Is it possible to query on virtual attributes?

rubyonrails-talk
1

I have a Person model with attributes first_name and last_name.

I want to implement autocomplete search that looks that the entire name. Hence I have a method:

def full_name    self.first_name + " " + self.last_name end

Is it possible for me to query on full_name and have rails match the first_name and last_name fields?

I currently receive this error when I try, because full_name isn't an attribute in the database:

SQLite3::SQLException: no such column: full_name: SELECT "people".* FROM "people" WHERE (LOWER(full_name) LIKE 'he %') ORDER BY full_name ASC LIMIT 10

2

Clay H. wrote:

I have a Person model with attributes first_name and last_name.

I want to implement autocomplete search that looks that the entire name. Hence I have a method:

def full_name    self.first_name + " " + self.last_name end

Is it possible for me to query on full_name and have rails match the first_name and last_name fields?

I currently receive this error when I try, because full_name isn't an attribute in the database:

SQLite3::SQLException: no such column: full_name: SELECT "people".* FROM "people" WHERE (LOWER(full_name) LIKE 'he %') ORDER BY full_name ASC LIMIT 10

There's your answer. ActiveRecord find maps directly to database attributes. You could do something like :conditions => ["first_name like ':name%' or last_name like ':name%'", {:name => "Smith"}], or define a computed column in a database view (in which case you will want the rails_sql_views plugin).

Best,

3

In straight SQL you could order on the full name by using SELECT *, CONCAT(first_name, ' ', last_name) AS full_name FROM people ... ORDER BY full_name ASC. See if you can work that into a Rails finder syntax.

Walter