What does Rails DB Reset do?

When working on a Rails app, you might sometimes need to drop the local database and start fresh with data loaded from db/seeds. rb, what do you do? Short answer: use rake db:reset . This drops the database, then loads the schema with rake db:schema:load and then seeds the data with rake db:seed .

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Regarding this, what does DB Reset do?

Difference between rake db:migrate db:reset and db:schema:load. rake db:migrate - Runs the migrations which haven't been run yet. rake db:reset - Clears the database (presumably does a rake db:drop + rake db:create + rake db:migrate ) and runs migration on a fresh database.

Also, how do I delete a database in Rails? When working on a Rails app, you might sometimes need to drop the local database and start fresh with data loaded from db/seeds. rb, what do you do? Short answer: use rake db:reset . This drops the database, then loads the schema with rake db:schema:load and then seeds the data with rake db:seed .

One may also ask, what does Rails DB setup do?

4.2 Setup the Database The rails db:setup command will create the database, load the schema, and initialize it with the seed data.

How does Rails know which migrations to run?

1 Answer. Rails creates a table in your database called schema_migrations to keep track of which migrations have run. The table contains a single column, version . When Rails runs a migration, it takes the leading digits in the migration's file name and inserts a row for that "version", indicating it has been run.

23 Related Question Answers Found

What is DB Migrate?

Database migration — in the context of enterprise applications — means moving your data from one platform to another. There are many reasons you might want to move to a different platform. For example, a company might decide to save money by moving to a cloud-based database.

How does Rails migration work?

A Rails migration is a tool for changing an application's database schema. Instead of managing SQL scripts, you define database changes in a domain-specific language (DSL). The code is database-independent, so you can easily move your app to a new platform.

How do I run a specific migration in Rails?

To run a specific migration up or down, use db:migrate:up or db:migrate:down . The version number in the above commands is the numeric prefix in the migration's filename. For example, to migrate to the migration 20160515085959_add_name_to_users. rb , you would use 20160515085959 as the version number.

What does rake db seed do?

rake db:seeds loads the data from db/seeds. rb into the database. This is generally used for development and production databases. It's permanent data that you use to start an empty application.

How do you drop migration in Rails?

Run below commands from app's home directory:

rake db:migrate:down VERSION="20140311142212" (here version is the timestamp prepended by rails when migration was created.
Run "rails destroy migration migration_name" (migration_name is the one use chose while creating migration.

What is structure SQL?

structure. sql instead is a SQL representation of the database and it depends on the specific database you selected. You only use the structure if you have specific database features that you need and that can't be represented by the schema.

What is bundle exec rails?

bundle exec is a Bundler command to execute a script in the context of the current bundle (the one from your directory's Gemfile). rake db:migrate is the script where db is the namespace and migrate is the task name defined.

How do I start rails console?

Go to your browser and open http://localhost:3000, you will see a basic Rails app running. You can also use the alias "s" to start the server: rails s . The server can be run on a different port using the -p option. The default development environment can be changed using -e .

What is migration in Ruby on Rails?

Ruby on Rails - Migrations. Advertisements. Rails Migration allows you to use Ruby to define changes to your database schema, making it possible to use a version control system to keep things synchronized with the actual code.

What does schema mean?

Database schema. The term "schema" refers to the organization of data as a blueprint of how the database is constructed (divided into database tables in the case of relational databases). The formal definition of a database schema is a set of formulas (sentences) called integrity constraints imposed on a database.

What are active records?

Active records are documents which are still actively being used by an office. They are usually referenced on a daily or monthly basis. Often times, if in paper, these records will be located in a handy place within the office since they are used frequently.

What is rake task?

Rake is a software task management and build automation tool. Rake uses Ruby's anonymous function blocks to define various tasks, allowing the use of Ruby syntax. It has a library of common tasks: for example, functions to do common file-manipulation tasks and a library to remove compiled files (the "clean" task).

How do I rollback a particular migration in laravel?

Change the batch number of the migration you want to rollback to the highest. Run migrate:rollback.

Go to DB and delete/rename the migration entry for your-specific-migration.
Drop the table created by your-specific-migration.
Run php artisan migrate --path=/database/migrations/your-specific-migration. php.

How do I create a migration file in rails?

The way of creating model by using the rails generates command in rails command prompt. Put the following rails code. The model file is located in db directory, inside migrate folder.

Create two methods using the following code,

class CreateUsers < ActiveRecord::Migration[5.1]
def up.
end.
def down.
end.
end.

What does rake do in Ruby?

Rake is a tool you can use with Ruby projects. It allows you to use ruby code to define "tasks" that can be run in the command line. Rake can be downloaded and included in ruby projects as a ruby gem. Once installed, you define tasks in a file named "Rakefile" that you add to your project.

How do I delete a migration?

Here's what you can do.

Look at your migrations table and find the migration you deleted.
create a new migration with the name of the deleted migration (add the timestamps from the migrations table.
run php artisan migrate:rollback.
delete the migration and continue.

How do I delete a Postgres database?

Introduction to PostgreSQL DROP DATABASE statement

To delete a database: Specify the name of the database that you want to delete after the DROP DATABASE clause. Use IF EXISTS to prevent an error from removing a non-existent database. PostgreSQL will issue a notice instead.