Check eMail Address with SQL

UDF - Check eMail Address with SQL.sql

-- UDF - Check eMail Address:
-- Parameters: ParEmail => EMail Address
-- Returns:    0 = Invalid eMail Address / 1 = valid eMail Address
--             In Release 7.5 the new Boolean Datatype could be used for the Return Value
-- Attention:  There might be better regular expression patterns for checking eMail addresses

Create or Replace Function YourSchema.CheckEmail (ParEMail Varchar(256))
       Returns Integer
   Language SQL
   Modifies SQL Data
   Deterministic
   Called On Null Input
   Set Option Dbgview = *Source
Begin
   Declare RegexPattern VarChar(256) CCSID 1208 
                        Constant '^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$';
   Declare Continue Handler For SQLEXCEPTION Return 0;
   
   Return Case When RegexP_Like(Trim(ParEmail), RegexPattern)
               Then 1
               Else 0
          End;                     
End;

Label On Routine YourSchema.CheckEmail(Varchar()) Is 'UDF - Check eMail Address';

Comment On Parameter Routine YourSchema.Checkemail (Varchar())
   (Paremail Is 'EMailAddress');
   
-- Test
Values(CheckEMail('[email protected]'));
Values(CheckEMail('[email protected]'));

There were some people having problems calling my UDF using my example.
If the UDF schema/library is in the library list (when working under System Naming Conventions)) or in the SQL Path (when working with the SQL Naming Convetions), the UDF does not have to be qualified.
If you want to call the function qualified, the test statements must look as follows:

Values(YourSchema.CheckEMail('[email protected]'); (System AND SQL Naming conventions)
Values(YourSchema/CheckEMail('[email protected]'); (System Naming Conventions only)