string mysql_field_flags (int result, int field_offset)
mysql_field_flags() returns the field flags of the specified field. The flags are reported as a single word per flag separated by a single space, so that you can split the returned value using explode().
The following flags are reported, if your version of MySQL is current enough to support them: "not_null", "primary_key", "unique_key", "multiple_key", "blob", "unsigned", "zerofill", "binary", "enum", "auto_increment", "timestamp".
For downward compatibility mysql_fieldflags() can also be used.