Flowdock
method

column_exists?

Importance_2
Ruby on Rails latest stable (v4.0.2) - 2 notes - Class: ActiveRecord::ConnectionAdapters::SchemaStatements
column_exists?(table_name, column_name, type = nil, options = {}) public

Checks to see if a column exists in a given table.

# Check a column exists
column_exists?(:suppliers, :name)

# Check a column exists of a particular type
column_exists?(:suppliers, :name, :string)

# Check a column exists with a specific definition
column_exists?(:suppliers, :name, :string, limit: 100)
column_exists?(:suppliers, :name, :string, default: 'default')
column_exists?(:suppliers, :name, :string, null: false)
column_exists?(:suppliers, :tax, :decimal, precision: 8, scale: 2)
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January 20, 2012
1 thank

Example

Check if id column exists in users table

ActiveRecord::Base.connection.column_exists?(:users, :id)
February 20, 2013
0 thanks

It also works with strings

It works with strings:

ActiveRecord::Base.connection.column_exists?('users', 'id')

Which is helpful if you need to specify the database/schema to use:

ActiveRecord::Base.connection.column_exists?('secondary.users', 'id')