在Rails（PostgreSQL）中批量更新单个记录

Question

I have stumble on a problem to update a set of records.

In Database I have

id | name   | info::hstore | friends[]::varchar 
1  | Claire | {}           | []
2  | Mary   | {}           | []
3  | Bob    | {}           | []

I have for an example an array of hashes:

[ 
  {id: 1, name: "Claire", info: {age: 21, sex: 'f'}, friends: ['Mary', 'Bob']}, 
  {id: 2, name: "Mary", info: {age: 16, sex: 'f'}, friends: ['Mike']},
  {id: 3, name: "Bob", info: {age: 28, sex: 'm'}, friends: ['James']}
]

All records are already in DB, I want only to UPDATE the existent with columns from hashes, the hashes all have same number of fields to update: name, info and friends.

There is a gem active-record-import but it does only inserts. Also the method #update_all does not work as I have individual data to update each record depending on id. Don't want to make a raw SQL insert as my rows have Postgres hstore and array types, don't want to make lot of data manipulations.

There could be about 10,000 - 100,000 records to update.

Env: Postgres 9.4, Rails 3 (also if there is a good solution in Rails4 would appreciate to hear about)

Answer 1

So I am not sure if you are against this method from what you've said so far but you could do:

update_info = [{id: 1, name: "Claire", info: {age: 21, sex: 'f'}, friends: ['Mary', 'Bob']}, 
               {id: 2, name: "Mary", info: {age: 16, sex: 'f'}, friends: ['Mike']},
               {id: 3, name: "Bob", info: {age: 28, sex: 'm'}, friends: ['James']}
                   ]

update_info.each do |row|
  user = User.find(row[:id])
  user.update(info: row[:info], friends: row[:friends])
end

that is about the only way to get your info from an array of hashes into the DB. With Postgres you can do a mass update from another table with something that is similar to a join. But if you are going to go to all that trouble, then you should just do this on the DB console psql or with a GUI DB program that lets you do SQL queries. Some things are just better done in the DB because that is what it's designed to do.