使用findOne()下的ObjectId来获取MongoDB中的特定记录？
首先让我们创建一个包含文档的集合-
> db.findOneWorkingDemo.insertOne({"ClientId":1,"ClientName":"Larry","ClientAge":26});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd7c1716d78f205348bc64d")
}
> db.findOneWorkingDemo.insertOne({"ClientId":2,"ClientName":"Chris","ClientAge":28});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd7c17d6d78f205348bc64e")
}
> db.findOneWorkingDemo.insertOne({"ClientId":3,"ClientName":"Robert","ClientAge":34});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd7c1896d78f205348bc64f")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.findOneWorkingDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5cd7c1716d78f205348bc64d"),
"ClientId" : 1,
"ClientName" : "Larry",
"ClientAge" : 26
}
{
"_id" : ObjectId("5cd7c17d6d78f205348bc64e"),
"ClientId" : 2,
"ClientName" : "Chris",
"ClientAge" : 28
}
{
"_id" : ObjectId("5cd7c1896d78f205348bc64f"),
"ClientId" : 3,
"ClientName" : "Robert",
"ClientAge" : 34
}以下是要findOne()使用ObjectId实现的查询-
> db.findOneWorkingDemo.findOne({"_id":ObjectId("5cd7c17d6d78f205348bc64e")});这将产生以下输出-
{
"_id" : ObjectId("5cd7c17d6d78f205348bc64e"),
"ClientId" : 2,
"ClientName" : "Chris",
"ClientAge" : 28
}