MongoDB,使用java同时更新三个文件字段,有时只更新两个字段

Question

//get the collection
DBCollection coll = MongoDBClient.getInstance().getAlarmInfoCollection();

DBObject query = new BasicDBObject();
query.put(aa, "51d2b09f81b8a943f9e825aa");

DBObject update = new BasicDBObject();
DBObject history = new BasicDBObject();
history.put("ishistory", 1);
history.put("acknowledged", 1);
history.put("state", 1);        
update.put("$set", history);
coll.updateMulti(query, update);

使用程序之前更新mongodb中的文档,但有时它可以成功,有时它只更新两个字段(字段,"状态",没有更新),并且propram没有报告任何错误.我的课程有什么错吗？

Answer 1

I've written a unit test to show how the code behaves. This unit test proves that:

1. you should be able to update more than one field at once (i.e. multiple fields can be updated with the $set keyword)
2. updateMulti will update all matching documents

(Note, like all Java MongoDB tests this uses TestNG not JUnit, but it's pretty similar in this case)

@Test
public void shouldUpdateAllMatchingFieldsUsingMultiUpdate() throws UnknownHostException {
    MongoClient mongoClient = new MongoClient();
    DB db = mongoClient.getDB("myDatabase");
    DBCollection coll = db.getCollection("coll");
    coll.drop();

    //Put some test data in the database
    for (int i = 0; i < 5; i++) {
        DBObject value = new BasicDBObject();
        value.put("fieldToQuery", "a");
        value.put("ishistory", 2+i);
        value.put("acknowledged", 3+i);
        value.put("state", 14+i);
        value.put("someOtherArbitraryField", Math.random() * 1000);
        System.out.println(value);
        coll.insert(value);
    }

    DBObject query = new BasicDBObject("fieldToQuery", "a");

    DBObject history = new BasicDBObject().append("ishistory", 1)
                                          .append("acknowledged", 1)
                                          .append("state", 1);

    DBObject update = new BasicDBObject("$set", history);

    //This syntax for update means that all three fields will be set to the new given value
    Assert.assertEquals(update.toString(), "{ \"$set\" : { \"ishistory\" : 1 , \"acknowledged\" : 1 , \"state\" : 1}}");

    //Do the update, updating every document that matches the query
    coll.updateMulti(query, update);

    //find The new values
    DBCursor updatedDocuments = coll.find(query);
    for (DBObject updatedDocument : updatedDocuments) {
        Assert.assertEquals(updatedDocument.get("ishistory"), 1);
        Assert.assertEquals(updatedDocument.get("acknowledged"), 1);
        Assert.assertEquals(updatedDocument.get("state"), 1);
        System.out.println(updatedDocument);
    }
}

This test passes. For an example run, the data in the database is:

{ "fieldToQuery" : "a" , "ishistory" : 2 , "acknowledged" : 3 , "state" : 14 , "someOtherArbitraryField" : 700.7831275035031}
{ "fieldToQuery" : "a" , "ishistory" : 3 , "acknowledged" : 4 , "state" : 15 , "someOtherArbitraryField" : 72.65538582882736}
{ "fieldToQuery" : "a" , "ishistory" : 4 , "acknowledged" : 5 , "state" : 16 , "someOtherArbitraryField" : 980.0065367659304}
{ "fieldToQuery" : "a" , "ishistory" : 5 , "acknowledged" : 6 , "state" : 17 , "someOtherArbitraryField" : 91.58266286854722}
{ "fieldToQuery" : "a" , "ishistory" : 6 , "acknowledged" : 7 , "state" : 18 , "someOtherArbitraryField" : 448.19176202797115}

At the end of the test, after updateMulti is called with the $set operator, the documents in the database are:

{ "fieldToQuery" : "a" , "ishistory" : 1 , "acknowledged" : 1 , "state" : 1 , "someOtherArbitraryField" : 700.7831275035031}
{ "fieldToQuery" : "a" , "ishistory" : 1 , "acknowledged" : 1 , "state" : 1 , "someOtherArbitraryField" : 72.65538582882736}
{ "fieldToQuery" : "a" , "ishistory" : 1 , "acknowledged" : 1 , "state" : 1 , "someOtherArbitraryField" : 980.0065367659304}
{ "fieldToQuery" : "a" , "ishistory" : 1 , "acknowledged" : 1 , "state" : 1 , "someOtherArbitraryField" : 91.58266286854722}
{ "fieldToQuery" : "a" , "ishistory" : 1 , "acknowledged" : 1 , "state" : 1 , "someOtherArbitraryField" : 448.19176202797115}

So the update has worked, setting the three fields to 1 for all matching documents, not touching any of the other data on the document.

It might be worth noting that my syntax for setting query, update and history is a little more readable and bit shorter, although it should be doing the same thing as the code in the original question:

DBObject query = new BasicDBObject("fieldToQuery", "a");

DBObject history = new BasicDBObject().append("ishistory", 1)
                                      .append("acknowledged", 1)
                                      .append("state", 1);

DBObject update = new BasicDBObject("$set", history);

Am I correct in assuming that you want all records that match your query to be updated with the given values? Hence your use of updateMulti?