Rename MongoDB DBRef database name in all collections.

dbref_database_rename.js

var newDbName = 'comsave-miner';
db.getCollectionNames().forEach(function (collName) {
    var collDocsUpdated = 0;

    db[collName].find().forEach(function (r) {
        var refUpdated = false;

        Object.keys(r).forEach(function(rKey){
            if(!r[rKey]) {
                return;
            }

            var isObject = typeof r[rKey] === 'object';
            if(!isObject) {
                return;
            }
            
            if (r[rKey]['$db'] && r[rKey]['$db'].length > 0) {
                r[rKey]['$db'] = newDbName;
                refUpdated = true;
            }
            else if (r[rKey].length > 0 && typeof r[rKey][0] === 'object' && r[rKey][0]['$db'] && r[rKey][0]['$db'].length > 0) {
                r[rKey].forEach(function (innerR, i) {
                    r[rKey][i]["$db"] = newDbName;
                });
                refUpdated = true;
            }
        });

        if(refUpdated) {
            db[collName].replaceOne({ "_id": r._id }, r)
            collDocsUpdated++;
        }
    });

    print(collName + ' updated ' + collDocsUpdated + ' docs.')
});