Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

MySQL Bad Idea #573

DZone's Guide to

MySQL Bad Idea #573

· Big Data Zone
Free Resource

Need to build an application around your data? Learn more about dataflow programming for rapid development and greater creativity. 

This is MySQL’s Bad Idea #573 (after #384, which I’ve blogged about before) I’ve just had a terrible experience with a bug report from the jOOQ User Group, related to escaping of backslashes in string literals in MySQL. First, I thought to myself, whatever. SQL doesn’t escape backslashes. The only escape character within a string literal according to the early SQL standards is the quote as in quote quote. Citing from SQL-1992 (slightly simplified):

<character string literal> ::=
    <quote> [ <character representation>... ] <quote>

<character representation> ::=
    <nonquote character>
  | <quote symbol><nonquote character> ::= !! See the Syntax Rules.
<quote symbol> ::= <quote><quote>

Alright? Crystal clear. There’s no escaping other than <quote><quote>

The only time when you will need to be able to escape something is with the LIKE predicate, in case you want to escape % and _ symbols. You can then use the ESCAPE clause:

<like predicate> ::=
    <match value> [ NOT ] LIKE <pattern>
    [ ESCAPE <escape character> ]

I have now learned, that MySQL (and of course MariaDB) unlike any other database also support quoting with backslashes, similar to Java and other languages. That’s not a problem per se, although from a cross-vendor compatibility perspective, it’s quite nasty. But then, I’ve discovered there is a flag called NO_BACKSLASH_ESCAPES:

This just reminds me of PHP’s horrible magic quotes. In fact, combine arbitrary configurations of PHP and MySQL on your server and good luck to you of ever getting string literals right. Sigh.

Check out the Exaptive data application Studio. Technology agnostic. No glue code. Use what you know and rely on the community for what you don't. Try the community version.

Topics:

Published at DZone with permission of Lukas Eder, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

THE DZONE NEWSLETTER

Dev Resources & Solutions Straight to Your Inbox

Thanks for subscribing!

Awesome! Check your inbox to verify your email so you can start receiving the latest in tech news and resources.

X

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}