Rails Generate Model With Foreign Key

There are some people who give advice to not use rails generators and create models, controllers and etc. things manually. I don’t agree with them and my advice here is to figure out deeply how they work and then make conclusion.

May 14, 2016  Here, a foreign key of 1 in the categoryid column will relate to food expenses, a foreign key of 2 will relate to accommodation expenses, and so forth. Let's dive in. Generate Models. To start off, I created a new rails application and established the primary database, expenses. Variations on Foreign Key Migrations. Bin/rails generate migration AddPostToComments post:references. Addreference takes a symbol with a table name, and a symbol with the name of a model to add a foreign key for. It'll create a column whose name begins with that model name. If you set the:dependent option to:nullify, then deleting this object will set the foreign key in the association object to NULL. By convention, Rails guesses that the column used to hold the foreign key on the other model is the name of this model with the suffix id added. Railsで、modelにforeignkeyを指定した場合に、orderメソッドを使ってソートしたいです。 下記のようにユーザーと部署テーブルがあり、 ユーザーは部署に2つ所属する場合、 class User foreignkey: 'unitfirstid', class.

In this post I will describe the most often and useful generator - it’s a model generator. I bet if you don’t use rails generators yet this post will make you to change your work. Using Rails generators saves your time, increases performance, helps to get consistent data for your application.

Basic usage

The Rails Command Line. After reading this guide, you will know: How to create a Rails application. How to generate models, controllers, database migrations, and unit tests. How to start a development server. How to experiment with objects through an interactive shell. Rails itself does not know that userid is a foreign key referencing user. In the first command rails generate model Micropost userid:integer it only adds a column userid however rails does not know the use of the col. You need to manually put the line in the Micropost model.

Let’s start with simple example:

This command will generate user model with email field type of string, migration which creates users table, test for model and factory (if you have it). You are able to generate model with few fields like this:

This example will generate yet model with 3 string fields: first_name, last_name and email.

If you want to have model with different type of string pass type after field name following by : and type. Example:

The whole list of available types:

You are able to pass –option parameter to generator. It will inherit generating class from passed name to achieve STI (sing table inheritance):

This example generates model:

Interesting fact that if you generate model in some scope passing model like admin/user or Admin::User:

you will get generated model in scope app/models/admin/user.rb, defined scope app/models/admin.rb which is requred to define module. Let’s see to the content of generated module:

It means that generated table name for Admin::User starts with prefix admin_users. This feature allows to have separated namespaced models as in rails code as in db schema. Very convenient and useful feature for multimodule applications for my opinion.

Advanced usage

Sometimes you have to automatically add index for columns in your migration. It’s not a problem:

Or uniq index:

Set limit for field of integer, string, text and binary fields:

Special syntax to generate decimal field with scale and precision:

Pay attention that you have to wrap parameter price:decimal{10,2} to quotes. It’s vital and you may have incorrect behavior of generator if you don’t do it. Full explanation of this case is here.

You can combine any single curly brace option with the index options:

And the last useful feature of generators - it’s options to generate reference columns (fields which are used in rails as foreign keys):

This command will generate photos table with integer field album_id and also it will add index for this field automatically. Make sure in it by looking at generated migration:

For polymorphic reference use this syntax:

Polymorphic reference with indexes:

Rails Create Model With Foreign Key

Conclusion

As you see there a lot of useful things in rails model generator which can decrease your developing time. Thank you for reading this trolling post but anyway I hope you find it useful because I didn’t find any similar post or literature which describes rails model generator fully.

PS. Foundation for this post was got from this rails description usage which is located only in sources of rails on github.

There are some people who give advice to not use rails generators and create models, controllers and etc. things manually. I don’t agree with them and my advice here is to figure out deeply how they work and then make conclusion.

In this post I will describe the most often and useful generator - it’s a model generator. I bet if you don’t use rails generators yet this post will make you to change your work. Using Rails generators saves your time, increases performance, helps to get consistent data for your application.

Basic usage

Let’s start with simple example:

This command will generate user model with email field type of string, migration which creates users table, test for model and factory (if you have it). You are able to generate model with few fields like this:

This example will generate yet model with 3 string fields: first_name, last_name and email.

If you want to have model with different type of string pass type after field name following by : and type. Example:

The whole list of available types:

You are able to pass –option parameter to generator. It will inherit generating class from passed name to achieve STI (sing table inheritance):

This example generates model:

Interesting fact that if you generate model in some scope passing model like admin/user or Admin::User:

you will get generated model in scope app/models/admin/user.rb, defined scope app/models/admin.rb which is requred to define module. Let’s see to the content of generated module:

It means that generated table name for Admin::User starts with prefix admin_users. This feature allows to have separated namespaced models as in rails code as in db schema. Very convenient and useful feature for multimodule applications for my opinion.

Advanced usage

Sometimes you have to automatically add index for columns in your migration. It’s not a problem:

Or uniq index:

Set limit for field of integer, string, text and binary fields:

Special syntax to generate decimal field with scale and precision:

Pay attention that you have to wrap parameter price:decimal{10,2} to quotes. It’s vital and you may have incorrect behavior of generator if you don’t do it. Full explanation of this case is here.

You can combine any single curly brace option with the index options:

And the last useful feature of generators - it’s options to generate reference columns (fields which are used in rails as foreign keys):

This command will generate photos table with integer field album_id and also it will add index for this field automatically. Make sure in it by looking at generated migration:

For polymorphic reference use this syntax:

Polymorphic reference with indexes:

Conclusion

As you see there a lot of useful things in rails model generator which can decrease your developing time. Thank you for reading this trolling post but anyway I hope you find it useful because I didn’t find any similar post or literature which describes rails model generator fully.

Rails G Model Foreign Key

Microsoft office 2010 home and business activation key generator. PS. Foundation for this post was got from this rails description usage which is located only in sources of rails on github.