I'm using bcrypt for Rails API authentication - This is ofc after many hours of trying to figure out how to get Devise to work via Rails api to no avail. (trying to do API only with React frontend).
Anyways, I made it until technical debt had to be paid. BCrypt password_digest and Devise Hashed_password are at a stalemate and I can't seem to get one to ignore the other. I need to change that portion of the schema to accommodate for bcrypt. What's the best way to go about this?
Doing database transformations without using migrations is as easy as running rails db which will start the CLI for your database and typing the SQL. But then you have to repeat those steps across the test/development/production databases and make sure any other developers working on the project also perform those steps on their local databases.
This is a really error prone process and actually solving the problem with migrations is probably a lot less insurmountable than you think.
What's the best way to go about this?
The best solution to ignorance is knowledge.
ActiveRecord migrations are just a Domain Specific Language (DSL) to create SQL queries and a mechanism to run migrations against different databases and keep tabs on which migrations have been run through a metadata table in the database.
Even if you can't express whatever query you are trying to perform through the DSL you can still use any arbitrary SQL string.
Related
I'm a bit of a Rails beginner, so I'm sorry if this question is easy. I'm wondering how I am supposed to modify the Rails database as a developer without letting users of the site modify data.
More information:
Let's say I am trying to create a website that lists books along with their information. I want users to be able to see these books, but not add/delete them. As a developer, I want a way to add books without using the command line (hard to edit mistakes). What's the easiest way for me to do this? Would there be any differences between the development database and a live hosted one?
I think there are a few approaches to do this.
different user roles. This technically breaks the rule of without letting users of the site modify data, but being able to differentiate between normal and admin users means you can limit who actually can add data into the database. I used cancancan as a way to authorize requests but I know there are others.
I agree doing it using the command line isn't ideal, but rails do support rake tasks. You can create a task that will handle most of the logic and all you need to do is something like
rake create_book["name here"]
This will make the process less error-prone.
Create data using rails migrations. Rails can generate the skeleton file for you, and you just ran any ActiveRecord methods. However, the main purpose of migration is to update the database schema, but they can seed the database as well. here's the example from the dcos
Would there be any differences between the development database and a live-hosted one?
Yea, they should be totally separate database instances. You don't want to have your development database be the same as the live one. This would cause major problems. Rails have a concept of environments where you can use different configurations, so you can pick and choose what database URL to use.
like #davidhu said here The best approach really is the use of authorization. If only admin can see a page to CRUD the books then you don't have to worry about normal users doing same plus it makes it easy for you as the admin to make changes or add to the collection. Add the gem (or reinvent the wheel) then Rails will take care of the rest for you.
My database admins do not want to control access to any drop/alter/create commands. Is there anyway to emulate what rails is doing to the schema migrations table and convert the migrations themselves in a reliable way to fake rails out into thinking it has been ran and also handle rollbacks? They want to run this from their end of course. I have seen a few suggestions, but no wholistic approach. Perhaps the answer is it really shouldn't be done, which is what I think right now as I believe it will just cause headaches and unreliability down the road.
Perhaps a stupid question, and without code, so I'm not sure I'm on the right StackExchange site. If so, sorry and give me a comment please.
I begin programming in Sinatra (only intranet until now) and in the samples they almost always use migration with activerecord, the same with RoR.
I have experience enough with activerecord itself and it is very helpfull but I'm not sure why migration is always used ? If I create a project I just create a SQL script or a Ruby activerecord script that does the creation of the DB for me and that's it..
If I need the site or script somewhere else I just need to execute that script and ready.
Obviously I'm missing here a lot, so who can me explain the other benefits or point me to a good explanation ?
From Rails docs:
Migrations are a convenient way to alter your database schema over
time in a consistent and easy way. They use a Ruby DSL so that you
don't have to write SQL by hand, allowing your schema and changes to
be database independent.
So, the main two benefits are:
It's like Git for db schema, you won't know how that's useful until you are in a mid-size or big project with many contributors and someone makes a bobo :)
You write ruby code to build your db schema, this way if you decide to move from mysql to pg for example, you don't need to open up pg manual and check code compatibility
Update
In the api docs of migrations, you will find many nice use cases (to be honest i didn't know about half of them) ... check it out (http://api.rubyonrails.org/classes/ActiveRecord/Migration.html)
Building a creation script for your database is great, provided two things:
All your database deployments are on new machines
You get your database schema exactly right the first time
In our modern agile environment we not only don't believe it is possible for a project larger than a few lines of code, we also don't encourage aspiring to it.
Active Record's Migrations offer a way to describe your database incrementally. Each "migration" defines how to add its features to the database ("upgrade"), and how to remove them if necessary ("downgrade").
When running migrations, on top of actually running the scripts, Active Record also maintains its own table (schema_migrations), to remember which migrations have been applied to the database, and which are pending.
This enables you to build your database alongside the features as you develop them. It also facilitates working in teams, since each team member develops her own migrations, and Active Record "stitches" everything together, so you don't have to maintain a monolithic creation script.
I'm a PHP programmer for over a decade and making the move to RoR. Here is what I'm used to from the PHP world:
Create DB schema in a tool like MySQL WorkBench -- and make fields precisely the size I want without wasting space (e.g. varchar(15) if it's ip_address).
Write models using Datamapper and place those exact field lengths and specifications in there so my app doesn't try to put in any larger values.
In the RoR world from what I've seen over the past two days, this seems to be the flow suggested:
Add fields / schema using the command line which creates a migration script and apparently created large ass fields (e.g. "ip_address string" is probably making the field varchar(255) in the db when I run the migration).
Put in validations during model creation.
Am I missing something here? What's the process in the RoR world for enterprise level applications where you actually want to create a highly customized schema? Do I manually write out migration scripts?
The scaffolding is what you use to get started quickly. But before running the migration, you can edit it and add constraints and specific column lengths.
Validations specified in the model (in the ruby code) does not carry the same level of security as validations /constraints specified on the database. So you still need to define those on the database.
While it is possible to work with Rails without migrations, I would strongly advice against it. In some cases it cannot be avoided (when working with legacy databases for instance).
The biggest advantage of using the migrations is that your database schema, accross different platforms, can be held in sync through different stages. E.g. your development and your production database. When deploying your code, the migrations will take care that the database is migrated correctly.
You can edit the migration scripts before you run the migration in order to customize the fields.
Yes, if you need to tweak the defaults, you edit the migration scripts.
Also note that you don't need to use migrations, they're a "convenience" while iterating through DB development. There's nothing that says you must use them. The active record pattern doesn't rely on how the DB tables/fields/etc. are created or defined.
For example, migrations are useless when dealing with legacy DBs, but you can still write a Rails app around them.
I'm switching to RoR from ASP.NET MVC. Yeah, migrations are cool, but I do not need to use different databases in my web applications. Postgresql will do just fine.
So is it okay if I use PGAdmin to create and administer my databases and schema and avoid all these fancy migrate, rake etc?
Update
Thanks everyone! Now I better understand what migrations are, and why I should use them.
I don't think that's what migration means.
Migrations in rails (and in other frameworks) is a method by which you can use to update your database schema when there are multiple versions of the same database running
For example, you may have two databases, one running on your production server, and another running locally for development. After a few days of coding, your local development database may looks a bit different. With migrations, you can simply push your code to the production server and then run the migrations to automatically update your production database so it is up-to-date with the one you use locally for development.
So, to answer your question, Yes it is OK but you might not get a few of the migrations niceties when the time comes that you'll have to maintain multiple versions of your database.
Have to agree with charkit but one (rather two) important note why you should use migrations: Migrations don't make up the model definitions. They are stored seperately in a file schema.rb. This defines the rows and tables of your database. When looking into the file, you find these lines:
This file is auto-generated from the current state of the database. Instead of editing this file, please use the migrations feature of Active Record to incrementally modify your database, and then regenerate this schema definition.
The second reason is for testing: you can easily set up a test database to run all your tests against without the need to touch the "real" database. I know when developing, this is not a big problem but this will get more important after some time.
So, yes, it is possible to use PGAdmin to create all your database related stuff but you should not forget to always keep the schema file up to date and come up with a solution for testing.
With migrations you're able to develop your database schema in Ruby and this is usually database indpendent.
In short, spend the 20 minutes or so to really get migrations and the value they add. Then determine whether or not you want to ditch them. Strangely for me I learned Rails before I started my first MVC project; one of the things I missed most was migrations.
From a technical standpoint you should be fine without them.