mongodb數據庫多表查詢

原創 如鹰展翅上腾 2020-06-24 12:58

mongodb數據庫多表查詢方式大致分爲兩種

  • ref…與population的形式。這一種僅僅適用於一對多的關係表中，並且ref自動關聯另一個表的_id字段
  • aggregate…$lookup的形式適用於任何形式，包括一對多，多對一
  • 如何實現一對多的呢？在““多的表”中關聯“少的表”的唯一值
  • 如何實現多對多呢？互相關聯對方的唯一值
  • 另外在設置表時，字段唯一(unique)不起效果，把表刪掉重新刪掉創建表即可
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