Several characteristics provide information about the nature of data use by the routine.

·CONTAINS SQL indicates that the routine does not contain statements that read or write data.

·NO SQL indicates that the routine contains no SQL statements.

·READS SQL DATA indicates that the routine contains statements that read data, but not statements that write data.

·MODIFIES SQL DATA indicates that the routine contains statements that may write data.

CONTAINS SQL is the default if none of these characteristics is given explicitly. These characteristics are advisory only. The server does not use them to constrain what kinds of statements a routine will be allowed to execute.