SAIL form data to submit into Database

Plz refer forum.appian.com/.../Write_to_Data_Store_Entity_Smart_Service.html
forum.appian.com/.../Write_to_Data_Store_Entity_Smart_Service.html

The traditional way is to save the data into Rule Inputs, which you then feed out into similarly named AC variables in a User Input Task in a process model, and upon form submit have those saved into process PV variable(s), which you can then write to database using a Write to Data Store node.
To get any more specific, it would be necessary for you to describe more about what you do or don't already have set up.

@jrmprasad we have many approaches to do this

1. Capture the form field data into rule input and configure the same interface under user input task, create user input and use ac! While passing the value of rule input for interface under form tab of user input task node, followed by write to data store entity smart service in process model, under input tab of write to data store entity, choose the type as rule input CDT data type, and create a input of type same CDT and pass the value as the process variable I.e. PV! which holds interface data

2. We can also directly call the smart service function, under saveInto of submit button, use a!writetodatastoreentity() function, where refer a constant as first parameter for entity type I.e. entityType, this constant will refer same data type as rule input
Second parameter for this function will be your rule input I.E ri!...

This both approaches can persist the data into dB

3. We can create a process model having write to data store entity smart service, create a process variable of type same CDT as rule input as parameterized, use the same process variable under input tab of write to data store entity smart service.

Under saveInto of submit button of interface, use a!startProcess() function
Here first parameter I.e. processModel will be a constant which will refer the above process model,
And pass the rule input for next parameter I.e. process parameters as

{myInput: ri!mycdtdata}

This can also do your job

For more details about write to data store entity smart service, please refer the link shared by @Vinod