Values are specified (extended_value_spec) using one of the keywords DEFAULT or STAMP or by specifying the values (value spec: Literals, parameter specifications, key words and so on).
<extended_value_spec> ::= DEFAULT | STAMP | <value_spec>
<value_spec> ::= <literal>
| USER | USERGROUP
| SYSDBA | CURRENT_SCHEMA | UID
| DATE | TIME | TIMESTAMP
| UTCDATE | TIMEZONE | UTCDIFF
| TRUE | FALSE
SQL Tutorial, Number Generators for Tables
The DEFAULT keyword can be used in a DEFAULT predicate.
The database system is capable of generating unique values. These comprise a series of consecutive numbers starting at X'000000000001'. The values are assigned in ascending order. There is no guarantee that a sequence of values is uninterrupted. The STAMP key word returns the next value generated by the database system.
If the user wants to find out the generated value before it is applied to a column, the following SQL statement must be used: NEXT STAMP statement
Specification of the NULL value
Specification of the database system administrator
Specification of current schema.
Identification of the current user. This DEFAULT specification can only be specified with numeric data type and a minimum of 10 places before the decimal point.
NEXTVAL specifies the next available value that is created by the implicit number generator, which was defined by the sequence [<schema_name>.]<sequence_name> .
CURRVAL shows the current value generated by the number generator [<schema_name>.]<sequence_name> within the database session.
Last value assigned in the current database session for the serial column in the table table_name.
Current UTC time stamp (Greenwich Mean Time)
Time difference in hours in the format hhmmss (in data type FIXED(6)) between your local time value and the UTC time value.
Time difference in hours (in data type FIXED(4,2)) between your local time and the UTC time value.
Corresponding value of a column of the data type BOOLEAN
Identification of the current transaction. This is a value of data type CHAR(6) BYTE.