What is the difference between delete and destroy in Rails?
Basically destroy runs any callbacks on the model while delete doesn’t. Deletes the record in the database and freezes this instance to reflect that no changes should be made (since they can’t be persisted). Returns the frozen instance.
What does ActiveRecord base do?
ActiveRecord::Base indicates that the ActiveRecord class or module has a static inner class called Base that you’re extending.
What does ActiveRecord destroy return?
Method: ActiveRecord::Relation#destroy_all Returns the collection of objects that were destroyed; each will be frozen, to reflect that no changes should be made (since they can’t be persisted).
Does ActiveRecord cache?
ActiveRecord makes accessing your database easy, but it can also help make it faster by its intelligent use of caching.
What does rake db seed do?
When you run rake db:seed it will load all the admin data into your application. Rails seeding is generally for development and/or staging environments, there are only a few uses in production.
What does rake db drop do?
An added nuance is that rake db:reset loads directly from your schema. rb file as opposed to running all the migrations files again. You data gets blown away in all cases.
What is an Active Record object?
In Active Record, objects carry both persistent data and behavior which operates on that data. Active Record takes the opinion that ensuring data access logic as part of the object will educate users of that object on how to write to and read from the database.
Can you use Active Record without Rails?
One of the primary aspects of ActiveRecord is that there is very little to no configuration needed. It follow convention over configuration. ActiveRecord is commonly used with the Ruby-on-Rails framework but you can use it with Sinatra or without any web framework if desired.
What is Russian doll caching?
Ruby on Rails Caching Russian Doll Caching You may want to nest cached fragments inside other cached fragments. This is called Russian doll caching . The advantage of Russian doll caching is that if a single product is updated, all the other inner fragments can be reused when regenerating the outer fragment.
What is Seeds RB?
The seeds.rb file is where the seed data is stored, but you need to run the appropriate rake task to actually use the seed data. Using rake -T in your project directory shows information about following tasks: rake db:seed. Load the seed data from db/seeds.rb.
How do I clear a db seed?
You can delete everything and recreate database + seeds with both:
- rake db:reset : loads from schema. rb.
- rake db:drop db:create db:migrate db:seed : loads from migrations.
What is the difference between destroy () and delete () in ActiveRecord?
If the before_destroy callback return false the action is cancelled and destroy returns false. See ActiveRecord::Callbacks for further details. delete will only delete current object record from db but not its associated children records from db. destroy will delete current object record from db and also its associated children record from db.
How does the delete method in ActiveRecord work?
This is what ActiveRecord does when calling the delete method: In basic terms, using delete removes the row i n the database using a primary key matching the id argument, using a SQL DELETE statement, and returns the number of rows deleted. You can delete multiple rows at once by passing an Array of ids. But when calling delete, that’s it.
How do I delete a row in ActiveRecord?
This is what ActiveRecord does when calling the delete method: In basic terms, using delete removes the row i n the database using a primary key matching the id argument, using a SQL DELETE statement, and returns the number of rows deleted. You can delete multiple rows at once by passing an Array of ids.
Should I use destroy or Not Destroy Records in a database?
However, if you care about models callbacks, referential integrity, or validations (for example, setting a criteria to not destroy a record unless a certain condition is “true”), then use destroy. In addition, there is always debate within the coding community (or at least that one guy on Stack Overflow that thinks you’re wrong).