#Elixir ecto how to
#Elixir ecto full
#Elixir ecto series
#Elixir ecto free

It relies on simple data structures such as maps to carry all needed information and metadata.

#Elixir ecto free

NET has its Entity Framework, and Ruby has ActiveRecord.Įlixir's different because it's free from OOP's heavy, bloated objects that always carry a lot of internal state information. In object-oriented languages object-relational mapping libraries dealt with managing database connection, constructing queries and mapping the results to _objects_.

Durability - the database must be crash-resilient, which means all data committed before a crash must still be seen as committed after the system is up again.

#Elixir ecto full

Read up if you're interested in the full story).

(Though actually, that's a simplification. Isolation - core to how databases handle concurrency, transaction A's intermediate steps should not be visible to other transactions before transaction A is committed.This is related to atomicity, because any transaction abort must transition the database to a previously consistent all integrity constraints must always be met. The database must be consistent at all times, i.e. When any step fails or the application decides so, the database will be rolled back to the state before transaction started. A transaction being atomic means that each of its steps is inseparable from the others. What does it mean in technical terms? It means that our database is ACID. This slightly scary term is just an acronym for: Atomicity, Consistency, Isolation & Durability. On top of that, we obviously want all of this to hold true even when our system crashes. We require that it not be possible to transfer $100 from A when its balance is only $50 (surprise, eh?). Since our systems are capable of handling multiple operations concurrently, we don't want any agent to read either account's balance before the transfer is completed. It is mandatory that both operations are performed inseparably, because no money can be lost.

Otherwise, let's delve a bit deeper into the mechanisms of database services.Ĭonsider a bank transfer, consisting of subtracting money from account A and then adding to B. If you're familiar with SQL databases, feel free to skip this section. However obscure it might sound, the combination of Elixir's functional character and other traits make it so easy to translate business requirements to algorithms powering excellent apps - and, with this guide, we're going to show you part of the reason why. Finally, we'll get to explain how it feels superior to different ORMs.

#Elixir ecto how to

Then, we'll outline how to approach them in Elixir, using 'the Ecto way'.

We'll explain what the purpose and characteristics of transactions are.

When no prefix is set, Postgres queries are assumed to be executed in the public schema, while MySQL queries are assumed to be executed in the database set in the config for the repo.įor example, if we want to insert a new element in our database with Repo.This is a thorough guide for SQL experts and newbies alike, so let's summarize what we'll talk about in this article: According to the documentation, for Postgres users, prefix will specify the schema where the table is located, while for MySQL users will specify the database where the table is located.

#Elixir ecto series

Most of the methods provided by Ecto which directly interacts with the database have a series of options, in which the most important one for multi-tenancy is prefix. Some time ago I had to tackle the migration of an application with a regular database to a multi-tenancy one, and I would like to share my experience here.ĭespite the existence of libraries like apartmentex, triplex or tenantex, I wanted to make the migration as dependency free as possible, so I made my own management for the multi-tenancy.