NOT NULL

For local variables, you can specify the NOT NULL constraint, disallowing NULL values for the variable.If a domain has been specified as the data type and the domain already has the NOT NULL constraint, the declaration is unnecessary.For other forms, including use of a domain that is nullable, the NOT NULL constraint can be included if needed.

Unless specified, the character set and collation of a string variable will be the database defaults.A CHARACTER SET clause can be specified to handle string data that needs a different character set.A valid collation (COLLATE clause) can also be included, with or without the character set clause.