i have field firstname,middlename,lastname,age,gender. i would like to save all of it in databse profile field. there is no firstname,middlename,lastname,age,gender in db, only profile field.
Store the different fields in an array after validation, and either serialize() or json_encode() that array before you store the result in the database?
That would be a better option, but requires ORM. And in case of ORM, you can use the typing observer to do the serialisation or json encoding for you. But that wasn't the question.
This suggests the use of Simpleauth, which stores data in a profile field. But on the other hand, for that you don't need to know how to store it, as Auth will take care of that. Ormauth on the other hand uses EAV instead of the profile field.
So perhaps more info about the context is needed to give a correct answer?