このチュートリアルでは、Java MongoDB API `collection.update（）`を使用してドキュメントを更新する方法を説明します。

テストデータ

以下のデータ/文書が挿入されていると仮定します。 

{
    "hosting" : "hostA",
    "type" : "vps",
    "clients" : 1000
},
{
    "hosting" : "hostB",
    "type" : "dedicated server",
    "clients" : 100
},
{
    "hosting" : "hostC",
    "type" : "vps",
    "clients" : 900
}

{ "__id" : { "$oid" : "id"} , "hosting" : "hostA" , "type" : "vps" , "clients" : 1000}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostB" , "type" : "dedicated server" , "clients" : 100}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostC" , "type" : "vps" , "clients" : 900}

1. $ setを指定したDBCollection.update（）

hosting = ‘hostB’のところで文書を検索し、クライアントの値を100から110に更新します。 

    BasicDBObject newDocument = new BasicDBObject();
    newDocument.put("clients", 110);

    BasicDBObject searchQuery = new BasicDBObject().append("hosting", "hostB");

    collection.update(searchQuery, newDocument);


出力
 

{ "__id" : { "$oid" : "id"} , "hosting" : "hostA" , "type" : "vps" , "clients" : 1000}
{ "__id" : { "$oid" : "id"} , "clients" : 110}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostC" , "type" : "vps" , "clients" : 900}

特定の値だけを更新するには、

$ set

update修飾子を使います。 

    BasicDBObject newDocument = new BasicDBObject();
    newDocument.append("$set", new BasicDBObject().append("clients", 110));

    BasicDBObject searchQuery = new BasicDBObject().append("hosting", "hostB");

    collection.update(searchQuery, newDocument);


出力
 

{ "__id" : { "$oid" : "id"} , "hosting" : "hostA" , "type" : "vps" , "clients" : 1000}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostB" , "type" : "dedicated server" , "clients" : 110}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostC" , "type" : "vps" , "clients" : 900}

  • Note ** + MongoDBチームは

    DBCollection.replace（）`という名前の別の新しいAPIを作成する必要があります。多くの初心者はこの `DBCollection.update（）

    APIに閉じ込められ、誤ってドキュメント全体を置き換えます。再び、特定の値を更新するには `$ set`を使います。

2. $ incを指定したDBCollection.update（）

この例では、特定の値を増やすために `$ inc`修飾子を使用しています。 hosting = ‘hostB’の文書を検索し、値を100から199、（100 99）= 199に増やして ‘clients’値を更新します。 

    BasicDBObject newDocument =
        new BasicDBObject().append("$inc",
        new BasicDBObject().append("total clients", 99));

    collection.update(new BasicDBObject().append("hosting", "hostB"), newDocument);


出力
 

{ "__id" : { "$oid" : "id"} , "hosting" : "hostA" , "type" : "vps" , "clients" : 1000}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostB" , "type" : "dedicated server" , "clients" : 199}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostC" , "type" : "vps" , "clients" : 900}

3. DBCollection.update（）とmulti

この例は、一致したドキュメントのセットを更新するための `multi`パラメータの使用を示しています。 type = ‘vps’の文書を検索し、一致するすべての文書の ‘clients’値を888に更新します。 

    BasicDBObject updateQuery = new BasicDBObject();
    updateQuery.append("$set",
        new BasicDBObject().append("clients", "888"));

    BasicDBObject searchQuery = new BasicDBObject();
    searchQuery.append("type", "vps");

    collection.updateMulti(searchQuery, updateQuery);

   //below statement set multi to true.
   //collection.update(searchQuery, updateQuery, false, true);


出力
 

{ "__id" : { "$oid" : "id"} , "hosting" : "hostA" , "clients" : "888" , "type" : "vps"}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostB" , "type" : "dedicated server" , "clients" : 100}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostC" , "clients" : "888" , "type" : "vps"}

  • 注意** `multi`を指定せずにupdateをtrueに設定した場合。 

    BasicDBObject updateQuery = new BasicDBObject();
    updateQuery.append("$set",
        new BasicDBObject().append("clients", "888"));

    BasicDBObject searchQuery = new BasicDBObject();
    searchQuery.append("type", "vps");

    collection.update(searchQuery, updateQuery);

最初に一致した文書だけが更新されていることに気付きます。 

{"__id":{ "$oid" : "x"} , "hosting" : "hostA" , "clients" : "888" , "type" : "vps"}
{"__id":{ "$oid" : "x"} , "hosting" : "hostB" , "type" : "dedicated server" , "clients" : 100}
{"__id":{ "$oid" : "x"} , "hosting" : "hostC" , "type" : "vps" , "clients" : 900}

一致するドキュメントのセットを更新するには、 “multi”をtrueに設定する必要があります。

4.完全な例

上記のコードスニペットを組み合わせて完全な例。 

package com.mkyong.core;

import java.net.UnknownHostException;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.Mongo;
import com.mongodb.MongoException;
/** **
 **  Java MongoDB update document
 **
 **  @author mkyong
 **
 ** /
public class UpdateApp {

    public static void printAllDocuments(DBCollection collection) {
        DBCursor cursor = collection.find();
        while (cursor.hasNext()) {
            System.out.println(cursor.next());
        }
    }

    public static void removeAllDocuments(DBCollection collection) {
        collection.remove(new BasicDBObject());
    }

    public static void insertDummyDocuments(DBCollection collection) {
        BasicDBObject document = new BasicDBObject();
        document.put("hosting", "hostA");
        document.put("type", "vps");
        document.put("clients", 1000);

        BasicDBObject document2 = new BasicDBObject();
        document2.put("hosting", "hostB");
        document2.put("type", "dedicated server");
        document2.put("clients", 100);

        BasicDBObject document3 = new BasicDBObject();
        document3.put("hosting", "hostC");
        document3.put("type", "vps");
        document3.put("clients", 900);

        collection.insert(document);
        collection.insert(document2);
        collection.insert(document3);
    }

    public static void main(String[]args) {

    try {

      Mongo mongo = new Mongo("localhost", 27017);
      DB db = mongo.getDB("yourdb");

     //get a single collection
      DBCollection collection = db.getCollection("dummyColl");

      System.out.println("Testing 1...no $set");

      insertDummyDocuments(collection);

     //find hosting = hostB, and update the clients to 110
      BasicDBObject newDocument = new BasicDBObject();
      newDocument.put("clients", 110);

      BasicDBObject searchQuery = new BasicDBObject().append("hosting", "hostB");

      collection.update(searchQuery, newDocument);

      printAllDocuments(collection);
      removeAllDocuments(collection);

      System.out.println("\nTesting 1...with $set");

      insertDummyDocuments(collection);

      BasicDBObject updateDocument = new BasicDBObject();
      updateDocument.append("$set", new BasicDBObject().append("clients", 110));

      BasicDBObject searchQuery2 = new BasicDBObject().append("hosting", "hostB");

      collection.update(searchQuery2, updateDocument);

      printAllDocuments(collection);
      removeAllDocuments(collection);

      System.out.println("\nTesting 2... with $inc");
      insertDummyDocuments(collection);
     //find hosting = hostB and increase it's "clients" value by 99
      BasicDBObject newDocument2 = new BasicDBObject().append("$inc",
        new BasicDBObject().append("clients", 99));

      collection.update(new BasicDBObject().append("hosting", "hostB"), newDocument2);

      printAllDocuments(collection);
      removeAllDocuments(collection);

      System.out.println("\nTesting 3... with $multi");

      insertDummyDocuments(collection);
     //find type = vps , update all matched documents , clients value to 888
      BasicDBObject updateQuery = new BasicDBObject();
      updateQuery.append("$set", new BasicDBObject().append("clients", "888"));

      BasicDBObject searchQuery3 = new BasicDBObject();
      searchQuery3.append("type", "vps");

      collection.updateMulti(searchQuery3, updateQuery);
     //collection.update(searchQuery3, updateQuery, false, true);

      printAllDocuments(collection);
      removeAllDocuments(collection);

      System.out.println("Done");

    } catch (UnknownHostException e) {
        e.printStackTrace();
    } catch (MongoException e) {
        e.printStackTrace();
    }

    }
}

出力 

Testing 1...no $set
{ "__id" : { "$oid" : "id"} , "hosting" : "hostA" , "type" : "vps" , "clients" : 1000}
{ "__id" : { "$oid" : "id"} , "clients" : 110}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostC" , "type" : "vps" , "clients" : 900}

Testing 1...with $set
{ "__id" : { "$oid" : "id"} , "hosting" : "hostA" , "type" : "vps" , "clients" : 1000}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostB" , "type" : "dedicated server" , "clients" : 110}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostC" , "type" : "vps" , "clients" : 900}

Testing 2... with $inc
{ "__id" : { "$oid" : "id"} , "hosting" : "hostA" , "type" : "vps" , "clients" : 1000}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostB" , "type" : "dedicated server" , "clients" : 199}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostC" , "type" : "vps" , "clients" : 900}

Testing 3... with $multi
{ "__id" : { "$oid" : "id"} , "hosting" : "hostB" , "type" : "dedicated server" , "clients" : 100}
{ "__id" : { "$oid" : "id"} , "hosting" : "hostC" , "type" : "vps" , "clients" : 900}
{ "__id" : { "$oid" : "id"} , "clients" : "888" , "hosting" : "hostA" , "type" : "vps"}
Done

参考文献


  1. 更新の仕方

MongoDBで]。

http://docs.mongodb.org/manual/reference/operator/set/#op

.

S

set[$set

更新修飾子]。

http://docs.mongodb.org/manual/reference/operator/inc/#op

.

S

inc[$inc

更新修飾子]。

http://api.mongodb.org/java/current/com/mongodb/DBCollection.html

[Java

MongoDB API、DBCollection JavaDoc]


mongodb


update