How to update an Entity in Table Storage if same ETag persists (Javascript package)

vaira selvam 20 Reputation points
2023-03-31T18:10:09.7266667+00:00

Hi,

I am using @azure/data-tables javascript package to access the Table storage. 

Trying to increment the count of a property in an Entity maintaining the Concurrency. How to perform the same using Etag property. I don't see any good examples in javascript.

Example: I will read "BuyersCount" property from Table and increment its value and overwrite the new value. 
Azure Table Storage
Azure Table Storage
An Azure service that stores structured NoSQL data in the cloud.
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Accepted answer
  1. Susheel Bhatt 351 Reputation points
    2023-04-03T08:02:12.52+00:00

    To update an entity in Azure Table Storage while maintaining concurrency, you can use the updateEntity method from the @azure/data-tables package. This method takes an entity object as a parameter, which should include the PartitionKey, RowKey, and any properties you want to update. It also takes an optional options parameter, which can include the ifMatch property to specify the ETag value to match.

    Here's an example code snippet to increment the BuyersCount property of an entity with a specified PartitionKey and RowKey:

    const { TableClient } = require("@azure/data-tables");
    
    // Initialize the TableClient
    const connectionString = "<your connection string>";
    const tableName = "<your table name>";
    const tableClient = new TableClient(connectionString, tableName);
    
    // Define the entity to update
    const partitionKey = "<your partition key>";
    const rowKey = "<your row key>";
    const entityToUpdate = {
      PartitionKey: partitionKey,
      RowKey: rowKey,
      BuyersCount: <current value>, // Replace with the current value of the property
    };
    
    // Define the options for the update operation
    const options = {
      ifMatch: <current ETag>, // Replace with the current ETag value of the entity
    };
    
    // Increment the BuyersCount property
    entityToUpdate.BuyersCount++;
    
    // Update the entity
    await tableClient.updateEntity(entityToUpdate, options);
    
    
    1 person found this answer helpful.

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