Getting types of the attributes in an ActiveRecord object

In Rails 3, for your model "Driver", you want Driver.columns_hash.

Driver.columns_hash["name"].type  #returns :string

If you want to iterate through them, you'd do something like this:

Driver.columns_hash.each {|k,v| puts "#{k} => #{v.type}"}

which will output the following:

id => integer
name => string
created_at => datetime
updated_at => datetime

In Rails 5, you can do this independently of the Database. That's important if you use the new Attributes API to define (additional) attributes.

Getting all attributes from a model class:

pry> User.attribute_names
=> ["id",
 "firstname",
 "lastname",
 "created_at",
 "updated_at",
 "email",...

Getting the type:

pry> User.type_for_attribute('email')
=> #<ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter::MysqlString:0x007ffbab107698
 @limit=255,
 @precision=nil,
 @scale=nil>

That's sometimes more information than needed. There's a convenience function that maps all these types down to a core set (:integer, :string etc.)

> User.type_for_attribute('email').type
=> :string 

You can also get all that data in one call with attribute_types which returns a 'name': type hash.

You can access the types of the columns by doing this:

#script/console
Driver.columns.each {|c| puts c.type}

If you want to get a list of all column types in a particular Model, you could do:

Driver.columns.map(&:type) #gets them all
Driver.columns.map(&:type).uniq #gets the unique ones

In rails 5 this will give you a list of all field names along with their data type:

Model_Name.attribute_names.each do |k| puts "#{k} = #{Model_Name.type_for_attribute(k).type}" end