Here a great video of the creator of Sequel about its internals, it’s definitely worth watching. There are other things, but these are just a subset of the cool things that makes Sequel great and make me love it. For example in an Api that returns Json, with sequel you don’t even need a model class, you just serialize the hashes, no waste here, but with AR it creates a new object for every hash of the results, then you convert them back to Json, a lot of waste in time and memory. Third, its Api, Active record creates a model instance for every record in the query result, those records are huge and in some cases you may not need them. This seems simple, but it’s a killer feature especially in multithreaded environments like Sidekiq. Second, is connections management, while ActiveRecord creates and assigns a connection to each thread and it doesn’t release it until the thread is dead, Sequel just reserves the connection when a query is about to be sent to the db server, once the query is over the connection is returned to the pool. First, performance, sequel is faster than ActiveRecord. Nice article, I know about Sequel and I think it is superior to ActiveRecord in many aspects. sql file : PostgreSQL I have to do a SQL assignment in which I create tables and load data into these tables. Now it's your turn to give this a try & have fun! Using Psequel and Postgres for Hw - how do I create a. You have learned about working with databases in Ruby using an ORM, in this case, the Sequel Ruby gem. If you're using another framework, like Sinatra, then Sequel is a great choice! Summary So I don't think it's worth trying to replace ActiveRecord with Sequel in a Rails app. Well, ActiveRecord is the default ORM for Rails. Now that you've learned how awesome Sequel is, you may be wondering how it compares to ActiveRecord. We can use the same Sequel::Dataset methods.įruit.where(name: "Apple").or(amount: 10).map(:name) Sequel allows you to query the database without a model.Ī Sequel model looks a lot like an ActiveRecord model.Ĭlass Fruit 1, :name=>"Orange", :amount=>10} Let’s get all the entries in the dataset: Now we can add a few records with the insert method. You need a dataset object to interact with a specific table on the database. Now we are ready to start adding data & querying the database! How to Use Sequel Datasets You need to create a table to store data. This creates a Sequel::Database object & assigns it to DB. The first step to start using Sequel is to connect to a database. Let’s discover how to use it! Sequel Example: Connecting to A Database Sequel, named after the vocalization of SQL (a query language for databases), is an ORM. ORM stands for “Object-Relational-Mapping”. If we want to work with the data in an Object-Oriented way, we will need to make the results into objects. Results = client.query("SELECT * FROM users WHERE age > 21") Here’s an example, using raw SQL & the MySQL database.Ĭlient = Mysql2::Client.new(host: "localhost") You can connect to your database in different ways. Sequel is a gem that allows you to access your database, no Rails required.
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