On Wed, Dec 2, 2015 at 4:29 PM, R Smith <rsmith at rsweb.co.za> wrote: > > Personally I use VARCHAR(Len) in table column definitions - simply because > my schema is then directly interchangeable with MySQL/PostGres and the > SQLite query planner sometimes notes that length when considering data > shape - but for data purposes, SQLite doesn't care and neither do any > wrappers I know of. Also, I can't imagine Excel would have an issue, > whether referencing a data object via VB Script or OLE DB table import etc, > I have never seen it matter in Excels 2003 through 2013.
I discourage this kind of usage because it means that in some distant future when someone has to make things work with a different database engine, they have to grind through and check every weirdo VARCHAR(73) and MEDIUMBIGINT declaration someone put in, because none of them have ever been tested with range enforcement enabled. So where someone meant "VARCHAR(256)" but actually typed "VARCHAR(6)", will your code suddenly start throwing clean errors which immediately suggest where to look, or will it just muddle through corrupting your data? There can certainly be subtle issues in any type, but my experience is that when you're trying to decode someone's code, it's easiest when the code says what is actually happening, not what it wishes were happening! Of course, if you are _currently_ writing cross-platform code, absolutely write the cross-platform code! And I will agree that the above position has some issues when faced with things such as INT being 32 bits on some platforms, which I guess would argue for using BIGINT and BIGTEXT. Unless you need VARCHAR(MAX) or LONGTEXT, but maybe MEDIUMTEXT is more portable ... and pretty soon you give up and just circle back to not decorating with unused/unchecked type annotations. -scott
