tracks/vendor/rails/activemodel/lib/active_model/validations/uniqueness.rb
Luke Melia 901a58f8a3 Upgraded to Rails 2.1. This can have wide ranging consequences, so please help track down any issues introduced by the upgrade. Requires environment.rb modifications.
Changes you will need to make:

 * In your environment.rb, you will need to update references to a few files per environment.rb.tmpl
 * In your environment.rb, you will need to specify the local time zone of the computer that is running your Tracks install.

Other notes on my changes:

 * Modified our code to take advantage of Rails 2.1's slick time zone support.
 * Upgraded will_paginate for compatibility
 * Hacked the Selenium on Rails plugin, which has not been updated in some time and does not support Rails 2.1
 * Verified that all tests pass on my machine, including Selenium tests -- I'd like confirmation from others, too.
2008-06-17 01:13:25 -04:00

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Ruby

module ActiveModel
module Validations
module ClassMethods
# Validates whether the value of the specified attributes are unique across the system. Useful for making sure that only one user
# can be named "davidhh".
#
# class Person < ActiveRecord::Base
# validates_uniqueness_of :user_name, :scope => :account_id
# end
#
# It can also validate whether the value of the specified attributes are unique based on multiple scope parameters. For example,
# making sure that a teacher can only be on the schedule once per semester for a particular class.
#
# class TeacherSchedule < ActiveRecord::Base
# validates_uniqueness_of :teacher_id, :scope => [:semester_id, :class_id]
# end
#
# When the record is created, a check is performed to make sure that no record exists in the database with the given value for the specified
# attribute (that maps to a column). When the record is updated, the same check is made but disregarding the record itself.
#
# Because this check is performed outside the database there is still a chance that duplicate values
# will be inserted in two parallel transactions. To guarantee against this you should create a
# unique index on the field. See +add_index+ for more information.
#
# Configuration options:
# * <tt>:message</tt> - Specifies a custom error message (default is: "has already been taken")
# * <tt>:scope</tt> - One or more columns by which to limit the scope of the uniqueness constraint.
# * <tt>:case_sensitive</tt> - Looks for an exact match. Ignored by non-text columns (+false+ by default).
# * <tt>:allow_nil</tt> - If set to +true+, skips this validation if the attribute is +nil+ (default is: +false+)
# * <tt>:allow_blank</tt> - If set to +true+, skips this validation if the attribute is blank (default is: +false+)
# * <tt>:if</tt> - Specifies a method, proc or string to call to determine if the validation should
# occur (e.g. <tt>:if => :allow_validation</tt>, or <tt>:if => Proc.new { |user| user.signup_step > 2 }</tt>). The
# method, proc or string should return or evaluate to a true or false value.
# * <tt>:unless</tt> - Specifies a method, proc or string to call to determine if the validation should
# not occur (e.g. <tt>:unless => :skip_validation</tt>, or <tt>:unless => Proc.new { |user| user.signup_step <= 2 }</tt>). The
# method, proc or string should return or evaluate to a true or false value.
def validates_uniqueness_of(*attr_names)
configuration = { :message => ActiveRecord::Errors.default_error_messages[:taken] }
configuration.update(attr_names.extract_options!)
validates_each(attr_names,configuration) do |record, attr_name, value|
# The check for an existing value should be run from a class that
# isn't abstract. This means working down from the current class
# (self), to the first non-abstract class. Since classes don't know
# their subclasses, we have to build the hierarchy between self and
# the record's class.
class_hierarchy = [record.class]
while class_hierarchy.first != self
class_hierarchy.insert(0, class_hierarchy.first.superclass)
end
# Now we can work our way down the tree to the first non-abstract
# class (which has a database table to query from).
finder_class = class_hierarchy.detect { |klass| !klass.abstract_class? }
if value.nil? || (configuration[:case_sensitive] || !finder_class.columns_hash[attr_name.to_s].text?)
condition_sql = "#{record.class.quoted_table_name}.#{attr_name} #{attribute_condition(value)}"
condition_params = [value]
else
# sqlite has case sensitive SELECT query, while MySQL/Postgresql don't.
# Hence, this is needed only for sqlite.
condition_sql = "LOWER(#{record.class.quoted_table_name}.#{attr_name}) #{attribute_condition(value)}"
condition_params = [value.downcase]
end
if scope = configuration[:scope]
Array(scope).map do |scope_item|
scope_value = record.send(scope_item)
condition_sql << " AND #{record.class.quoted_table_name}.#{scope_item} #{attribute_condition(scope_value)}"
condition_params << scope_value
end
end
unless record.new_record?
condition_sql << " AND #{record.class.quoted_table_name}.#{record.class.primary_key} <> ?"
condition_params << record.send(:id)
end
results = finder_class.with_exclusive_scope do
connection.select_all(
construct_finder_sql(
:select => "#{attr_name}",
:from => "#{finder_class.quoted_table_name}",
:conditions => [condition_sql, *condition_params]
)
)
end
unless results.length.zero?
found = true
# As MySQL/Postgres don't have case sensitive SELECT queries, we try to find duplicate
# column in ruby when case sensitive option
if configuration[:case_sensitive] && finder_class.columns_hash[attr_name.to_s].text?
found = results.any? { |a| a[attr_name.to_s] == value }
end
record.errors.add(attr_name, configuration[:message]) if found
end
end
end
end
end
end