I'm trying to find a regex pattern for a validation rule on an opportunity that will allow dd/mm/yyyy one or more lines in a long text field named Dates_offered__c.
For example, I want to allow:
but not allow
also I do not want to allow any letter characters, it should be numbers and "/" only.
This means the text field should always have this format
At the moment I have this but it doesn't work:
not(REGEX( Dates_offered__c , "(0[1-9]|[0-9]|3)[/](0[1-9]|1)[/]\\d\\d\\d\\d \r\n"))