If you need to convert a TEXT column to a BYTEA column, you can use a cast expression to do the work:

ALTER TABLE mytable ALTER COLUMN col TYPE bytea USING
  decode(replace(col, '\\', '\\\\'), 'escape');

Note that altering the column type of a column is only supported beginning with PostgreSQL version 8.0. For more information, see the manual.

Consider the following schema:

CREATE TABLE loadtest (
    pkey int(11) NOT NULL auto_increment,
    name varchar(20),
    exam int,
    score int,
    time_enter timestamp(14),
    PRIMARY KEY (pkey),
);

And the data you need to load:

'name22999990',2,94
'name22999991',3,93
'name22999992',0,91

Running this query would load the data into the columns name, exam, score:

mysql> LOAD DATA INFILE '/tmp/out.txt' INTO TABLE loadtest
    -> FIELDS TERMINATED BY ',' (name,exam,score);

** Note: This tip borrowed from the Linux Gazette. You can read the complete article at http://www.linuxgazette.com/node/9059.

Use these queries to change the structure of a DOMAIN constraint:

ALTER DOMAIN foo DROP CONSTRAINT bar;
ALTER DOMAIN foo ADD CONSTRAINT bar CHECK (VALUE = 'baz'::text);