在 Mongo 中嵌套 $pull 命令

Question

我试图从多个数组中删除一个值，而不必发出多个 Mongo 命令。我一定是语法不正确，如有任何帮助，我们将不胜感激。

当我尝试时：

update = BCON_NEW("$pull", 
        "{", 
            "files.$.like", BCON_UTF8 (account_id), 
        "}",
        "{", 
            "files.$.hate", BCON_UTF8 (account_id), 
        "}",
        "{", 
            "files.$.love", BCON_UTF8 (account_id), 
        "}",
        "{", 
            "files.$.funny", BCON_UTF8 (account_id), 
        "}",
        "{", 
            "files.$.sad", BCON_UTF8 (account_id), 
        "}",
        "{", 
            "files.$.anger", BCON_UTF8 (account_id), 
        "}",
        "{", 
            "files.$.kiss", BCON_UTF8 (account_id), 
        "}"
        );

如果我将它简化为以下它有效，它就会失败：

update = BCON_NEW("$pull", 
        "{", 
            "files.$.like", BCON_UTF8 (account_id), 
        "}"
        );

Answer 1

$pull 对其后面的文档进行操作。参见 MongoDB Documentation on $pull。我以前从未见过 BCON 符号，所以我可能是错的，但如果我理解正确的话，我相信你的代码创建的文档应该是这样的：

{
    $pull: { "files.$.like": BCON_UTF8 (account_id) } //Here's the end of your $pull document,
    { "files.$.hate": BCON_UTF8 (account_id) },
    { "files.$.love": BCON_UTF8 (account_id) },
    ...
},

相反，我认为你想要这样的东西（我没有测试过）：

update = BCON_NEW("$pull", 
    "{", 
        "files.$.like", BCON_UTF8 (account_id),  
        "files.$.hate", BCON_UTF8 (account_id), 
        "files.$.love", BCON_UTF8 (account_id), 
        "files.$.funny", BCON_UTF8 (account_id), 
        "files.$.sad", BCON_UTF8 (account_id), 
        "files.$.anger", BCON_UTF8 (account_id), 
        "files.$.kiss", BCON_UTF8 (account_id), 
    "}"
    );

在 Mongo 中嵌套 $pull 命令

nesting $pull commands in Mongo

mongodb

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mongo-c-driver