Rails Migration sample

Migration_sample.md

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

Sample

bin/rails g model Supplier name:string
bin/rails g model Product name:string:index sku:string{10}:uniq count:integer description:text supplier:references popularity:float 'price:decimal{10,2}' available:boolean availableSince:datetime image:binary
bin/rails g model invoice data_paid:datetime invoice_number:uniq fee:decimal{8.2} tax:decimal{8.2} total_amout:decimal{8.2} payment_type:integer site:references
bin/rails g scaffold Article title images:attachments