Rails update attributes without save

Question

Is there an alternative to update attributes that does not save the record   So I could do something like    car   Car new  make   gt   GMC    other processing  car update attributes  model   gt   Sierra    year   gt   2012    looks   gt   Super Sexy  wanna make love to it    other processing  car save   BTW  I know I can  car model    Sierra   but I want to update them all on one line

User · Accepted Answer

I believe what you are looking for is assign attributes   It s basically the same as update attributes but it doesn t save the record   class User  lt  ActiveRecord  Base   attr accessible  name   attr accessible  name   is admin   as   gt   admin end  user   User new user assign attributes    name   gt   Josh    is admin   gt  true      Raises an ActiveModel  MassAssignmentSecurity  Error user assign attributes    name   gt   Bob    user name            gt   Bob  user is admin        gt  false user new record      gt  true

User · Answer

You can use the  attributes  method    car attributes     model   gt   Sierra    years   gt   1990    looks   gt   Sexy     Source  http   api rubyonrails org classes ActiveRecord Base html  attributes  new attributes  guard protected attributes   true  Allows you to set all the attributes at once by passing in a hash with keys matching the attribute names  which again matches the column names    If guard protected attributes is true  the default   then sensitive attributes can be protected from this form of mass-assignment by using the attr protected macro  Or you can alternatively specify which attributes can be accessed with the attr accessible macro  Then all the attributes not included in that won   t be allowed to be mass-assigned   class User  lt  ActiveRecord  Base   attr protected  is admin end  user   User new user attributes      username   gt   Phusion    is admin   gt  true   user username       gt   Phusion  user is admin       gt  false  user send  attributes      username   gt   Phusion    is admin   gt  true    false  user is admin       gt  true

User · Answer

For mass assignment of values to an ActiveRecord model without saving  use either the assign attributes or attributes  methods   These methods are available in Rails 3 and newer   However  there are minor differences and version-related gotchas to be aware of   Both methods follow this usage    user assign attributes  model   Sierra   year   2012   looks   Sexy      user attributes     model   Sierra   year   2012   looks   Sexy      Note that neither method will perform validations or execute callbacks  callbacks and validation will happen when save is called   Rails 3  attributes  differs slightly from assign attributes in Rails 3   attributes  will check that the argument passed to it is a Hash  and returns immediately if it is not  assign attributes has no such Hash check   See the ActiveRecord Attribute Assignment API documentation for attributes    The following invalid code will silently fail by simply returning without setting the attributes    user attributes       model   Sierra       year   2012       looks   Sexy        attributes  will silently behave as though the assignments were made successfully  when really  they were not   This invalid code will raise an exception when assign attributes tries to stringify the hash keys of the enclosing array    user assign attributes     model   Sierra       year   2012       looks   Sexy         assign attributes will raise a NoMethodError exception for stringify keys  indicating that the first argument is not a Hash   The exception itself is not very informative about the actual cause  but the fact that an exception does occur is very important   The only difference between these cases is the method used for mass assignment  attributes  silently succeeds  and assign attributes raises an exception to inform that an error has occurred   These examples may seem contrived  and they are to a degree  but this type of error can easily occur when converting data from an API  or even just using a series of data transformation and forgetting to Hash   the results of the final  map   Maintain some code 50 lines above and 3 functions removed from your attribute assignment  and you ve got a recipe for failure   The lesson with Rails 3 is this  always use assign attributes instead of attributes    Rails 4  In Rails 4  attributes  is simply an alias to assign attributes   See the ActiveRecord Attribute Assignment API documentation for attributes    With Rails 4  either method may be used interchangeably   Failure to pass a Hash as the first argument will result in a very helpful exception  ArgumentError  When assigning attributes  you must pass a hash as an argument   Validations  If you re pre-flighting assignments in preparation to a save  you might be interested in validating before save  as well   You can use the valid  and invalid  methods for this   Both return boolean values   valid  returns true if the unsaved model passes all validations or false if it does not   invalid  is simply the inverse of valid   valid  can be used like this    user assign attributes  model   Sierra   year   2012   looks   Sexy    valid    This will give you the ability to handle any validations issues in advance of calling save

User · Answer

You can use assign attributes or attributes   they re the same   Update methods cheat sheet  for Rails 6      update   assign attributes   save   attributes    alias of assign attributes update attributes   deprecated  alias of update      Source  https   github com rails rails blob master activerecord lib active record persistence rb https   github com rails rails blob master activerecord lib active record attribute assignment rb  Another cheat sheet  http   www davidverhasselt com set-attributes-in-activerecord  cheat-sheet

[ruby-on-rails] Rails update_attributes without save?

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