CODEWITHSUNDEEP
mongodbmongodb-querymorphianosql
Edy Bourne
Edy Bourne

Reputation: 6187

MongoDB / Morphia - Delete object not behaving properly, what did I miss?

I have query for deletion like so:

Query<E> query = datastore.createQuery(entityClass);
query.field(fieldName).equals(fieldValue);
return datastore.findAndDelete(query);

So the intent is to select an object based on an unique field and have it deleted. I have four objects in the collection, each with a different value for the field I'm querying by. But when I perform the findAndDelete a random object is deleted returned, not the one matching the criteria.

I execute this over and over and each time another random object is returned, until all are deleted and then it returns null.

I'm essentially executing this:

Query<Entity> query = datastore.createQuery(Entity.class);
query.field("uniqueHash").equals("SDFSDGRTGEFQDFRYDGSWE");
return datastore.findAndDelete(query);

And when I debug I see that all objects in the collections actually have different values for the uniqueHash field

What am I missing?? Am I not building this query correctly?

**UPDATE: ** Here is the complete data before and after the delete operation:

> db.CustomObject.find().pretty()
{
        "_id" : ObjectId("54a590546c66e6672cfff53a"),
        "className" : "com.test.CustomObject",
        "tokenHash" : "SG6o3mXOOBfGHYlhA2S2p52O1/GXOUZvF6kY5X3ZyvA="
}
{
        "_id" : ObjectId("54a590546c66e6672cfff53b"),
        "className" : "com.test.CustomObject",
        "tokenHash" : "RotU72A4E9Oh8qC+cCX4Y+MdIShuuaDX03jQQXZVG34="
}
{
        "_id" : ObjectId("54a590546c66e6672cfff53c"),
        "className" : "com.test.CustomObject",
        "tokenHash" : "sYLKPRlddqc3I+ORVwCzYjzeU+ErBveQNvHYYyCsi7o="
}
{
        "_id" : ObjectId("54a590546c66e6672cfff53d"),
        "className" : "com.test.CustomObject",
        "tokenHash" : "eVltEP/ptPqw6WrMDCCzd+rcoVrShcMr9fF3CENLj8Q="
}

Then I execute:

Query<CustomObject> query = datastore.createQuery(CustomObject.class);
query.field("tokenHash").equals("RotU72A4E9Oh8qC+cCX4Y+MdIShuuaDX03jQQXZVG34=");
return datastore.findAndDelete(query);

And the result is that an object was deleted, but not the one I was hoping for:

> db.CustomObject.find().pretty()
{
        "_id" : ObjectId("54a590546c66e6672cfff53b"),
        "className" : "com.test.CustomObject",
        "tokenHash" : "RotU72A4E9Oh8qC+cCX4Y+MdIShuuaDX03jQQXZVG34="
}
{
        "_id" : ObjectId("54a590546c66e6672cfff53c"),
        "className" : "com.test.CustomObject",
        "tokenHash" : "sYLKPRlddqc3I+ORVwCzYjzeU+ErBveQNvHYYyCsi7o="
}
{
        "_id" : ObjectId("54a590546c66e6672cfff53d"),
        "className" : "com.test.CustomObject",
        "tokenHash" : "eVltEP/ptPqw6WrMDCCzd+rcoVrShcMr9fF3CENLj8Q="
}

Thanks!

Upvotes: 2

Views: 2374

Answers (1)

BatScream
BatScream

Reputation: 19700

You need to use the Field class' equal method instead of the equals method of the Object class.

query.field("tokenHash").equal("RotU72A4E9Oh8qC+cCX4Y+MdIShuuaDX03jQQXZVG34=");

equals is a method in the Object class used for comparing the value in two Objects. It returns just true or false. Hence the below statement

query.field("tokenHash").equals("RotU72A4E9Oh8qC+cCX4Y+MdIShuuaDX03jQQXZVG34=");

Would return false, without actually building an query object which the equal method of the Field class does.

Upvotes: 2

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