MongoDB find()用于递归搜索？
find()与点表示法一起使用以执行递归搜索。首先让我们创建一个包含文档的集合-
> db.findOperationDemo.insertOne({"ClientDetails":[{"ClientId":101,"ClientName":"Chris"},{"ClientId":102,"ClientName":"Robert"}]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd9a118b50a6c6dd317ad99")
}
> db.findOperationDemo.insertOne({"ClientDetails":[{"ClientId":110,"ClientName":"David"},{"ClientId":112,"ClientName":"Mike"}]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd9a12fb50a6c6dd317ad9a")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.findOperationDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5cd9a118b50a6c6dd317ad99"),
"ClientDetails" : [
{
"ClientId" : 101,
"ClientName" : "Chris"
},
{
"ClientId" : 102,
"ClientName" : "Robert"
}
]
}
{
"_id" : ObjectId("5cd9a12fb50a6c6dd317ad9a"),
"ClientDetails" : [
{
"ClientId" : 110,
"ClientName" : "David"
},
{
"ClientId" : 112,
"ClientName" : "Mike"
}
]
}以下是find()使用点表示法实现递归搜索的查询-
> db.findOperationDemo.find({"ClientDetails.ClientId":110});这将产生以下输出-
{ "_id" : ObjectId("5cd9a12fb50a6c6dd317ad9a"), "ClientDetails" : [ { "ClientId" : 110, "ClientName" : "David" }, { "ClientId" : 112, "ClientName" : "Mike" } ] }