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法學如何在 MongoDB 中使用自定義欄位對帶分頁的索引和排序進行索引和排序？
首先，讓我們使用文件建立一個集合 −
> db.demo373.createIndex({"Name":1,"CountryName":1});
{
"createdCollectionAutomatically" : true,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
> db.demo373.insertOne({"Name":"Chris","Age":22,"CountryName":"US"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e59ffde2ae06a1609a00aff")
}
> db.demo373.insertOne({"Name":"David","Age":21,"CountryName":"AUS"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e59ffe82ae06a1609a00b00")
}
> db.demo373.insertOne({"Name":"Bob","Age":23,"CountryName":"UK"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e59fff42ae06a1609a00b01")
}
> db.demo373.insertOne({"Name":"John","Age":21,"CountryName":"US"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e59ffff2ae06a1609a00b02")
}
> db.demo373.insertOne({"Name":"Carol","Age":23,"CountryName":"AUS"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e5a00082ae06a1609a00b03")
}藉助 find() 方法從集合中顯示所有文件 −
> db.demo373.find();
這將生成以下輸出 −
{ "_id" : ObjectId("5e59ffde2ae06a1609a00aff"), "Name" : "Chris", "Age" : 22, "CountryName" : "US" }
{ "_id" : ObjectId("5e59ffe82ae06a1609a00b00"), "Name" : "David", "Age" : 21, "CountryName" : "AUS" }
{ "_id" : ObjectId("5e59fff42ae06a1609a00b01"), "Name" : "Bob", "Age" : 23, "CountryName" : "UK" }
{ "_id" : ObjectId("5e59ffff2ae06a1609a00b02"), "Name" : "John", "Age" : 21, "CountryName" : "US" }
{ "_id" : ObjectId("5e5a00082ae06a1609a00b03"), "Name" : "Carol", "Age" : 23, "CountryName" : "AUS" }以下是 MongoDB 中使用分頁實現索引和排序的查詢 −
> db.demo373.find().sort({"Name":1, "Age":1}).limit(4).skip(2);這將生成以下輸出 −
{ "_id" : ObjectId("5e59ffde2ae06a1609a00aff"), "Name" : "Chris", "Age" : 22, "CountryName" : "US" }
{ "_id" : ObjectId("5e59ffe82ae06a1609a00b00"), "Name" : "David", "Age" : 21, "CountryName" : "AUS" }
{ "_id" : ObjectId("5e59ffff2ae06a1609a00b02"), "Name" : "John", "Age" : 21, "CountryName" : "US" }
更新於： 02-Apr-2020
339 次瀏覽
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