Non persistent ActiveRecord model attributes
Of course use good old ruby’s attr_accessor. In your model: attr_accessor :foo, :bar You’ll be able to do: object.foo = ‘baz’ object.foo #=> ‘baz’
activerecord
Log the actual SQL query using ActiveRecord with Yii2?
Method 1 With relations that return yii\db\ActiveQuery instance it’s possible to extract the raw SQL query directly in code for example with var_dump(). For example if we have user relation: /** * @return \yii\db\ActiveQuery */ public function getUser() { return $this->hasOne(User::className(), [‘id’ => ‘user_id’]); } You can then var_dump() the raw SQL like that: var_dump($model->getUser()->prepare(Yii::$app->db->queryBuilder)->createCommand()->rawSql); … Read more
has_and_belongs_to_many, avoiding dupes in the join table
Prevent duplicates in the view only (Lazy solution) The following does not prevent writing duplicate relationships to the database, it only ensures find methods ignore duplicates. In Rails 5: has_and_belongs_to_many :tags, -> { distinct } Note: Relation#uniq was depreciated in Rails 5 (commit) In Rails 4 has_and_belongs_to_many :tags, -> { uniq } Prevent duplicate data … Read more
Is there a way to avoid automatically updating Rails timestamp fields?
Do this in a migration or in a rake task (or in the new database seeds if you’re on edge rails): ActiveRecord::Base.record_timestamps = false begin run_the_code_that_imports_the_data ensure ActiveRecord::Base.record_timestamps = true # don’t forget to enable it again! end You can safely set created_at and updated_at manually, Rails won’t complain. Note: This also works on individual … Read more
ActiveRecord find_each combined with limit and order
The documentation says that find_each and find_in_batches don’t retain sort order and limit because: Sorting ASC on the PK is used to make the batch ordering work. Limit is used to control the batch sizes. You could write your own version of this function like @rorra did. But you can get into trouble when mutating … Read more
How to list of all the tables defined for the database when using active record?
Call ActiveRecord::ConnectionAdapters::SchemaStatements#tables. This method is undocumented in the MySQL adapter, but is documented in the PostgreSQL adapter. SQLite/SQLite3 also has the method implemented, but undocumented. >> ActiveRecord::Base.connection.tables => [“accounts”, “assets”, …] See activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb:21, as well as the implementations here: activerecord/lib/active_record/connection_adapters/mysql_adapter.rb:412 activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb:615 activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb:176
How to show SQL queries run in the Rails console?
Rails 3+ Enter this line in the console: ActiveRecord::Base.logger = Logger.new(STDOUT) Rails 2 Enter this line in the console: ActiveRecord::Base.connection.instance_variable_set :@logger, Logger.new(STDOUT)
PGError: ERROR: aggregates not allowed in WHERE clause on a AR query of an object and its has_many objects
The error message tells you: aggregates not allowed in WHERE clause count() is an aggregate function. Use the HAVING clause for that. The query could look like this: SELECT r.* FROM recommendations r JOIN approvals a ON a.recommendation_id = r.id WHERE r.user_id = $current_user_id GROUP BY r.id HAVING count(a.recommendation_id) = 1 With PostgreSQL 9.1 or … Read more
Store the day of the week and time?
Is there a way for me to store the the record for Tuesday and Wednesday in one row or do should I have two records? There are several ways to store multiple time ranges in a single row. @bma already provided a couple of them. That might be useful to save disk space with very … Read more
Rails 3.1 limit user created objects
Try something like this: class User < ActiveRecord::Base has_many :things end class Things <ActiveRecord::Base belongs_to :user validate :thing_count_within_limit, :on => :create def thing_count_within_limit if self.user.things(:reload).count >= 5 errors.add(:base, “Exceeded thing limit”) end end end Edit: updated for Rails 3