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New Oracle explicit defaults
Donald K. Burleson |
In Oracle Data Definition Language (DDL), the Oracle DBA has the ability to assign default values to any data column. This feature removes the tedium of naming all of the column values for every INSERT statement.
Create table
Student
(
student_id number,
student_rank varchar2(3) DEFAULT ‘FRESHMAN’
);
When using a default value, the developer would simply omit the default column:
Insert into student (student_id) values ‘Jones’;
In the above SQL it is not clear that the default value of ‘Freshman’ was inserted into the table. Starting in Oracle9i, the DEFAULT keyword can be used to explicit assign the columns default value during any INSERT or UPDATE statement:
insert into
student
values
('jones', DEFAULT);
update
student
set
student_rank = DEFAULT
where
student_id = 12345;
If you like Oracle tuning, you might enjoy my latest book “Oracle Tuning: The Definitive Reference” by Rampant TechPress. It’s only $41.95 (I don’t think it is right to charge a fortune for books!) and you can buy it right now at this link:
http://www.rampant-books.com/book_2003_1_oracle9i_sga.htm
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