Certainly, it's called making a unique index on the field(s) you want to keep
unique.
Hope that helps.
j- k-
On Wednesday 07 July 2004 12:48 pm, John Mistler said something like:
Is there a way to do an INSERT on a table only if no row already exists
with the same info for one or
Create a unique index on each column that you don't
want to be duplicated.
create UNIQUE index table_u1 on table(some_column)
--- John Mistler [EMAIL PROTECTED] wrote:
Is there a way to do an INSERT on a table only if no
row already exists with
the same info for one or more of the columns as
(obviously put in the appropriate column names etc for your data structure!)
Cheers,
Matt
-Original Message-
From: Joshua J. Kugler [mailto:[EMAIL PROTECTED]
Sent: 07 July 2004 22:22
To: [EMAIL PROTECTED]
Subject: Re: INSERT DISTINCT?
Certainly, it's called making a unique index
2004 22:22
To: [EMAIL PROTECTED]
Subject: Re: INSERT DISTINCT?
Certainly, it's called making a unique index on the field(s) you want
to
keep
unique.
Hope that helps.
j- k-
On Wednesday 07 July 2004 12:48 pm, John Mistler said something like:
Is there a way to do an INSERT on a table only
I am not certain from the documentation whether it is advisable to create a
unique multi-column index on two columns that are already individually
indexed. The individual indexes I assume I need for when I do a SELECT on
those particular columns. The multi-column one I need for the reasons
is going to generate a duplicate key error when duplicates
are found.
Hope this clarifies some things for you.
Lachlan
-Original Message-
From: John Mistler [mailto:[EMAIL PROTECTED]
Sent: Thursday, 8 July 2004 12:27 PM
To: [EMAIL PROTECTED]
Subject: Re: INSERT DISTINCT?
I am not certain
direct address, this way everyone can keep track of the discussion.
-Original Message-
From: John Mistler [mailto:[EMAIL PROTECTED]
Sent: Thursday, 8 July 2004 1:24 PM
To: Lachlan Mulcahy
Subject: Re: INSERT DISTINCT?
Thanks, Lachlan! One other thing I am wondering: given two columns (a,b
At 19:26 -0700 7/7/04, John Mistler wrote:
I am not certain from the documentation whether it is advisable to create a
unique multi-column index on two columns that are already individually
indexed. The individual indexes I assume I need for when I do a SELECT on
those particular columns. The
Paul,
What about the case where column A is a foreign key?
In that case would you be forced to keep the index on
column A or could you use the A,B index since A is the
left most prefix?
Tripp
--- Paul DuBois [EMAIL PROTECTED] wrote:
At 19:26 -0700 7/7/04, John Mistler wrote:
I am not
From the manual
http://dev.mysql.com/doc/mysql/en/InnoDB_foreign_key_constraints.html:
In the referencing table, there must be an index where the foreign key
columns are listed as the first columns in the same order. In the
referenced table, there must be an index where the referenced columns
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