Tag: Coding

I happened upon a customer who left me in awe and admiration. The reason: excellent comments for their SQL code.

I list four major places where SQL comments are helpful. I’ll use the sakila database. It is originally scarcely commented; I’ll present it now enhanced with comments, to illustrate.

Table definitions

The CREATE TABLE statement allows for a comment, intended to describe the nature of the table:

CREATE TABLE `film_text` (
 `film_id` smallint(6) NOT NULL,
 `title` varchar(255) NOT NULL,
 `description` text,
 PRIMARY KEY (`film_id`),
 FULLTEXT KEY `idx_title_description` (`title`,`description`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COMMENT='Reflection of `film`, used for FULLTEXT search.'

It’s too bad the comment’s max length is 60 characters, though. However, it’s a very powerful field.

Column definitions

One may comment particular columns: Continue reading » “SQL: good comments conventions”