thanks!! that helps greatly!

I guess I should have read my oracle documentation.

But your examples helped me to really understand what was going on.

Thanks again!

But when i was using a wizard for creating table there wasn`t any boolen type for data. Where i can find it...
Thanx

Oracle allows Boolean data type in PL/SQL. But it can not be used as a data type for a column.

I know this kinda late maybe, but just thought maybe it helps others by adding this comment:

In Oracle you can set up a check constraint to sort of emulate the boolean idea e.g.

CREATE TABLE table_name
(
 column_name CHAR CHECK (column_name IN ('Y','N'))
);


or you can add a check constraint to an existing table e.g.

ALTER TABLE table_name ADD CONSTRAINT test_bool CHECK
(
 column_name IN('Y','N')
);

This of course depends on the column type you did setup in the table.

for the rest, there is a specific BOOLEAN type in PL/SQL when you declare you variable e.g.

DECLARE

variable_name BOOLEAN DEFAULT [FALSE/TRUE];

BEGIN
...
END;
/

Cheers
René