Re: Getting foreign keys. - Chris McGowan - com.mysql.lists.java

18 messages in com.mysql.lists.javaRe: Getting foreign keys.

From	Sent On	Attachments
Mofeed Shahin	11 Dec 2003 22:44
Jeff Newmiller	12 Dec 2003 10:20
Chris McGowan	12 Dec 2003 10:38
Mark Matthews	12 Dec 2003 10:55
Chris McGowan	12 Dec 2003 11:52
Mofeed Shahin	14 Dec 2003 15:08
Christian Mack	17 Dec 2003 10:02
Mofeed Shahin	17 Dec 2003 14:31
Susidzaimah Pg Sulaiman	30 Jan 2004 00:38
Scott Queen	30 Jan 2004 06:43
Mike Markovich	30 Jan 2004 07:12
Susidzaimah Pg Sulaiman	31 Jan 2004 17:26
Susidzaimah Pg Sulaiman	31 Jan 2004 17:27
Scott Queen	31 Jan 2004 19:07
Keith Hatton	02 Feb 2004 01:26
Mike Markovich	02 Feb 2004 07:49
Susidzaimah Pg Sulaiman	02 Feb 2004 23:40
Susidzaimah Pg Sulaiman	03 Feb 2004 19:01

Subject:	Re: Getting foreign keys.
From:	Chris McGowan (Chri...@Colorado.edu)
Date:	12/12/2003 10:38:57 AM
List:	com.mysql.lists.java

Mofeed,

Jeff's correct. You'll need to use InnoDB tables for foreign keys to work. But it seems useless to use foreign keys unless you're using Constraints. Just add type=InnoDB to the end of your create table() syntax and it should work:

CREATE TABLE Student (Stud_ID INT) TYPE=innodb;

I messed around with your problem and couldn't get J/Connector to show anything for Foreign Keys. But then again, I'm unaware of any MySQL query/function that actually shows foreign key information, except for: SHOW CREATE TABLE table_name;

It may be a lost cause :(

On Fri, 12 Dec 2003, Mofeed Shahin wrote:

Hey guys,

I've just started to play with MySQL, and am trying to get something I wrote to talk to it, but I'm having problems getting foreign key information out of the database.

[...]

The Tables are created like so :

CREATE TABLE Student ( Student_ID INT PRIMARY KEY, First_Name varchar(50), Last_Name varchar(50), UNIQUE (First_Name, Last_Name) );

CREATE TABLE Address ( First_Name varchar(50), Last_Name varchar(50), Address varchar(50), PRIMARY KEY (First_Name, Last_Name), FOREIGN KEY (First_Name, Last_Name) REFERENCES student (First_Name, Last_Name) );

The problem is that when I do meta.getImportedKeys(...), it returns an empty set. I've tried the same thing, but using a single column foreign key, but that still returns an empty set.....

MySQL tables don't support foreign keys... the syntax just gets swallowed.

Try InnoDB tables... RTF-MySQL-M. I don't know if Connector/J will dig up the information you want, but until foreign keys are actually present you can't expect to get information on them.

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