Form Actions - Validate
An application that gives a free ride to input incorrect data is useless.
By default, Zoho Creator supports validation for an adequate number of
field types. You can specify the constraints for the fields you are defining
while creating a form. For example, if you define a field to be of type
Email, Zoho Creator checks if the data entered in the form for that field
is a valid emailid, else it will display an error message to the user.
In addition to the default validation, Zoho creator allows you to write
action scripts for custom validation which is called when a user submits
the form to the server, before the user data is stored in the database.
The script runs on the server side, and it has access to all the inputs
the user entered. The syntax for the user input is input.<variable_name>
as the examples below indicate.
The default action of validate is to submit the data, so you have to
do a cancel submit if you want to stop a form from being submitted.
You can also choose to provide proper alert message to the user
while cancelling. The same form is then shown to the user to re-enter
the data.
The Validate action scripts are executed when a new form data is submitted
or when an existing record is modified and submitted or when an existing
record is deleted.
Syntax
Validate Form Action - On Add: The validate form action
script written in the actions -> on add block within the Submit
button is executed when a new form data is submitted. This script is
executed before the new user data is stored in the database.
actions
{
on add
{
Submit
(
type = submit
displayname = "Submit"
on validate
{
// write validate form action to be executed when a new form data is submitted
.............
{
// specify alert message if not valid and cancel submission
alert "<Specify alert message>";
cancel submit;
}
}
)
}
}
|
Validate Form Action - On Edit : The validate form action
script in the actions -> on edit block within the Update
button is executed when an existing record is modified and submitted.
This script is executed before the modified user data is stored in the
database.
actions
{
on edit
{
Update
(
type = submit
displayname = "Update"
validate
{
/
............
{
alert "<Specify alert message>";
cancel submit;
}
}
)
}
}
|
Validate Form Action - On Delete : The validate form action
script in the actions -> on delete block is executed
when an existing record is submitted for deletion. This script is executed
before the user data is deleted from the database.
actions
{
on delete
{
on validate
{
...............
{
alert "<Specify alert message>";
cancel delete;
}
}
}
|
Examples
To validate if a field value falls
within a specified range
In the following sample, if the value specified in the age field is
less than 20 or greater than 100, the submit action will get cancelled.
on add
{
Submit
(
type = submit
displayname = "Submit"
on validate
{
if (input.DateOfBirth.getYear() > zoho.currentdate.getYear())
{
alert "Enter valid Date of Birth";
cancel submit;
}
}
)
}
on edit
{
Update
(
type = submit
displayname = "Update"
on validate
{
if (input.DateOfBirth.getYear() > zoho.currentdate.getYear())
{
alert "Enter valid Date of Birth";
cancel submit;
}
}
)
}
|
To check for duplication of records
- on add
In the below example, if the same team member is added more than once,
the submit action will get cancelled.
on add
{
Submit
(
type = submit
displayname = "Submit"
on validate
{
if (count(team_member[name == input.name]) > 0)
{
alert "Name already exists";
cancel submit;
}
}
)
}
|
where,
team_member [name == input.name] - selects all the team_members
whose name is equal to the name currently entered.
input.name - it is the value for the field "name" given
by the user while submitting the form
count - count operator returns the number of team members whose
name is equal to this.name
Related Links
Alert
Cancel Submit
Tips & Tricks - Validating
Form Data
Tips & Tricks -
Deleting child records (using on delete -> validate script)
