Updated February 27, 2023
Introduction to Rails Generate Models
The following article provides an outline for Rails Generate Models. When it comes to web-based applications, the connections established with the databases in the backend are a critical aspect. The web applications connect with the backend databases using intermediatory controllers or templates. As far as rails are concerned, this template is established using models. So models are class structures that help to template the database structure and sync the template structure with the original database in the backend. This syncing process ensures connecting each database field with the corresponding database items in the backend. There are different ways these models can be created in rails applications, and the predominant technique among them is using generators to create the model structures. There are several generators for creating the models associated with the class.
How do Rails Generate Models Works?
The generating process in rails is a familiar yet non-considerably recommended process in the model creation process. Let us discuss the command structure of the rails generator process briefly, how the process through which the model generation works etc.
Syntax structure:
In the perspective of the rail, the flag g in the rails command is used to denote the generators. The process of creating the generators follows the below syntax,
$rails generator-flag model model_name fieldsHere the first word, rails, mention that the process is related to rails processing. The flag is used to denote the kind of operation intended to be performed. In our case, the operation is generator-based. Hence, this flag becomes “ g “ when we intend to use the generators concept. Next, the keyword model is used to denote the kind of process performed. If we prefer to create a model, the keyword should be the model itself. Then model name should be assigned. This is the important part where the name of the model is declared. The model used further will be running with this name as a reference. Lastly, the fields associated with the models have to be mentioned. This will be the last item in this command. As many fields are used, those many fields have to be declared in the generate model section. All these fields will be driven as representations for the database.
Examples of Rails Generate Models
Below are the different Examples of Rails Generate Models:
Example #1
rails g model bookstore book_id
As far as the above command is concerned, it will generate a model named bookstore. This model will have one field named book_id in it. Since the model has no field type declared, it will be considered a string field model. So the above command will generate one model with the name book store and hold one field called book_id. This is how model creation works in the case of rails concerned.
Example #2
rails g model hospital_details departments, doctor_details,
As far as the above command is concerned, it will generate a model named hospital_Details. This model will have two field-named departments and doctor details in it. Again, since the model does not have any field type declared, the model will be considered a string field model. So like the last example case, the above command will generate one model with the name hospital_details, but in this case, both the fields declared will be string fields. These will remain as string fields as the representation from the database.
Example #3
rails g model student_details roll_numer:integer first_name last_name class_Details:integer
The third example is slightly different from the previous cases; in this case, the model has been declared as a combination of both string and integer fields. Here, integer fields have been declared using a special colon character and assigning the type of field created as the next item. Here this model is associated with four fields. From a business perspective, this model is used for capturing student details. So the model intends to consider all the student details, and in the process, four different details have been considered. First, they are roll_number which will be an integer field, then the firstname will be a character field, and the last name will be a character field again. The last field associated with this model is an integer field, which will be a class details field. So the business level expectation is that the last field will have the standard or grade in which the student will be allotted.
Types of Fields Declared in Rails Generate Models
Different types of fields that can be declared in rails models,
| Field type | Description |
| integer | Used for creating a numerical field value. |
| primary_key | Used for making a field as the primary key for the model. If a key is made as the primary key, then the key will be a unique key associated with the model. |
| decimal | when decimal level values have to be created in the model, then the decimal keyword can be used. |
| float | when floating-point values like 1.5, 6.2, 7.556, etc. have to be generated, then the float key must be used in the model |
| boolean | when a field must have true or false values, then the field must be framed as a boolean-type field. |
| binary | when the field must be associated with only binary values like zeroes and ones, the binary field type must be associated with it. |
| string | Used for holding the string character values. |
| text | Used for holding string character values again, but this field can hold long string values. |
| date | all date-related values can be allocated in this field type. |
| time | all time-related values can be allocated in this field type. |
| datetime | when your values are a combination of date and time, then the DateTime type can be used. |
| timestamp | for holding timestamp values, the timestamp field type can be used. |
Migration file
For every generation generated, there will be a migration file generated in the backend; this generation file will be of the below format; the below-listed migration file will have all the fields associated with the model and other further details related to the project.
class CreatestudentDetails < ActiveRecord::Migration
def change
create_table :student_details do |t|
t.roll_numer
t.first_name
t.last_name
t.class_Details
t.timestamps
end
add_index :student_details, roll_number,first_name,last_name,class_details
end
endConclusion
The article explains the various ways through which the generator function can be performed in the rails models. So the rails models and how they generate commands can be effectively used in the rails generator process. The different files associated with the rails generate function is explained in the above-given article.
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