How to execute a raw update sql with dynamic binding in rails

Question

I want to execute one update raw sql like below:

update table set f1=? where f2=? and f3=?

This SQL will be executed by ActiveRecord:

Answer 1

I needed to use raw sql because I failed at getting composite_primary_keys to function with activerecord 2.3.8. So in order to access the sqlserver 2000 table with a composite primary key, raw sql was required.

sql = "update [db].[dbo].[#{Contacts.table_name}] " +
      "set [COLUMN] = 0 " +
      "where [CLIENT_ID] = '#{contact.CLIENT_ID}' and CONTACT_ID = '#{contact.CONTACT_ID}'"
st = ActiveRecord::Base.connection.raw_connection.prepare(sql)
st.execute

If a better solution is available, please share.

Answer 2

Here's a trick I recently worked out for executing raw sql with binds:

binds = SomeRecord.bind(a_string_field: value1, a_date_field: value2) +
        SomeOtherRecord.bind(a_numeric_field: value3)
SomeRecord.connection.exec_query <<~SQL, nil, binds
  SELECT *
  FROM some_records
  JOIN some_other_records ON some_other_records.record_id = some_records.id
  WHERE some_records.a_string_field = $1
    AND some_records.a_date_field < $2
    AND some_other_records.a_numeric_field > $3
SQL

where ApplicationRecord defines this:

# Convenient way of building custom sql binds
def self.bind(column_values)
  column_values.map do |column_name, value|
    [column_for_attribute(column_name), value]
  end
end

and that is similar to how AR binds its own queries.