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 Data Manipulation (DML) StatementsBuilt-in Scalar Functions 

Data Type for Variables

A local variable can be of any SQL type other than an array.

  • A domain name can be specified as the type;the variable will inherit all of its attributes.

  • If the TYPE OF domain clause is used instead, the variable will inherit only the domain’s data type, and, if applicable, its character set and collation attributes.Any default value or constraints such as NOT NULL or CHECK constraints are not inherited.

  • If the TYPE OF COLUMN relation.column option is used to “borrow” from a column in a table or view, the variable will inherit only the column’s data type, and, if applicable, its character set and collation attributes.Any other attributes are ignored.

NOT NULL Constraint

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.