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Mastering Internet of Things

You're reading from  Mastering Internet of Things

Product type Book
Published in Mar 2018
Publisher Packt
ISBN-13 9781788397483
Pages 410 pages
Edition 1st Edition
Languages
Author (1):
Peter Waher Peter Waher
Profile icon Peter Waher
Toc

Table of Contents (24) Chapters close

Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
1. Preparing Our First Raspberry Pi Project 2. Creating a Sensor to Measure Ambient Light 3. Creating an Actuator for Controlling Illumination 4. Publishing Information Using MQTT 5. Publishing Data Using HTTP 6. Creating Web Pages for Your Devices 7. Communicating More Efficiently Using CoAP 8. Interoperability 9. Social Interaction with Your Devices Using XMPP 10. The Controller 11. Product Life Cycle 12. Concentrators and Bridges 13. Using an Internet of Things Service Platform 14. IoT Harmonization 15. Security for the Internet of Things 16. Privacy 1. Other Books You May Enjoy Index

Removing old data


We cannot continue storing new values without also having a plan for removing old ones. Doing so is easy. We choose to delete all records older than 100 minutes. This is done by first performing a search, and then deleting objects that are found in this search. The search is defined by using filters from the Waher.Persistence.Filters namespace:

foreach (LastMinute Rec2 in await Database.Find<LastMinute>( 
   new FilterFieldLesserThan("Timestamp",  
   Timestamp.AddMinutes(-100)))) 
{ 
   await Database.Delete(Rec2); 
} 

You can now execute the application, and monitor how the MinuteValues collection is being filled.

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