On Wed, Dec 23, 2020 at 6:56 PM Guyren Howe <guy...@gmail.com> wrote:
> I’d like to put together a good video and writeup about what the… > philosophy behind relational databases is. > > Most folks, in my experience, who use relational databases don’t really > understand the basic theory or even more important the why — the philosophy > — of what a relational database is and how to get the most out of them. I > see a lot of folks trying to use SQL in an imperative manner — make this > temp table, then update it some, then make this other temp table, etc… I > see this particularly among analysts who for some reason often prefer SQL > Server. I think this is down to afaict SQL Server having an abominable > query optimizer. > I find temp tables quite helpful to get needed and consistent performance when doing large data warehouse type queries on source data especially when it isn't fully & properly normalized. Many row estimates being low because of correlation with specified client_id and sometimes having 15-25 tables involved in a report, has meant that temp tables (that are analyzed to ensure statistics are present) have seemed the best tool for the job. Perhaps that's all a hack though. I look forward to when extended statistics may help with join planning and building out a comprehensive warehouse that facilitates use of simpler queries, but for now the "imperative straight-jacket" seems to help more often than it hurts. >
