Subject RE: [firebird-support] New substring() extension usage issue
Author Alan McDonald
> Hi all,
> I am attempting to use SUBSTRING to iterate through a string pulling
> out numerals only within the context of a table trigger.
> Unfortunately, it appears that the variable i within the substring
> function call is an unknown token. A semi-colon is similarly
> unknown. This seems in contradiction to the documentation which
> states "<pos> must evaluate to an integer" and i is at <pos>.
> Any ideas? Here is my trigger definition, which if the i at <pos> is
> substuted for a constant (eg. 5) compiles and runs. Also, if anyone
> knows a better way to return numbers only within a phone_no string
> (without a UDF) please feel free to hit me with it.

Are you sure about the need to validate your data at the server? Isn't this
best dealt with at the client with mask edit and other routines?