Declare your unique index to be a primary key. $sth->execute will fail if you try to insert a duplicated primary key.

mysql> create table trial (id varchar(5) primary key, perl_mod varchar
+(30), summary varchar(255));
Query OK, 0 rows affected (0.06 sec)

mysql> insert into trial set id='aaaaa',
> perl_mod='CGI',
> summary='Essential';
Query OK, 1 row affected (0.04 sec)

mysql> insert into trial set id='aaaab',
> perl_mod='DBI',
> summary='Essential';
Query OK, 1 row affected (0.00 sec)

mysql> insert into trial set id='aaaab',
> perl_mod='Lingua__Romana__Perligata',
> summary='Fun';
ERROR 1062: Duplicate entry 'aaaab' for key 1
mysql>
[download]

After Compline,
Zaxo

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.