method

update

v7.1.3.2 - Show latest stable - 0 notes - Class: ClassMethods

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What's this?

update(id = :all, attributes) public

Updates an object (or multiple objects) and saves it to the database, if validations pass. The resulting object is returned whether the object was saved successfully to the database or not.

Parameters

id - This should be the id or an array of ids to be updated. Optional argument, defaults to all records in the relation.
attributes - This should be a hash of attributes or an array of hashes.

Examples

# Updates one record
Person.update(15, user_name: "Samuel", group: "expert")

# Updates multiple records
people = { 1 => { "first_name" => "David" }, 2 => { "first_name" => "Jeremy" } }
Person.update(people.keys, people.values)

# Updates multiple records from the result of a relation
people = Person.where(group: "expert")
people.update(group: "masters")

Note: Updating a large number of records will run an UPDATE query for each record, which may cause a performance issue. When running callbacks is not needed for each record update, it is preferred to use {update_all}[rdoc-ref:Relation#update_all] for updating all records in a single query.

Show source

# File activerecord/lib/active_record/persistence.rb, line 408
      def update(id = :all, attributes)
        if id.is_a?(Array)
          if id.any?(ActiveRecord::Base)
            raise ArgumentError,
              "You are passing an array of ActiveRecord::Base instances to `update`. "                "Please pass the ids of the objects by calling `pluck(:id)` or `map(&:id)`."
          end
          id.map { |one_id| find(one_id) }.each_with_index { |object, idx|
            object.update(attributes[idx])
          }
        elsif id == :all
          all.each { |record| record.update(attributes) }
        else
          if ActiveRecord::Base === id
            raise ArgumentError,
              "You are passing an instance of ActiveRecord::Base to `update`. "                "Please pass the id of the object by calling `.id`."
          end
          object = find(id)
          object.update(attributes)
          object
        end
      end

update

Related methods

Parameters

Examples