In this second part of a four-part article series on building a basic Ruby-on-Rails application, you will learn how to create both a database and the event model. This article is excerpted from chapter three of the book Beginning Rails: From Novice to Professional, written by Jeffery Allan Hardy, Cloves Carneiro Jr. and Hampton Catlin (Apress; ISBN: 1590596862).
Database for a Ruby-on-Rails Application - Creating the Event Model (Page 2 of 2 )
Now that we can connect to the database, we’re going to create a model. Remember that models in Rails correspond to database table names. Since we want to model events, we’re going to create a model named Event. By convention, model names are singular and correspond to plural table names. So, anEventmodel will expect a table namedevents; aPersonmodel will expect a table namedpeople.
Like most things in Rails, models have their own generator script that makes it easier to get started. The generator will automatically create a new model file in theapp/modelsdirectory, and will create a bunch of other files to boot. Among these are a unit test (for testing your model’s functionality, as we’ll discuss in Chapter 9) and a database migration. A database migration contains instructions for building the database table and the fields to create. Whenever you generate a new model, a migration will be created along with it.
Note If you want to skip generation of the migration when generating a new model, you can pass the--skip-migration argument to the generator.
To see the generator’s usage information, run it without arguments.
$ ./script/generate model
-------------------------------------------- Usage: ./script/generate model ModelName [options] --------------------------------------------
As you can see from the usage banner, the generator takes a model name as its argument. The model name may be given in CamelCase or under_score format, and options can be provided if you want to automatically populate the resulting migration with column information.
Let’s run the generator now to create our first model:Event.
If you look at the lines that start withcreate, you’ll see that the generator created an event model, an event test, an events fixture (which is a textual representation of table data that you can use for testing), and a migration named001_create_events.rb. With that, our model is generated.
Please check back for the continuation of this article.
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