如何使用 php jquery 加速数千个 php 循环

Question

Recently I have develop an apps for processing student result. The algorithm is below:

Algorithm:

get list of all students from mysql

  if found

    get list of subject from mysql

      get sum of marks from mysql for each student and subject

      calculate pass,fail,grade point etc.
      insert total marks into another table

    //end subject list

  error msg if no student

// end

this takes huge time.

now I like to speed up with jQuery.

For example,

load all student id and subject id into jQuery array. then send a request to PHP to process result using jQuery loop or any other way.

Answer 1

What you are saying does not make much sense. However, from your algorithm description above it looks like you are selecting students, subjects, marks in loops and hitting your DB for each student's subject's marks. Instead, use table joins ( left join , inner join , etc.).

SELECT s.*, sb.*, SUM(m.value)
FROM students AS s
  LEFT JOIN subjects as sb ON s.id = sb.student_id
  INNER JOIN marks AS m ON sb.id = m.subject_id
GROUP BY s.id, sb.id

With this query you are replacing your 1000 queries with one in database calculation query. MySql will run the query in more optimised manner and require less resources.

Answer 2

It's pretty hard to say what is your real problem, but it sounds like first thing you should do is to avoid those loops. Maybe you could move part of this logic to the database using some stored procedures?

Having loads of database shots may affect performance significantly.