只删除 MongoDB 中的一个文档？
要仅删除单个文档，请remove()在MongoDB中使用。让我们首先创建一个包含文档的集合-
> db.removeOnlyOneDocumentDemo.insertOne({"FirstName":"John","LastName":"Smith"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cc6ca2f9cb58ca2b005e674")
}
> db.removeOnlyOneDocumentDemo.insertOne({"FirstName":"Carol","LastName":"Taylor"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cc6ca399cb58ca2b005e675")
}
> db.removeOnlyOneDocumentDemo.insertOne({"FirstName":"David","LastName":"Miller"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cc6ca429cb58ca2b005e676")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.removeOnlyOneDocumentDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5cc6ca2f9cb58ca2b005e674"),
"FirstName" : "John",
"LastName" : "Smith"
}
{
"_id" : ObjectId("5cc6ca399cb58ca2b005e675"),
"FirstName" : "Carol",
"LastName" : "Taylor"
}
{
"_id" : ObjectId("5cc6ca429cb58ca2b005e676"),
"FirstName" : "David",
"LastName" : "Miller"
}以下是仅删除MongoDB中的一个文档的查询。在这里，我们将删除带有“名字”大卫的文档-
> var documentValue = db.removeOnlyOneDocumentDemo.findOne({'FirstName':'David'});
> db.removeOnlyOneDocumentDemo.remove({_id:documentValue._id});
WriteResult({ "nRemoved" : 1 })让我们检查一个文档是否已从集合中删除-
> db.removeOnlyOneDocumentDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5cc6ca2f9cb58ca2b005e674"),
"FirstName" : "John",
"LastName" : "Smith"
}
{
"_id" : ObjectId("5cc6ca399cb58ca2b005e675"),
"FirstName" : "Carol",
"LastName" : "Taylor"
}热门推荐
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