Creating query in MongoDB Java driver

Question

I have a collection with documents that have the following fields:

description
state
field_num

I would like to return a cursor to all the documents that meet the following critiria:

have status "complete"
and field_num greater than 100
and that their description does not contain "abc" pattern?

Is this query correct?

DBObject query = new BasicDBObject("$gte",99)
    .append("status","complete")
    .append("description", new BasicDBObject("$not", ".*abc")))

DBCursor cursor = collection.find("collection name", query, projection)

"is that query correct"? -> execute the query, check the results. — UninformedUser
– UninformedUser, Commented Jan 22, 2018 at 7:09
By the way,$gte is "greater than or equals 99". That is for sure not "greater than 100" — UninformedUser
– UninformedUser, Commented Jan 22, 2018 at 7:10
I tried it, I am getting an error when doing cursor.hasNext(). though I might have a problem in the query. — Ohad
– Ohad, Commented Jan 22, 2018 at 7:11

glytching · Accepted Answer · 2018-01-22 09:38:13Z

This query:

have status "complete"

and field_num greater than 100

and that their description does not contain "abc" pattern?

... can be expressed as follows:

Bson query =
        // where field_num > 100
        new BasicDBObject("field_num", new BasicDBObject("$gte", 100))

        // where status is ' complete'
        .append("status", new BasicDBObject("$eq", "complete"))

        // where description does not contain 'abc' 
        // note: this uses inverse matching since the $not operator
        // is not allowed with the $regex operator
        .append("description", new BasicDBObject("$regex", "^((?!abc).)*$"));

In versions of the Java driver > 3.0 this can also be expressed more simply as:

Bson query= Filters.and(
        Filters.gt("field_num", 100),
        Filters.eq("status", "complete"),
        Filters.regex("description", "^((?!abc).)*$")
);

The query is executed as follows:

MongoClient mongoClient = ...;

MongoCollection<Document> collection = mongoClient.getDatabase("...")
    .getCollection("...");

collection.find(query)

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