索引大型文本字段以使MongoDB中的查询更快
要为大文本字段建立索引，请ensureIndex()与$regex一起使用以进行文本搜索。让我们创建一个包含文档的集合-
> db.demo46.ensureIndex({"Name":1});
{
"createdCollectionAutomatically" : true,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
> db.demo46.insertOne({"Name":"John Smith"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e267004cfb11e5c34d898ed")
}
> db.demo46.insertOne({"Name":"John Doe"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e267009cfb11e5c34d898ee")
}
> db.demo46.insertOne({"Name":"Chris Brown"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e267011cfb11e5c34d898ef")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo46.find();
这将产生以下输出-
{ "_id" : ObjectId("5e267004cfb11e5c34d898ed"), "Name" : "John Smith" }
{ "_id" : ObjectId("5e267009cfb11e5c34d898ee"), "Name" : "John Doe" }
{ "_id" : ObjectId("5e267011cfb11e5c34d898ef"), "Name" : "Chris Brown" }以下是索引大文本字段以使查询更快的查询-
> db.demo46.find({ Name: { $regex:/^John/}});这将产生以下输出-
{ "_id" : ObjectId("5e267009cfb11e5c34d898ee"), "Name" : "John Doe" }
{ "_id" : ObjectId("5e267004cfb11e5c34d898ed"), "Name" : "John Smith" }