Yes i wrote MongoDB operation in resolver. The code is following below

module.exports.createPatient = function createPatient(

    root,

    args,

    context = {},

    info,

) {

    let { server, version, req, res } = context;

    console.log('inside the create patient', context.req.body);

    console.log('context.server.db', context.server.db);

    let db = context.server.db;

    let version = context.version;

    let logger = context.server.logger;

    return new Promise((resolve, reject) => {

        db.patients.create(context.req.body, (err, patient) => {

            console.log('error:', err);

            console.log('patient:', patient);

            if (err) {

                logger.error(err);

                let error = errorUtils.internal(version, err.message);

                reject(errorUtils.formatErrorForGraphQL(error));

            } else {

                resolve(patient);

            }

        })

    });

};