MongoDB 中的数组索引或索引内部项以获取值
mongodbdatabasebig data analytics更新于 2026/1/9 17:52:17
首先，让我们创建一个包含文档的集合，并使用 ensureIndex() 创建索引 −
> db.demo323.insertOne({"details":{"Name":"Chris","Age":34}});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e51157af8647eb59e56206e")
}
> db.demo323.insertOne({"details":{"Name":"David","Age":31}});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e511581f8647eb59e56206f")
}
> db.demo323.insertOne({"details":{"Name":"Bob","Age":28}});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e511589f8647eb59e562070")
}
> db.demo323.ensureIndex({"details.Name":1});
{
"createdCollectionAutomatically" : false,
"numIndexesBefore" : 2,
"numIndexesAfter" : 3,
"ok" : 1
}
使用 find() 方法显示集合中的所有文档 −
> db.demo323.find();
将产生以下输出 −
{ "_id" : ObjectId("5e51157af8647eb59e56206e"), "details" : { "Name" : "Chris", "Age" : 34 } }
{ "_id" : ObjectId("5e511581f8647eb59e56206f"), "details" : { "Name" : "David", "Age" : 31 } }
{ "_id" : ObjectId("5e511589f8647eb59e562070"), "details" : { "Name" : "Bob", "Age" : 28 } }
以下是从数组中查找值的查询 −
> db.demo323.find({"details.Name":"Bob"});
这将产生以下输出 −
{ "_id" : ObjectId("5e511589f8647eb59e562070"), "details" : { "Name" : "Bob", "Age" : 28 } }
