Is there a way to convert a Rails model into an insert query?
For instance, if I have a model like:
m = Model.new
m.url = "url"
m.header = "header"
How can I get the corresponding SQL query ActiveRecord would generate if I did m.save?
I want to get: "INSERT INTO models(url, header) VALUES('url', 'header')" if possible.
Note: I don't want to actually save the model and get the query back (from log file, etc). I want to get the query IF I chose to save it.
On Rails 4.1, I found the below code snippet working:
record = Post.new(:title => 'Yay', :body => 'This is some insert SQL')
record.class.arel_table.create_insert
.tap { |im| im.insert(record.send(
:arel_attributes_with_values_for_create,
record.attribute_names)) }
.to_sql
Thanks to https://coderwall.com/p/obrxhq/how-to-generate-activerecord-insert-sql
Tested in Rails 3.2.13: I think I got it right this time, it definitely does not persist to the db this time. It also won't fire validations or callbacks so anything they change won't be in the results unless you've called them some other way.
Save this in lib as insert_sqlable.rb and you can then
#in your models or you can send it to ActiveRecord::Base
include InsertSqlable
Then it is model.insert_sql to see it.
#lib/insert_sqlable
module InsertSqlable
def insert_sql
values = arel_attributes_values
primary_key_value = nil
if self.class.primary_key && Hash === values
primary_key_value = values[values.keys.find { |k|
k.name == self.class.primary_key
}]
if !primary_key_value && connection.prefetch_primary_key?(self.class.table_name)
primary_key_value = connection.next_sequence_value(self.class.sequence_name)
values[self.class.arel_table[self.class.primary_key]] = primary_key_value
end
end
im = self.class.arel_table.create_insert
im.into self.class.arel_table
conn = self.class.connection
substitutes = values.sort_by { |arel_attr,_| arel_attr.name }
binds = substitutes.map do |arel_attr, value|
[self.class.columns_hash[arel_attr.name], value]
end
substitutes.each_with_index do |tuple, i|
tuple[1] = conn.substitute_at(binds[i][0], i)
end
if values.empty? # empty insert
im.values = Arel.sql(self.class.connectionconnection.empty_insert_statement_value)
else
im.insert substitutes
end
conn.to_sql(im,binds)
end
end
It turns out the code is in ActiveRecord::Relation and not ActiveRecord::Persistence. The only significant change is the last line which generates the sql instead of performing it.
If you dont want to save the model you call m.destroy when you are done with the object.
You can log the sql query by debugging it like this
Rails.logger.debug "INSERT INTO models(url, header) VALUES(#{m.url}, #{m.header}).inspect
After search a lot over the Internet and forums, I think I found a better solution for your problem: just requires two line of code.
I found a good gem that do exactly what you want, but this gem only works for Rails 3.2 and older. I talked with author and he doesn't want support this gem anymore. So I discovered by myself how to support Rails 4.0 and now I'm maintaining this gem.
For objects:
object.to_sql_insert
# INSERT INTO modelName (field1, field2) VALUES ('Wow, amaze gem', 'much doge')
For array of objets:
array_of_objects.to_sql_insert
# INSERT INTO modelName (field1, field2) VALUES ('Awesome doge', "im fucking cop")
# INSERT INTO modelName (field1, field2) VALUES ('much profit', 'much doge')
# (...)
Just see the Github of this project and you'll find how to install and use this wonderful gem.
Model.news inside a transaction later?