Extra form elements and SQLFORM without database IO in web2py

SQLFORM without database IO

Sometimes we want to utilise SQLFORM to generate a form from a database table and validate a submitted form. Still, we don't want any automatic INSERT/UPDATE/DELETE in the database.

The above is true, for example, when one of the fields must be computed based on the values of the other input fields. This is also true when you perform additional validation on the inserted data that standard validators cannot provide.

SQLFORM without database IO Insertion

The SQLFORM without database IO Insertion can be simply accomplished by breaking:

form = SQLFORM(db.person)
if form.process().accepted:
    response.flash = 'record inserted'

into

form = SQLFORM(db.person)
if form.validate():
    ### deal with uploads explicitly


    form.vars.id = db.person.insert(**dict(form.vars))


    response.flash = 'record inserted'

SQLFORM without database IO Updating and Deletion

The updating or deletion of SQLFORM without database IO can be simply accomplished by breaking:

form = SQLFORM(db.person, record)
if form.process().accepted:
    response.flash = 'record updated'

into

form = SQLFORM(db.person, record)
if form.validate():
    if form.deleted:
        db(db.person.id==record.id).delete()
    else:
        form.record.update_record(**dict(form.vars))
    response.flash = 'record updated'

In the case of a table with an "upload"-type field ("fieldname), both process(dbio=False) and validate() handle the upload file storage as if process(dbio=True), which is the default behaviour.

The name given to the uploaded file via web2py can be found in:

form.vars.fieldname

Frequently Asked Questions

Describe a case when we may need SQLFORM without database IO.

When one of the fields needs to be computed from the values of other input fields, this is one of the cases where SQLFORM without database IO is required.

Is web2py an MVC framework?

The Ruby on Rails and Django frameworks informed the creation of web2py. Web2py, like similar frameworks, emphasises rapid development, prefers convention over configuration, and adheres to the model-view-controller (MVC) architectural paradigm.

Which is better, web2py or Django?

Due to its smaller size, short learning curve, and lack of project-level configuration files, web2py differs from Django. Compared to PHP-based frameworks and Java-based frameworks, web2py has a significantly more explicit syntax.

What is Database Abstraction Layer?

A database abstraction layer is an API (Application Programming Interface) that allows a computer application to communicate with databases such as Oracle, SQL Server, MySQL, IBM Db2, and PostgreSQL.

Why web2py?

Server-side web development is easy to learn and lightweight, and fast.

Conclusion

In this article, we have extensively discussed how to add extra form elements and SQLFORM without database IO in web2py. 

Do you not feel eager to read/explore additional information on the subject of Web2py after reading about how to add extra form elements and SQLFORM without database IO in web2py? See the Web2py, Web2Py init,  Application creation, Web2Py Installation, and Troubleshooting to learn more.

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