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Accessing column information with ActiveRecord

A quick tip - ActiveRecord provides a number of methods that allow you to access information about the underlying table columns for a model.

columns

Returns an array of Column objects.

columns_hash

Similar to the columns method but returns a Hash using column names as keys and Column objects as values.

column_names

Returns a simple array of column names for the model.

The Column objects returned by columns and columns_hash can then be used to get information such as the data type and default values, for example:

User.columns_hash['email'].type
=> :string
User.columns_hash['email'].default
=> nil
User.columns_hash['email'].sql_type
=> "varchar(255)"