Question

我有一个带有两个集合的数据库。学生集合有一个名为“student_bookselections”的字段，用于保存书籍的ID。该字段的内容通常会被更改或更新。

我们如何在student_bookselections中添加或删除id？
这是一种与收藏品联系的好方法吗？

学生集合

                array(
                "student_id" => 4,
                "student_fullname" => $studentfullname,
                "student_bookselections" => 'id1,  id34, id788 ... ... id4'

                )

书籍收藏

                array(
                "book_id" => 4354,
                "book_title" => $title,
                "book_author" => $author,

                )

Answer 1

你最好有第三张桌子将学生与书籍联系起来，你当前的实施没有规范化。

Users(
    "student_id" => 4,
    "student_fullname" => $studentfullname
 )

Books(
    "book_id" => 4,
    "book_title" => $title,
    "book_author" => $author
 )

Selections(
    "selection_id" => 4,
    "student_id" => $studentid,
    "book_id" => $bookid
 )

然后，您可以定义与外键的关系以链接表，更重要的是，每行与一条信息相关。如果您想知道某个学生的所有书籍选择

mysql_query("SELECT * FROM Selections WHERE student_id = $student_id");

希望有所帮助！

Answer 2

更新

<?php

  $mongo = new Mongo();
  $db = $mongo->selectDB("Your_Database");

  $student = $db->students;

  $update = array("$set" => array("student_bookselections" => "your ids"));
  $where = array("student_id" => 4);
  $student->update($where,$update);

?>

要插入

<?php

  $mongo = new Mongo();
  $db = $mongo->selectDB("Your_Database");

  $student = $db->students;

  $insert = array("student_fullname" => "Stefan", "student_bookselections" => "your ids" );
  $student->insert($insert);

?>

要删除

<?php

  $mongo = new Mongo();
  $db = $mongo->selectDB("Your_Database");

  $student = $db->students;

  $student->remove(array("ID" => 4));

?>

<强>关系（见Crhis的帖子）

Users(
    "student_id" => 4,
    "student_fullname" => $studentfullname
 )

Books(
    "book_id" => 4,
    "book_title" => $title,
    "book_author" => $author
 )

Selections(
    "selection_id" => 4,
    "student_id" => $studentid,
    "book_id" => $bookid
 )

选择此关系

<?php

  $mongo = new Mongo();
  $db = $mongo->selectDB("Your_Database");

  $selection = $db->selections;

  $res = $student->find(array("student_id" => $student_id));

?>

我们如何更新学生的选择？

2 个答案: