Don't understand creation statement's answer

Hi,

In the long term I'm willing to construct a Little Java application that
runs a library. I was looking to create a few table & connect them
according to a non existing model . To create the Author table here's
what I thought doing for a table that should only contain The Name & the
Surname of the Author (once per Author).


<snip>
tsmets=> create sequence author_seq;
CREATE  

tsmets=> create table author ( 
tsmets=>     author_id numeric primary key default
nextval('author_seq'),  
tsmets=>     name char(25) not null, 
tsmets=>     surname char(25) not null
tsmets=>     );
NOTICE:  CREATE TABLE/PRIMARY KEY will create implicit index
'author_pkey' for table 'author'
CREATE
tsmets=> \d author                             Table "author"Attribute |     Type      |                   Modifier
-----------+---------------+----------------------------------------------author_id | numeric(30,6) | not null default
nextval('author_seq'::text)name      | char(25)      | not nullsurname   | char(25)      | not null
Index: author_pkey
tsmets=>                       
</snip>

Now the question is :
What is the meaning of the following statement in the table description
?
Attribute |     Type      |                   Modifier
-----------+---------------+----------------------------------------------author_id | numeric(30,6) | not null default
nextval('author_seq'::text)

Why was my author_id changesdin a "nextval('author_seq'::text)".
There's no text here ?

That for highlighting the meaning of this ?

Thomas,



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Sun Dec 17 19:42:31 CET 2000

Thomas SMETS                        e-mail : tsmets@altern.org
Av. de la Brabançonne 133 / 3       Tel. : +32 (0)2 742. 05. 94.
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