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Legal Studies如何在 MongoDB 中更新多份文档？
您需要使用 multi:true 来更新多份文档。首先，我们用文档来创建集合 -
> db.multiUpdateDemo.insertOne({"ClientName":"John","ClientAge":29});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cda5bc0b50a6c6dd317adc8")
}
> db.multiUpdateDemo.insertOne({"ClientName":"Carol","ClientAge":31});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cda5bc1b50a6c6dd317adc9")
}
> db.multiUpdateDemo.insertOne({"ClientName":"John","ClientAge":39});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cda5bc3b50a6c6dd317adca")
}
> db.multiUpdateDemo.insertOne({"ClientName":"John","ClientAge":41});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cda5bc5b50a6c6dd317adcb")
}
> db.multiUpdateDemo.insertOne({"ClientName":"David","ClientAge":35});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cda5bc6b50a6c6dd317adcc")
}以下是对集合中显示所有文档的查询，通过 find() 方法来实现 -
> db.multiUpdateDemo.find().pretty();
这将生成以下输出 -
{
"_id" : ObjectId("5cda5bc0b50a6c6dd317adc8"),
"ClientName" : "John",
"ClientAge" : 29
}
{
"_id" : ObjectId("5cda5bc1b50a6c6dd317adc9"),
"ClientName" : "Carol",
"ClientAge" : 31
}
{
"_id" : ObjectId("5cda5bc3b50a6c6dd317adca"),
"ClientName" : "John",
"ClientAge" : 39
}
{
"_id" : ObjectId("5cda5bc5b50a6c6dd317adcb"),
"ClientName" : "John",
"ClientAge" : 41
}
{
"_id" : ObjectId("5cda5bc6b50a6c6dd317adcc"),
"ClientName" : "David",
"ClientAge" : 35
}以下是执行多更新的查询。现在，3 个客户端的 ClientName “John”将使用以下查询来更新年龄 -
> db.multiUpdateDemo.update({'ClientName': 'John'}, {$set: {'ClientAge': 34}}, {multi: true});
WriteResult({ "nMatched" : 3, "nUpserted" : 0, "nModified" : 3 })让我们再次检查文档 -
> db.multiUpdateDemo.find().pretty();
这将生成以下输出 -
{
"_id" : ObjectId("5cda5bc0b50a6c6dd317adc8"),
"ClientName" : "John",
"ClientAge" : 34
}
{
"_id" : ObjectId("5cda5bc1b50a6c6dd317adc9"),
"ClientName" : "Carol",
"ClientAge" : 31
}
{
"_id" : ObjectId("5cda5bc3b50a6c6dd317adca"),
"ClientName" : "John",
"ClientAge" : 34
}
{
"_id" : ObjectId("5cda5bc5b50a6c6dd317adcb"),
"ClientName" : "John",
"ClientAge" : 34
}
{
"_id" : ObjectId("5cda5bc6b50a6c6dd317adcc"),
"ClientName" : "David",
"ClientAge" : 35
}
更新于：2019-07-30
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