### Home Classes Methods

### In Files

- lib/active_record/persistence.rb

### Namespace

- MODULE ActiveRecord::Persistence::ClassMethods

### Methods

- #becomes
- #decrement
- #decrement!
- #delete
- #destroy
- #destroyed?
- #increment
- #increment!
- #new_record?
- #persisted?
- #reload
- #save
- #save!
- #toggle
- #toggle!
- #touch
- #update_attribute
- #update_attributes
- #update_attributes!
- #update_column

### Files

- README.rdoc

### Class/Module Index

Quicksearch

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No matching classes.

# ActiveRecord::Persistence

# Active Record Persistence

### Public Instance Methods

becomes(klass) click to toggle source

Returns an instance of the specified `klass` with the attributes of the current record. This is mostly useful in relation to single-table inheritance structures where you want a subclass to appear as the superclass. This can be used along with record identification in Action Pack to allow, say, `Client < Company` to do something like render `:partial => @client.becomes(Company)` to render that instance using the companies/company partial instead of clients/client.

Note: The new instance will share a link to the same attributes as the original class. So any change to the attributes in either instance will affect the other.

    # File lib/active_record/persistence.rb, line 158
    def becomes(klass)
      became = klass.new
      became.instance_variable_set("@attributes", @attributes)
      became.instance_variable_set("@attributes_cache", @attributes_cache)
      became.instance_variable_set("@new_record", new_record?)
      became.instance_variable_set("@destroyed", destroyed?)
      became.instance_variable_set("@errors", errors)
      became.send("#{klass.inheritance_column}=", klass.name) unless self.class.descends_from_active_record?
      became
    end

decrement(attribute, by = 1) click to toggle source

Initializes `attribute` to zero if `nil` and subtracts the value passed as `by` (default is 1). The decrement is performed directly on the underlying attribute, no setter is invoked. Only makes sense for number-based attributes. Returns `self`.

    # File lib/active_record/persistence.rb, line 252
    def decrement(attribute, by = 1)
      self[attribute] ||= 0
      self[attribute] -= by
      self
    end

decrement!(attribute, by = 1) click to toggle source

Wrapper around `decrement` that saves the record. This method differs from its non-bang version in that it passes through the attribute setter. Saving is not subjected to validation checks. Returns `true` if the record could be saved.

    # File lib/active_record/persistence.rb, line 262
    def decrement!(attribute, by = 1)
      decrement(attribute, by).update_attribute(attribute, self[attribute])
    end

delete() click to toggle source

Deletes the record in the database and freezes this instance to reflect that no changes should be made (since they can't be persisted). Returns the frozen instance.

The row is simply removed with an SQL `DELETE` statement on the record's primary key, and no callbacks are executed.

To enforce the object's `before_destroy` and `after_destroy` callbacks, Observer methods, or any `:dependent` association options, use `#destroy`.

    # File lib/active_record/persistence.rb, line 117
    def delete
      if persisted?
        self.class.delete(id)
        IdentityMap.remove(self) if IdentityMap.enabled?
      end
      @destroyed = true
      freeze
    end

destroy() click to toggle source

Deletes the record in the database and freezes this instance to reflect that no changes should be made (since they can't be persisted).

    # File lib/active_record/persistence.rb, line 128
    def destroy
      destroy_associations

      if persisted?
        IdentityMap.remove(self) if IdentityMap.enabled?
        pk         = self.class.primary_key
        column     = self.class.columns_hash[pk]
        substitute = connection.substitute_at(column, 0)

        relation = self.class.unscoped.where(
          self.class.arel_table[pk].eq(substitute))

        relation.bind_values = [[column, id]]
        relation.delete_all
      end

      @destroyed = true
      freeze
    end

destroyed?() click to toggle source

Returns true if this object has been destroyed, otherwise returns false.

    # File lib/active_record/persistence.rb, line 58
    def destroyed?
      @destroyed
    end

increment(attribute, by = 1) click to toggle source

Initializes `attribute` to zero if `nil` and adds the value passed as `by` (default is 1). The increment is performed directly on the underlying attribute, no setter is invoked. Only makes sense for number-based attributes. Returns `self`.

    # File lib/active_record/persistence.rb, line 235
    def increment(attribute, by = 1)
      self[attribute] ||= 0
      self[attribute] += by
      self
    end

increment!(attribute, by = 1) click to toggle source

Wrapper around `increment` that saves the record. This method differs from its non-bang version in that it passes through the attribute setter. Saving is not subjected to validation checks. Returns `true` if the record could be saved.

    # File lib/active_record/persistence.rb, line 245
    def increment!(attribute, by = 1)
      increment(attribute, by).update_attribute(attribute, self[attribute])
    end

new_record?() click to toggle source

Returns true if this object hasn't been saved yet -- that is, a record for the object doesn't exist in the data store yet; otherwise, returns false.

    # File lib/active_record/persistence.rb, line 53
    def new_record?
      @new_record
    end

persisted?() click to toggle source

Returns if the record is persisted, i.e. it's not a new record and it was not destroyed.

    # File lib/active_record/persistence.rb, line 64
    def persisted?
      !(new_record? || destroyed?)
    end

reload(options = nil) click to toggle source

Reloads the attributes of this object from the database. The optional options argument is passed to find when reloading so you may do e.g. record.reload(:lock => true) to reload the same record with an exclusive row lock.

    # File lib/active_record/persistence.rb, line 287
    def reload(options = nil)
      clear_aggregation_cache
      clear_association_cache

      IdentityMap.without do
        fresh_object = self.class.unscoped { self.class.find(self.id, options) }
        @attributes.update(fresh_object.instance_variable_get('@attributes'))
      end

      @attributes_cache = {}
      self
    end

save(*) click to toggle source

Saves the model.

If the model is new a record gets created in the database, otherwise the existing record gets updated.

By default, save always run validations. If any of them fail the action is cancelled and `save` returns `false`. However, if you supply :validate => false, validations are bypassed altogether. See ActiveRecord::Validations for more information.

There's a series of callbacks associated with `save`. If any of the `before_*` callbacks return `false` the action is cancelled and `save` returns `false`. See ActiveRecord::Callbacks for further details.

    # File lib/active_record/persistence.rb, line 82
    def save(*)
      begin
        create_or_update
      rescue ActiveRecord::RecordInvalid
        false
      end
    end

save!(*) click to toggle source

Saves the model.

If the model is new a record gets created in the database, otherwise the existing record gets updated.

With `save!` validations always run. If any of them fail ActiveRecord::RecordInvalid gets raised. See ActiveRecord::Validations for more information.

There's a series of callbacks associated with `save!`. If any of the `before_*` callbacks return `false` the action is cancelled and `save!` raises ActiveRecord::RecordNotSaved. See ActiveRecord::Callbacks for further details.

    # File lib/active_record/persistence.rb, line 103
    def save!(*)
      create_or_update || raise(RecordNotSaved)
    end

toggle(attribute) click to toggle source

Assigns to `attribute` the boolean opposite of `attribute?`. So if the predicate returns `true` the attribute will become `false`. This method toggles directly the underlying value without calling any setter. Returns `self`.

    # File lib/active_record/persistence.rb, line 270
    def toggle(attribute)
      self[attribute] = !send("#{attribute}?")
      self
    end

toggle!(attribute) click to toggle source

Wrapper around `toggle` that saves the record. This method differs from its non-bang version in that it passes through the attribute setter. Saving is not subjected to validation checks. Returns `true` if the record could be saved.

    # File lib/active_record/persistence.rb, line 279
    def toggle!(attribute)
      toggle(attribute).update_attribute(attribute, self[attribute])
    end

touch(name = nil) click to toggle source

Saves the record with the updated_at/on attributes set to the current time. Please note that no validation is performed and no callbacks are executed. If an attribute name is passed, that attribute is updated along with updated_at/on attributes.

    product.touch               # updates updated_at/on
    product.touch(:designed_at) # updates the designed_at attribute and updated_at/on

If used along with `belongs_to` then `touch` will invoke `touch` method on associated object.

    class Brake < ActiveRecord::Base
      belongs_to :car, :touch => true
    end

    class Car < ActiveRecord::Base
      belongs_to :corporation, :touch => true
    end

    # triggers @brake.car.touch and @brake.car.corporation.touch
    @brake.touch

    # File lib/active_record/persistence.rb, line 320
    def touch(name = nil)
      attributes = timestamp_attributes_for_update_in_model
      attributes << name if name

      unless attributes.empty?
        current_time = current_time_from_proper_timezone
        changes = {}

        attributes.each do |column|
          changes[column.to_s] = write_attribute(column.to_s, current_time)
        end

        changes[self.class.locking_column] = increment_lock if locking_enabled?

        @changed_attributes.except!(*changes.keys)
        primary_key = self.class.primary_key
        self.class.unscoped.update_all(changes, { primary_key => self[primary_key] }) == 1
      end
    end

update_attribute(name, value) click to toggle source

Updates a single attribute and saves the record. This is especially useful for boolean flags on existing records. Also note that

- Validation is skipped.

- Callbacks are invoked.

- updated_at/updated_on column is updated if that column is available.

- Updates all the attributes that are dirty in this object.

    # File lib/active_record/persistence.rb, line 177
    def update_attribute(name, value)
      name = name.to_s
      raise ActiveRecordError, "#{name} is marked as readonly" if self.class.readonly_attributes.include?(name)
      send("#{name}=", value)
      save(:validate => false)
    end

update_attributes(attributes, options = {}) click to toggle source

Updates the attributes of the model from the passed-in hash and saves the record, all wrapped in a transaction. If the object is invalid, the saving will fail and false will be returned.

When updating model attributes, mass-assignment security protection is respected. If no `:as` option is supplied then the `:default` role will be used. If you want to bypass the protection given by `attr_protected` and `attr_accessible` then you can do so using the `:without_protection` option.

    # File lib/active_record/persistence.rb, line 212
    def update_attributes(attributes, options = {})
      # The following transaction covers any possible database side-effects of the
      # attributes assignment. For example, setting the IDs of a child collection.
      with_transaction_returning_status do
        self.assign_attributes(attributes, options)
        save
      end
    end

update_attributes!(attributes, options = {}) click to toggle source

Updates its receiver just like `update_attributes` but calls `save!` instead of `save`, so an exception is raised if the record is invalid.

    # File lib/active_record/persistence.rb, line 223
    def update_attributes!(attributes, options = {})
      # The following transaction covers any possible database side-effects of the
      # attributes assignment. For example, setting the IDs of a child collection.
      with_transaction_returning_status do
        self.assign_attributes(attributes, options)
        save!
      end
    end

update_column(name, value) click to toggle source

Updates a single attribute of an object, without calling save.

- Validation is skipped.

- Callbacks are skipped.

- updated_at/updated_on column is not updated if that column is available.

Raises an `ActiveRecordError` when called on new objects, or when the `name` attribute is marked as readonly.

    # File lib/active_record/persistence.rb, line 192
    def update_column(name, value)
      name = name.to_s
      raise ActiveRecordError, "#{name} is marked as readonly" if self.class.readonly_attributes.include?(name)
      raise ActiveRecordError, "can not update on a new record object" unless persisted?

      updated_count = self.class.unscoped.update_all({ name => value }, self.class.primary_key => id)

      raw_write_attribute(name, value)

      updated_count == 1
    end

[Validate]

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