如何编写查询以更新嵌入式文档

Question

I new to spring data mongodb,but i am just stuck with,how to write json based query for embedded documents using mongo repository.

My database looks like

"_id" : ObjectId("5565ad670cf25cbd975ab2d9"),
    "_class" : "com.samepinch.domain.metadata.Metadata",
    "preferenceType" : "shopping",
    "subtypes" : [
        {
            "_id" : ObjectId("5565ad670cf25cbd975ab2d2"),
            "subType" : "veg",
            "preferencePoint" : 0
        },
        {
            "_id" : null,
            "subType" : "nonveg",
            "preferencePoint" : 0
        }
    ],
    "createdDate" : ISODate("2015-05-27T11:41:27.357Z"),
    "updatedDate" : ISODate("2015-05-27T11:41:27.357Z")

I want to update subtypes based upon top level document id,i have to update preferencePoint for subtype having id 5565ad670cf25cbd975ab2d2 ,how to write query for this ?

Answer 1

You should use $ projection with $elemMatch query look like :

db.collectionName.update({"_id" : ObjectId("5565ad670cf25cbd975ab2d9"),
"subtypes":{"$elemMatch":{"_id":ObjectId("5565ad670cf25cbd975ab2d2")}}},
{"$set":{"subtypes.$.preferencePoint":1}})

And its equivalent java code as :

BasicDBObject eleMatch = new BasicDBObject();
eleMatch.put("_id", new ObjectId("5565ad670cf25cbd975ab2d2"));
BasicDBObject elemMatchQuery = new BasicDBObject();
elemMatchQuery.put("$elemMatch", eleMatch);
BasicDBObject query = new BasicDBObject();
query.put("_id", new ObjectId("5565ad670cf25cbd975ab2d9"));
query.put("subtypes", elemMatchQuery);
BasicDBObject set = new BasicDBObject();
set.put("subtypes.$.preferencePoint", 1);
BasicDBObject update = new BasicDBObject();
update.put("$set", set);
DBCollection dbcoll = mongoTemplate.getCollection("collectionName");
DBObject object = dbcoll.update(query, update);

Answer 2

from the @Query java doc org.springframework.data. mongodb .repository. Query

Annotation to declare finder queries directly on repository methods. Both attributes allow using a placeholder notation of ?0, ?1 and so on.

Here are all the attributes you can pass to the annotation (below)

From the definition it seems you can only Read, filter for specific fields, perform count(), or delete the domain objects that match your query. I don't see anything regarding updates.

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@Documented
@QueryAnnotation
public @interface Query {

    /**
     * Takes a MongoDB JSON string to define the actual query to be executed. This one will take precendece over the
     * method name then.
     * 
     * @return
     */
    String value() default "";

    /**
     * Defines the fields that should be returned for the given query. Note that only these fields will make it into the
     * domain object returned.
     * 
     * @return
     */
    String fields() default "";

    /**
     * Returns whether the query defined should be executed as count projection.
     * 
     * @since 1.3
     * @return
     */
    boolean count() default false;

    /**
     * Returns whether the query should delete matching documents.
     * 
     * @since 1.5
     * @return
     */
    boolean delete() default false;