+++
date = "2015-11-27"
title = "Rails generate model: be specific"
tags = ["rails"]
description = "Rails offers some very useful generators, one of which creates new model, including migrations. But did you know you can get into the specifics right from the command line?"
slug = "rails-generate-model-be-specific"
+++

Rails can generate a lot of things for you. Personally I use `generate model` often to quickly setup a new model, including test files and a database migration.
In its simplest form it looks like this:

    rails generate product

This will get you started with a _naked_ `Product` model. To make things easier, you can also supply attribute names:

    rails generate product name description:text 

Optionally, you can tell the generator what _type_ of attribute you want. You can choose from the same types as you'd normally use in your migration:

 * `integer`
 * `primary_key`
 * `decimal`
 * `float`
 * `boolean`
 * `binary`
 * `string`
 * `text`
 * `date`
 * `time`
 * `datetime`

Now, that's not where it ends. Here are some more useful tricks:

### Associations

You can specify that your model _references_ another. Our `Product` might _belong_to_ a `Category`.

    rails generate product category:references

This generates the `category_id` attribute automatically. In some cases you might want to use a _polymorphic_ relation instead, no problem:

    rails generate product supplier:references{polymorphic}

### Limits

For `string`, `text`, `integer` and `binary` fields, you can set the limit by supplying it in curly braces:

    rails generate product sku:string{12}

For `decimal` you must supply two values for precision and scale:

    rails generate product price:decimal{10,2}

### Indices / Indexes

You can also set indices (unique or not) on specific fields as well:

    rails generate product name:string:index
    rails generate product sku:string{12}:uniq
    rails generate product supplier:references{polymorphic}:index

### Password digests and tokens

If you want to store password digests using `has_secure_password`, you can also use the `digest` type.

    rails generate user password:digest

And the same goes for `has_secure_token`.

    rails generate user auth_token:token

That's it. Happy generating.