Loop through hash and find records to delete in Ruby

Question

I am self-learning ruby by watching few videos and reading through blogs. I am currently in a situation where I have to parse the below parameters that I receive from an external CRM system into RUBY and find the relevant records from the database and delete them. It works well when I get a single record through below code:

temp_id = params[:salesforce_id]
Table.find_or_initialize_by(:id => temp_id).destroy

but I am struggling when I have to parse through multiple records like below, I get this error "ArgumentError (wrong number of arguments (given 0, expected 1)):" I might have to loop through this but any sample code will really help.

{"_json"=>[{"id"=>"1"}, {"id"=>"2"}, {"id"=>"3"}], "delete_record"=>{"_json"=>[{"id"=>"1"}, {"id"=>"2"}, {"id"=>"3"}]}}

Thanks

Answer 1

The structure you have is a Hash (A) having a key "_json" and a key "delete_record" corresponding to a Hash (B) value. This Hash contains a key/value pair with "_json" as the key, and an Array as the value. This Array contains (several) Hash (C) objects.

What you want here is:

1. Get the value inside Hash (A) for key "delete_record", which is Hash (B)
2. Get the value inside Hash (B) for key "_json", which is an Array of Hash objects (C)
3. For each Hash (C) inside the Array, get the value for the key "id".

You can do the following:

data = {
  "_json"=>
    [{"id"=>"1"}, {"id"=>"2"}, {"id"=>"3"}], 
  "delete_record"=>
    {"_json"=>[{"id"=>"1"}, {"id"=>"2"}, {"id"=>"3"}]}
}
# step 1
data_for_delete_record_key = data['delete_record']
# step 2
array_of_hashes_with_id_key = data_for_delete_record_key['_json']
# step 3
ids_to_destroy = array_of_hashes_with_id_key.map { |hash| hash['id'] }

Then, you can simply use the following to destroy the matching records:

Table.where(id: ids_to_destroy).destroy_all