I think that mostly databases allow only one primary key and several unique
keys.
Two type of keys allow references (by foreign keys). So, we can say that
unique keys is a king of primary key (except that Primary keys don't allow
nulls, and unique keys allow one value null).
I expect this explain
My mistake (as most of the time ;-). The very next paragraph in the MySQL
manual states:
A PRIMARY KEY can be a multiple-column index. However, you cannot create a
multiple-column index using the PRIMARY KEY key attibute in a column
specification. Doing so will mark only that single column as prim
The autobuild feature was experimental and will not be part of 1.0!
> -Original Message-
> From: Thomas Dudziak [mailto:[EMAIL PROTECTED]
> Sent: Friday, March 21, 2003 11:19 AM
> To: [EMAIL PROTECTED]
> Subject: Multiple primary keys in ojb tables
>
>
> Hi,
>
I'm no database expert so I don't relly know about this. However, quoted
from the official MySQL reference manual :
A PRIMARY KEY is a unique KEY with the extra constraint that all key
columns must be defined as NOT NULL. In MySQL the key is named PRIMARY. A
table can have only one PRIMARY KEY. If
>Sent: 21 March 2003 10:20
>To: OJB Users List
>Subject: Re: Multiple primary keys in ojb tables
>
>
>Is very common, and sometimes is mandatory to use more than
>one primary
>key in a table.
>This is the first DB I know in which it is not possible.
>
>Thomas Dudziak
Is very common, and sometimes is mandatory to use more than one primary
key in a table.
This is the first DB I know in which it is not possible.
Thomas Dudziak wrote:
Hi,
I was playing with the tutorials and with the AutoBuildDb stuff when I got
a complaint from MySQL that a CREATE TABLE statem
Hi,
I was playing with the tutorials and with the AutoBuildDb stuff when I got
a complaint from MySQL that a CREATE TABLE statement tries to define
multiple primary columns. After some searching I found that in the file
src/test/org/apache/ojb/repository_internal.xml the tables OJB_HL_SEQ and
OJB_
