program using prime numbers. class SmallestProduct requ...

CodeSchool vs Codecademy(or 'How socket inherits event listening methods and implements asynchronicity')

In this review I'm going to focus on the pedagogy that I see evident in some CodeSchool courses and compare them to Codecademy. By pedagogy, I mean: 'How does CodeSchool teach?' and ' Does it do a good job of teaching?'. I'm going to argue that despite high quality videos, colourful web pages, and often ssspppeeeeeakkkiiiing...rrrreeally...slowly..., CodeSchool's pedagogy is inferior to that of Codecademy. There are many fantastic resources for learning to code on the web, and CodeSchool is one of them. So far I have completed courses in Ruby, Rails, Javascript, HTML/CSS, Jquery and Git on CodeSchool. The courses have all included high quality videos and colourful, interactive exercises- as well as massive pdf files of the slides ( the files take more than a minute to load on my machine .) The question is: does the higher production value mean better educational quality? The 'Try' courses on CodeSchool(such as Try Ruby and Try jQuery) are f...

Programming on the Wall

Search This Blog