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Not really... That is the &quot;benefit&quot; of KV storages.., except for the key &nbsp;anything is data. (so a change in content means scanning the database_)...<br />
It would help if the date of entry, or some sequence number, would be part of the Key, then you can at least start with the records from a certain date....<br />
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The best thing that could happen if the timezone is mentioned in all time stamps, than it doesn't matter.
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Not really... That is the "benefit" of KV storages.., except for the key  anything is data. (so a change in content means scanning the database_)...
It would help if the date of entry, or some sequence number, would be part of the Key, then you can at least start with the records from a certain date....

The best thing that could happen if the timezone is mentioned in all time stamps, than it doesn't matter.

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In MongoDb collection a DateTime field is stored in MST dateTime format for over 1 millions of record for a older record and now new records in utc dateTime format,<br />
&nbsp; Is there any cost effective query to update the date property in collections for those old recordsin MST dateTime <br />
&nbsp; (update the registered date format from MST to UTC format i.e. update time + 7:00 hr of each of these record)? We have MongoDb 3.3 version.
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In MongoDb collection a DateTime field is stored in MST dateTime format for over 1 millions of record for a older record and now new records in utc dateTime format,
  Is there any cost effective query to update the date property in collections for those old recordsin MST dateTime 
  (update the registered date format from MST to UTC format i.e. update time + 7:00 hr of each of these record)? We have MongoDb 3.3 version.

Update the MST date Format to UTC date format for records of  a period.

MongoDB (from humongous) is a free and open-source cross-platform document-oriented database program. Classified as a NoSQL database program, MongoDB uses JSON-like documents with schemas. MongoDB is developed by MongoDB Inc. and is free and open-source, published under a combination of the GNU Affero General Public License and the Apache License.

MongoDB

Databases are organized collections of data, most commonly accessed through management systems including schemas, tables, queries and processes that allow users to enter and manipulate the information or utilize it in other fashions, such as with web applications or for reporting purposes.

Databases

A NoSQL database provides a mechanism for storage and retrieval of data which is modeled in means other than the tabular relations used in relational databases. Motivations for this approach include: simplicity of design, simpler "horizontal" scaling to clusters of machines and finer control over availability. The data structures used by NoSQL databases (e.g. key-value, wide column, graph, or document) are specified from those used by default in relational databases, making some operations faster in NoSQL. Sometimes the data structures used by NoSQL databases are also viewed as "more flexible" than relational database tables.