diff options
Diffstat (limited to 'activerecord/lib/active_record/base.rb')
| -rwxr-xr-x | activerecord/lib/active_record/base.rb | 37 |
1 files changed, 28 insertions, 9 deletions
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb index fe528f514c..55befcd29f 100755 --- a/activerecord/lib/active_record/base.rb +++ b/activerecord/lib/active_record/base.rb @@ -365,6 +365,8 @@ module ActiveRecord #:nodoc: # * <tt>:select</tt>: By default, this is * as in SELECT * FROM, but can be changed if you for example want to do a join, but not # include the joined columns. # * <tt>:readonly</tt>: Mark the returned records read-only so they cannot be saved or updated. + # * <tt>:lock</tt>: An SQL fragment like "FOR UPDATE" or "LOCK IN SHARE MODE". + # :lock => true gives connection's default exclusive lock, usually "FOR UPDATE". # # Examples for find by id: # Person.find(1) # returns the object for ID = 1 @@ -384,6 +386,17 @@ module ActiveRecord #:nodoc: # Person.find(:all, :offset => 10, :limit => 10) # Person.find(:all, :include => [ :account, :friends ]) # Person.find(:all, :group => "category") + # + # Example for find with a lock. Imagine two concurrent transactions: + # each will read person.visits == 2, add 1 to it, and save, resulting + # in two saves of person.visits = 3. By locking the row, the second + # transaction has to wait until the first is finished; we get the + # expected person.visits == 4. + # Person.transaction do + # person = Person.find(1, :lock => true) + # person.visits += 1 + # person.save! + # end def find(*args) options = extract_options_from_args!(args) validate_find_options(options) @@ -850,7 +863,7 @@ module ActiveRecord #:nodoc: method_scoping.assert_valid_keys([ :find, :create ]) if f = method_scoping[:find] - f.assert_valid_keys([ :conditions, :joins, :select, :include, :from, :offset, :limit, :order, :readonly ]) + f.assert_valid_keys([ :conditions, :joins, :select, :include, :from, :offset, :limit, :order, :readonly, :lock ]) f[:readonly] = true if !f[:joins].blank? && !f.has_key?(:readonly) end @@ -1028,6 +1041,7 @@ module ActiveRecord #:nodoc: add_order!(sql, options[:order]) add_limit!(sql, options, scope) + add_lock!(sql, options, scope) sql end @@ -1061,14 +1075,19 @@ module ActiveRecord #:nodoc: # The optional scope argument is for the current :find scope. def add_limit!(sql, options, scope = :auto) scope = scope(:find) if :auto == scope - if scope - options[:limit] ||= scope[:limit] - options[:offset] ||= scope[:offset] - end + options = options.reverse_merge(:limit => scope[:limit], :offset => scope[:offset]) if scope connection.add_limit_offset!(sql, options) end # The optional scope argument is for the current :find scope. + # The :lock option has precedence over a scoped :lock. + def add_lock!(sql, options, scope = :auto) + scope = scope(:find) if :auto == :scope + options = options.reverse_merge(:lock => scope[:lock]) if scope + connection.add_lock!(sql, options) + end + + # The optional scope argument is for the current :find scope. def add_joins!(sql, options, scope = :auto) scope = scope(:find) if :auto == scope join = (scope && scope[:joins]) || options[:joins] @@ -1361,12 +1380,12 @@ module ActiveRecord #:nodoc: end VALID_FIND_OPTIONS = [ :conditions, :include, :joins, :limit, :offset, - :order, :select, :readonly, :group, :from ] - + :order, :select, :readonly, :group, :from, :lock ] + def validate_find_options(options) #:nodoc: options.assert_valid_keys(VALID_FIND_OPTIONS) end - + def set_readonly_option!(options) #:nodoc: # Inherit :readonly from finder scope if set. Otherwise, # if :joins is not blank then :readonly defaults to true. @@ -2025,4 +2044,4 @@ module ActiveRecord #:nodoc: value end end -end
\ No newline at end of file +end |