新版不允許 unique index 在重複情況下建立因為他也不知道重複資料要怎麼處理所以清除重複後再建吧以下讨论帖，请参考： <a href="https://link.segmentfault.com/?enc=c5gimYXmeDlClSA9wWflOA%3D%3D.J%2Bo7oibNSsKtP%2BoEhYZwFJnby2DfKYWyImq75nNDCmx3bnK13tyU7DGbSLb%2FYj4SEk4ehl3CxtcT1CHuj2YvFwVkUisPNlyW6f1P2nJ53fOAijGwkl2hVt8Yll%2BzdYE65LYhu9bTC5dGppNaOLDxnBUx4WOCoWuHci%2BhHl2lMDxbLGtNYuiKY5iHqL5JTbPFGAQa%2FO7VceBaiNpGS9Hh0pofaqsAhvC6Yn8sAM37fzH1ruXYifLC1xq%2BD8G%2BEeRpBYrqaU5EJgSvwM6TvDnpJIijHCo6SxD9lIiumKpfIxw3WLI5RCTvhwRcK0aWG6Lv" rel="nofollow" target="_blank">http://forum.foxera.com/mongo...