Querying with Conditions

The examples in this section query a document store and return documents that have specific conditions.

For more information about how to specify query conditions in OJAI, see Query Conditions in OJAI Applications.

Note: You can improve the performance of queries with conditions by using secondary indexes. See Queries that Benefit from Secondary Indexes for more details.

Java - OJAI `QueryCondition` Object

The following example shows how to return all documents from a store where address.zipCode equals 95196, using the Query.where method. It uses an OJAI QueryCondition to specify the condition.

/**
 * Copyright (c) 2017 MapR, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */
package com.mapr.ojai.examples;

import org.ojai.Document;
import org.ojai.DocumentStream;
import org.ojai.store.Connection;
import org.ojai.store.DocumentStore;
import org.ojai.store.DriverManager;
import org.ojai.store.Query;
import org.ojai.store.QueryCondition.Op;

public class OJAI_007_FindQueryWithCondition {

  public static void main(final String[] args) {

    System.out.println("==== Start Application ===");

    // Create an OJAI connection to MapR cluster
    final Connection connection = DriverManager.getConnection("ojai:mapr:");

    // Get an instance of OJAI DocumentStore
    final DocumentStore store = connection.getStore("/demo_table");

    // Build an OJAI query with QueryCondition
    final Query query = connection.newQuery()
        .where(
            connection.newCondition()                   //
                .is("address.zipCode", Op.EQUAL, 95196)   // Build an OJAI QueryCondition
                .build())                                 //
        .build();

    // fetch all OJAI Documents from this store
    final DocumentStream stream = store.find(query);

    for (final Document userDocument : stream) {
      // Print the OJAI Document
      System.out.println(userDocument.asJsonString());
    }

    // Close this instance of OJAI DocumentStore
    store.close();

    // close the OJAI connection and release any resources held by the connection
    connection.close();

    System.out.println("==== End Application ===");
  }

}

Java - OJAI Query Condition in JSON Format

The following example shows how to return all documents from a store where address.zipCode equals 95196, using the Query.where method. It specifies the query condition using a JSON string.

/**
 * Copyright (c) 2017 MapR, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */
package com.mapr.ojai.examples;

import org.ojai.Document;
import org.ojai.DocumentStream;
import org.ojai.store.Connection;
import org.ojai.store.DocumentStore;
import org.ojai.store.DriverManager;
import org.ojai.store.Query;

public class OJAI_008_FindQueryWithConditionJson {

  public static void main(final String[] args) {

    System.out.println("==== Start Application ===");

    // Create an OJAI connection to MapR cluster
    final Connection connection = DriverManager.getConnection("ojai:mapr:");

    // Get an instance of OJAI DocumentStore
    final DocumentStore store = connection.getStore("/demo_table");

    // Build an OJAI query with the condition specified as a JSON string
    final Query query = connection.newQuery()
        .where("{\"$eq\": {\"address.zipCode\": 95196}}")
        .build();

    // fetch all OJAI Documents from this store
    final DocumentStream stream = store.find(query);

    for (final Document userDocument : stream) {
      // Print the OJAI Document
      System.out.println(userDocument.asJsonString());
    }

    // Close this instance of OJAI DocumentStore
    store.close();

    // close the OJAI connection and release any resources held by the connection
    connection.close();

    System.out.println("==== End Application ===");
  }

}

Node.js - OJAI Query Condition in JSON Format

The following example uses an OJAI query condition specified in JSON format to return all documents from a store where address.zipCode equals 95196.

/*
 * Copyright (c) 2018 MapR, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

const { ConnectionManager } = require('node-maprdb');

const connectionString = 'localhost:5678?' +
  'auth=basic;' +
  'user=mapr;' +
  'password=mapr;' +
  'ssl=true;' +
  'sslCA=/opt/mapr/conf/ssl_truststore.pem;' +
  'sslTargetNameOverride=node1.mapr.com';

let connection;

// Create a connection to data access server
ConnectionManager.getConnection(connectionString)
  .then((conn) => {
    connection = conn;
    // Get a store
    return connection.getStore('/demo_table');
  })
  .then((store) => {
    // Create an OJAI query
    const query = {"$where": {"$eq": { 'address.zipCode': 95196 }}};
    // fetch OJAI Documents by query
    return store.find(query);
  })
  .then((queryResult) => {
    queryResult.on('data', (document) => {
      // Print OJAI Documents from document stream
      console.log(document);
    });
    queryResult.on('end', () => {
      // close the OJAI connection
      connection.close();
    });
  });

Python - OJAI `QueryCondition` Object

The following example shows how to return all documents from a store where address.zipCode equals 95196, using the Query.where method. It uses an OJAI QueryCondition to specify the condition.

from mapr.ojai.ojai_query.QueryOp import QueryOp
from mapr.ojai.storage.ConnectionFactory import ConnectionFactory

# Create a connection to data access server
connection_str = "localhost:5678?auth=basic;user=mapr;password=mapr;" \
          "ssl=true;" \
          "sslCA=/opt/mapr/conf/ssl_truststore.pem;" \
          "sslTargetNameOverride=node1.mapr.com"
connection = ConnectionFactory.get_connection(connection_str=connection_str)

# Get a store and assign it as a DocumentStore object
store = connection.get_store('/demo_table')

# Create an OJAI query
query = connection.new_query()\
    .where(connection.new_condition()
           .is_('address.zipCode', QueryOp.EQUAL, 95196)
           .close()
           .build())\
    .build()

# fetch the OJAI Documents by query
query_result = store.find(query)

# Print OJAI Documents from document stream
for doc in query_result:
    print(doc)

# close the OJAI connection
connection.close()

Python - OJAI Query Condition in JSON Format

The following example uses an OJAI query condition specified in JSON format to return all documents from a store where address.zipCode equals 95196.

from mapr.ojai.storage.ConnectionFactory import ConnectionFactory

# Create a connection to data access server
connection_str = "localhost:5678?auth=basic;user=mapr;password=mapr;" \
          "ssl=true;" \
          "sslCA=/opt/mapr/conf/ssl_truststore.pem;" \
          "sslTargetNameOverride=node1.mapr.com"
connection = ConnectionFactory.get_connection(connection_str=connection_str)

# Get a store and assign it as a DocumentStore object
store = connection.get_store('/demo_table')

# Create an OJAI query
query = {"$where": {"$eq": {"address.zipCode": 95196}}}

# options for find request
options = {
    'ojai.mapr.query.result-as-document': True
    }

# fetch OJAI Documents by query
query_result = store.find(query, options=options)

# Print OJAI Documents from document stream
for doc in query_result:
    print(doc.as_dictionary())

# close the OJAI connection
connection.close()

dbshell

The following two dbshell commands are equivalent to the code examples. See dbshell find or findbyid for more details about the syntax dbshell provides.

# mapr dbshell
maprdb root:> find /demo_table --q {"$where":{"$eq":{"address.zipCode":95196}}}

maprdb root:> find /demo_table --where {"$eq":{"address.zipCode":95196}}

C# - OJAI `QueryCondition` Object

The following example shows how to return all documents from a store where address.zipCode equals 95196, using the Query.Where method. It uses an OJAI QueryCondition to specify the condition.

using System;
using MapRDB.Driver;
using MapRDB.Driver.Ojai;

public class FindQueryWithCondition
{
	public async void FindQueryWithCondition()
	{
        // Create a connection to data access server
        var connectionStr = $"localhost:5678?auth=basic;" +
            $"user=mapr;" +
            $"password=mapr;" +
            $"ssl=true;" +
            $"sslCA=/opt/mapr/conf/ssl_truststore.pem;" +
            $"sslTargetNameOverride=node1.mapr.com";
        var connection = ConnectionFactory.CreateConnection(connectionStr);

        // Get a store and assign it as a DocumentStore object
        var store = connection.GetStore("/demo_table");

        //Create an OJAI query
        var query = connection
            .NewQuery()
                .Where(connection
                        .NewQueryCondition()
                            .Is("address.zipCode", QueryOp.EQUAL, 95196)
                            .Close()
                        .Build())
                 .Build();

        // Fetch the OJAI Documents by query
        var queryResult = store.Find(query);

        var documentStream = await queryResult.GetDocumentAsyncStream().GetAllDocuments();
        // Print OJAI Documents from document stream
        foreach (var document in documentStream)
        {
            Console.WriteLine(document);
        }

        // Close the OJAI connection
        connection.Close();
    }
}

C# - OJAI Query Condition in JSON Format

The following example uses an OJAI query condition specified in JSON format to return all documents from a store where address.zipCode equals 95196.

using System;
using MapRDB.Driver;
using MapRDB.Driver.Ojai;

public class FindQueryWithConditionJson
{
	public async void FindQueryWithConditionJson()
	{
        // Create a connection to data access server
        var connectionStr = $"localhost:5678?auth=basic;" +
            $"user=mapr;" +
            $"password=mapr;" +
            $"ssl=true;" +
            $"sslCA=/opt/mapr/conf/ssl_truststore.pem;" +
            $"sslTargetNameOverride=node1.mapr.com";
        var connection = ConnectionFactory.CreateConnection(connectionStr);

        // Get a store and assign it as a DocumentStore object
        var store = connection.GetStore("/demo_table");

        // Create an OJAI query
        var query =
            @"{" +
                @"""$where"":" +
                    @"{" +
                        @"""$eq"":{""address.zipCode"":{""$numberLong"":""95196""}}" +
                    @"}" +
            @"}";

        // Fetch OJAI Documents by query
        var queryResult = store.FindQuery(query);

        var documentStream = await queryResult.GetAllDocuments();
        // Print OJAI Documents from document stream
        foreach (var document in documentStream)
        {
            Console.WriteLine(document.ToDictionary());
        }

        // Close the OJAI connection
        connection.Close();
    }
}

Go - OJAI `QueryCondition` Object

The following example shows how to return all documents from a store where address.zipCode equals 95196, using the Query.WhereCondition function. It uses an OJAI Condition to specify the condition.

package main

import (
	"fmt"
	client "github.com/mapr/private-maprdb-go-client"
)

func main() {
	// Create connection string
	connectionString := "192.168.33.11:5678?" +
		"auth=basic;" +
		"user=mapr;" +
		"password=mapr;" +
		"ssl=true;" +
		"sslCA=/opt/mapr/conf/ssl_truststore.pem;" +
		"sslTargetNameOverride=node1.cluster.com"

	storeName := "/demo_table"

	// Create a connection to DAG
	connection, err := client.MakeConnection(connectionString)
	if err != nil {
		panic(err)
	}

	// Get a store and assign it as a DocumentStore struct
	store, err := connection.GetStore(storeName)
	if err != nil {
		panic(err)
	}

	// Options for find request
	options := &client.FindOptions{ResultAsDocument: true}

	// Create a condition
	condition, err := client.MakeCondition(client.Is("address.zipCode", client.EQUAL, 95196), client.Close())
	if err != nil {
		panic(err)
	}
	condition.Build()

	// Create an OJAI query
	query, err := client.MakeQuery(client.WhereCondition(condition))
	if err != nil {
		panic(err)
	}
	query.Build()

	// Fetch all OJAI Documents from table
	findResult, err := store.FindQuery(query, options)

	// Print OJAI Documents from document stream
	for _, doc := range findResult.DocumentList() {
		fmt.Println(doc)
	}

	// Close connection
	connection.Close()
}

Go - OJAI Query Condition in JSON Format

The following example uses an OJAI query condition specified in JSON format to return all documents from a store where address.zipCode equals 95196.

package main

import (
	"fmt"
	client "github.com/mapr/private-maprdb-go-client"
)

func main() {
	// Create connection string
	connectionString := "192.168.33.11:5678?" +
		"auth=basic;" +
		"user=mapr;" +
		"password=mapr;" +
		"ssl=true;" +
		"sslCA=/opt/mapr/conf/ssl_truststore.pem;" +
		"sslTargetNameOverride=node1.cluster.com"

	storeName := "/demo_table"

	// Create a connection to DAG
	connection, err := client.MakeConnection(connectionString)
	if err != nil {
		panic(err)
	}

	// Get a store and assign it as a DocumentStore struct
	store, err := connection.GetStore(storeName)
	if err != nil {
		panic(err)
	}

	// Options for find request
	options := &client.FindOptions{ResultAsDocument: true}

	// Create an OJAI query
	query := map[string]interface{}{
		"$where": map[string]interface{}{
			"$eq": map[string]interface{}{
				"address.zipCode": 95196}}}

	// Fetch all OJAI Documents from table
	findResult, err := store.FindQueryMap(query, options)

	// Print OJAI Documents from document stream
	for _, doc := range findResult.DocumentList() {
		fmt.Println(doc)
	}

	// Close connection
	connection.Close()
}

Querying with Conditions

Java - OJAI QueryCondition Object

Java - OJAI Query Condition in JSON Format

Node.js - OJAI Query Condition in JSON Format

Python - OJAI QueryCondition Object

Python - OJAI Query Condition in JSON Format

dbshell

C# - OJAI QueryCondition Object

C# - OJAI Query Condition in JSON Format

Go - OJAI QueryCondition Object

Go - OJAI Query Condition in JSON Format

Java - OJAI `QueryCondition` Object

Python - OJAI `QueryCondition` Object

C# - OJAI `QueryCondition` Object

Go - OJAI `QueryCondition` Object