How to generate a 9 digit number

Question

I'm trying to use php to generate a 9 digit number that does not start with a 0 and is separated by dash every third number.

e.g. 102-394-458

I'm also debating whether

• to store it as a number or do the formatting on the front end
• or to store it as a number and do the formatting on the backend
• or to just store the dashes in the database as well

Of course the choice will affect how the number is generated.

Answer 1

implode('-',str_split(rand(100000000,999999999),3))

Generally, it's probably better simply to store as a number, and format it with the - only for display purposes