Find documents where field is (less than) using lt and lte operator In MongoDb in java




In this mongoDB tutorial we will write java programs to FIND documents where field is (less than) using lt and lte operator in Collection In MongoDb in java.

Contents of page >
  • 1) Program to Query Document From Collection In MongoDb in java using lt and lte Operators >
    • 1.1) Program to Query Document From Collection In MongoDb in java using lt (less than) Operator >
    • 1.2) Program to Query Document From Collection In MongoDb in java using lte (less than equal) Operator >

1) Program to Query Document From Collection In MongoDb in java using lt and lte Operators >
1.1) Program to Query Document From Collection In MongoDb in java using lt (less than) Operator >
FIND documents where id < 2
package queryDocumentFromCollectionInMongoDb;
/**
* Write a program to Query Document From Collection In MongoDb in java using Lt And Lte Operator
*/
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.MongoClient;
import com.mongodb.MongoClientURI;
import com.mongodb.WriteResult;
public class QueryDocumentFromCollectionInMongoDb5_usingLtAndLteOperator {
   public static void main(String[] args) {
          /* Connect to MongoDB */
          MongoClient mongoClient =
                       new MongoClient(new MongoClientURI("mongodb://localhost:27017"));
         
          /* Connect to DATABASE */
          //If in case database doesn't exists, it will be created at runtime
          DB db = mongoClient.getDB("mydb");
                      
          /* Get the COLLECTION (TABLE) */
          //If in case collection (Table) doesn't exists, it will be created at runtime
          DBCollection dbCollection = db.getCollection("Employee");
          /*If collection already exists, you may remove everything
          from collection for perfect OUTPUT of program*/
          dbCollection.remove(new BasicDBObject()); //Not Mandatory
                      
         
          /* create a BasicDBObject1 (document /record) */
          BasicDBObject basicDBObject1 = new BasicDBObject();
          basicDBObject1.put("id", 1);
          basicDBObject1.put("name", "Ankit");
         
          /* Insert document1/record1 in COLLECTION in MongoDB */
          System.out.println("Insert document1");
          dbCollection.insert(basicDBObject1);
         
          /* create a BasicDBObject2 (document /record) */
          BasicDBObject basicDBObject2 = new BasicDBObject();
          basicDBObject2.put("id", 2);
          basicDBObject2.put("name", "Sam");
         
          /* Insert document2 in collection in MongoDB */
          System.out.println("Insert document2");
          dbCollection.insert(basicDBObject2);        
          /* create a BasicDBObject3 (document /record) */
          BasicDBObject basicDBObject3 = new BasicDBObject();
          basicDBObject3.put("id", 3);
          basicDBObject3.put("name", "Neh");
         
          /* Insert document3 in collection in MongoDB */
          System.out.println("Insert document3");
          dbCollection.insert(basicDBObject3);        
          /* Display documents of collection before QUERING DOCUMENTs in MongoDB */
          System.out.println("\nDisplay collection "
                       + "before QUERING collection in MongoDB");
          DBCursor cursor0 = dbCollection.find();
          while (cursor0.hasNext()) {
                 System.out.println(cursor0.next());
          }
         
          /** At this stage dbCollection looks like this >
                { "_id" : { "$oid" : "58559179ad8dc831e8df7a3e"} , "id" : 1 , "name" : "Ankit"}
                { "_id" : { "$oid" : "58559179ad8dc831e8df7a3f"} , "id" : 2 , "name" : "Sam"}
                { "_id" : { "$oid" : "58559179ad8dc831e8df7a40"} , "id" : 3 , "name" : "Neh"}
          */
         
         
          /** Now, let's FIND the documents from collection in MongoDB */
          /** FIND documents where id < 2 */
          BasicDBObject basicDBObject_SearchCondition = new BasicDBObject();
                                         //$lt operator is for LESS THAN
                                         //Pass > $lt as key > and > 2 as value
          basicDBObject_SearchCondition.put("id",
                       new BasicDBObject("$lt", 2));
          /** Execute FIND/SEARCH query - To FIND DOCUMENT in MongoDB */
          //find method Select documents in collection and returns cursor to the selected documents.
          System.out.println("\nExecute FIND query where id < 2 ");
          DBCursor cursor = dbCollection.find(basicDBObject_SearchCondition);
         
          /* Display documents of collection after QUERING collection in MongoDB */
          System.out.println("\nDisplay documents of collection "
                       + "after QUERING collection in MongoDB ");
          while (cursor.hasNext()) {
                 System.out.println(cursor.next());
          }
          /** At this stage dbCollection looks like this >
                { "_id" : { "$oid" : "58559179ad8dc831e8df7a3e"} , "id" : 1 , "name" : "Ankit"}
          */
         
   }
}
/* OUTPUT
Insert document1
Insert document2
Insert document3
Display collection before QUERING collection in MongoDB
{ "_id" : { "$oid" : "58559179ad8dc831e8df7a3e"} , "id" : 1 , "name" : "Ankit"}
{ "_id" : { "$oid" : "58559179ad8dc831e8df7a3f"} , "id" : 2 , "name" : "Sam"}
{ "_id" : { "$oid" : "58559179ad8dc831e8df7a40"} , "id" : 3 , "name" : "Neh"}
Execute FIND query where id < 2
Display documents of collection after QUERING collection in MongoDB
{ "_id" : { "$oid" : "58559179ad8dc831e8df7a3e"} , "id" : 1 , "name" : "Ankit"}
*/


1.2) Program to Query Document From Collection In MongoDb in java using lte (less than equal) Operator >
FIND documents where id <= 2
FIND documents where id <= 2 From this collection
{ "_id" : { "$oid" : "58559179ad8dc831e8df7a3e"} , "id" : 1 , "name" : "Ankit"}
{ "_id" : { "$oid" : "58559179ad8dc831e8df7a3f"} , "id" : 2 , "name" : "Sam"}
{ "_id" : { "$oid" : "58559179ad8dc831e8df7a40"} , "id" : 3 , "name" : "Neh"}
BasicDBObject basicDBObject_SearchCondition = new BasicDBObject();
                                     //$lte operator is for LESS THAN EQUAL
                                      //Pass > $lte as key - and - 2 as value
basicDBObject_SearchCondition.put("id", new BasicDBObject("$lte", 2));
Result
{ "_id" : { "$oid" : "58559179ad8dc831e8df7a3e"} , "id" : 1 , "name" : "Ankit"}
{ "_id" : { "$oid" : "58559179ad8dc831e8df7a3f"} , "id" : 2 , "name" : "Sam"}


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