My application has a subroutine which will generate an 8-character random string of letters and numbers, prefixed by an optional string provided by the caller.
That can be quite a performance killer if your database stores rows in primary key order. Storing rows in primary key order has some advantages: it saves on the overhead size of the index, and new rows will always go on the end: no need to split pages, and less rebalancing of the index. Furthermore, I prefer to keep my rows as small as possible (smaller rows means more rows/page, more rows/page means less pages needed, less pages needed means less disk I/O, less disk I/O means better performance). If I can use a tinyint as primary key, I use a tinyint. Else, a mediumint. But even a 4-byte integer is less than an 8 character string. And even using a data column as primary key is acceptable.
The advantage of this approach is that “every integer looks exactly like every other integer, but monikers never, ever will.” If the wrong kind of moniker is in some column, you can immediately detect it by eye. Or, by a query, e.g.: 
    select dataset_moniker from datasets where dataset_moniker not lik
+e 'dataset_%'

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How does that rhyme with what you write in your first paragraph: It should be a column whose values are utterly devoid of business or other meaning. If your primary column is utterly devoid of any business or other meaning, you would never use literals in your queries. Your primary columns would only show up in joins. Your example would never be issued.

In reply to Re: An improved technique for database primary keys by JavaFan
in thread An alternate technique for database primary keys by locked_user sundialsvc4

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