You can use a named pipe to unload data from the database
to external tables.
To use named pipes to unload data to external tables,
follow these steps:
- Specify the named pipe in the DATAFILES clause
of either the CREATE EXTERNAL TABLE statement
or the SELECT INTO EXTERNAL statement
of SQL.
DATAFILES ("PIPE:/usr/local/TAPE")
- Create the named pipes that you specified in the DATAFILES clause. Use operating-system
commands to create the named pipes.
- Open the named pipes with a program that writes to the
named pipe.
- Unload data to the named pipe.
CREATE EXTERNAL TABLE emp_ext
( name CHAR(18) EXTERNAL CHAR(20),
hiredate DATE EXTERNAL CHAR(10),
address VARCHAR(40) EXTERNAL CHAR(40),
empno INTEGER EXTERNAL CHAR(6) )
USING (
FORMAT 'FIXED',
DATAFILES
("PIPE:/usr/local/TAPE")
);
INSERT INTO emp_ext SELECT * FROM employee;
Important: If you do not create and open the named
pipes before you execute the SELECT or INSERT statement, the unload
fails with the ENXIO error message (no such device or
address).