field from another database when

I want to copy the content of a field in another database into a formfield when another formfield matches.
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When the email-address in the other database also exist than the content auf startnumber field should be inserted in the formfield startnumber
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The read data in the form action works well to find out if there exist the same email-address in the other database but how can i transfer the content from the external startnumber-field into my actual form?

Set the value of the field to {var:read_data_action_name.model.fieldname} and reload the field when the email field is changed. One of the demo forms should help you further.

thanks again for your help. I didnt know how to solve the reload after changing the email field but i solved it with to pages - on the first only the email and than on the second side the others with the filled content if the email was found.