Just wondering if anyone who knew the answer to this might have missed it
before -- sorry to keep nagging but I really need to find out how, or
whether, you can determine which fields in a table are foreign keys
referencing another table.
Is it not possible to determine, after a table is created, what fields in
the table are foreign keys? For a MyISAM table (where referential
integrity is not enforced), is this information even retained?
-Bennett
At 04:53 AM 11/13/2001 -0800, you wrote:
>I created the "persons" and "shirts" tables as described in the MySQL
>tutorial:
>
>http://www.mysql.com/doc/e/x/example-Foreign_keys.html
>
>such that the "owner" field in shirts is a foreign key referencing the
>"persons" table. However, "describe shirts" does not indicate that the
>field is a foreign key: (may have to widen mail viewer window to view the
>following table)
>
>mysql> describe shirts;
>+-------+---------------------------------------------+------+-----+---------+----------------+
>| Field | Type | Null | Key |
>Default | Extra |
>+-------+---------------------------------------------+------+-----+---------+----------------+
>| id | smallint(5) unsigned | | PRI |
>NULL | auto_increment |
>| style | enum('t-shirt','polo','dress') | | |
>t-shirt | |
>| color | enum('red','blue','orange','white','black') | | |
>red | |
>| owner | smallint(5) unsigned | | |
>0 | |
>+-------+---------------------------------------------+------+-----+---------+----------------+
>4 rows in set (0.00 sec)
>
>How do I find out which fields are foreign keys?
>
>For that matter, in a MyISAM table, what difference does it make whether
>you specify that a given field is a foreign key referencing another table
>-- as opposed to just an integer field with the same data type as the key
>field of another table? Since referential integrity is not enforced with
>MyISAM tables, does it not make any difference whether I tell it that a
>field is a foreign key? Is that information discarded entirely? (Which
>would explain why "describe" doesn't show it.)
>
>The only reason I wanted to know whether a given field was a foreign key,
>was because I'm hammering together my own Web-based interface to MySQL
>tables, and I was hoping that when the table contents are rendered in an
>HTML table and a given field is a foreign key, I can have its value
>hyperlinked to the appropriate row in the table that it references.
>
> -Bennett
>
>[EMAIL PROTECTED] http://www.peacefire.org
>(425) 649 9024
>
>
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