mysql - PHP mysql_query nested loops or duplicate reference -


i have relatively simple program displays information , activity of users - due architecture of program requires referencing lots of different data in different ways.

for example have users can have different levels of status within different or multiple groups , these groups can have own statuses. my question best practices referencing lots of data , speed/logic of code.

  • option - have several instances data within data base , reference , update individually on several tables using simple statements , queries.
  • option b - use many nested queries , if statements retrieve multiple bits of data

simply put: is best use lots of nested queries within loops , if statements, or break different sets of data in database , reference them individually? i'm after reliability , speed rather technical wizardry.

i know may specific program, know general opinion of developers out there , experience without getting deep in examples.

joins can expensive because of heavy temp table produced in middle of operation. accurate data extraction can more logical in case. dependent data model, tables, references, insert rate, update rate, query rate on tables. maybe queries should written using joins, maybe of them better written using procedures.


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