Data conversion in Azure Table storage

Question

I have a simple Azure function that takes previous data from the table storage, uses it for producing a new row which is then recorded back to the same table. These rows have many different fields, some of them are integer, some of them are floating-point. But as I can see all they are stored as int64 numbers into the table. Sure all the fractions are lost. And second, it creates problems when I get this data into my web app as it doesn't work with 64-bit integers. If briefly, what happens inside the Azure function

export async function eventHubTrigger1(message: Message, context: InvocationContext): Promise<void> {
    context.log('Event hub function processed message:', message);
    const prevData: ProcessedRecord[] = context.extraInputs.get(tableInput) as ProcessedRecord[];
    const currData: DeviceData[] = context.extraInputs.get(blobInput) as DeviceData[];
    const row: ProcessedRecord = StatusEvaluatingFunction(prevData, message, trapData, context);
    context.extraOutputs.set(tableOutput, [row]);
}

this is what this "row" looks like

type ProcessedRecord = {
  PartitionKey: string;
  RowKey: string;
  Leak: number; // integer
  CycleCounts: number; // integer
  Status: number; // integer
  TotLossesKg: number; // double
  ...
};

and what it becomes when gets into the tableenter image description here

Is there any way to state explicitly the types of the values (like here) in a record that is stored into a table by means of an Azure function (particularly written in JS/TS)?

Googling didn't helped. Maybe, the most useful suggesttion I managed to find was just to keep all the data as strings in the table and convert them to numbers when necessary. But I hope there is a better way of resolving this problem.

Answer 1

Data conversion in Azure Table storage

TypeScript for a processed record that corresponds to Azure Table storage property types from this reference

Edm.Int32:

• JavaScript Equivalent: Number

Edm.Double:

• JavaScript Equivalent: Number

Edm.String:

• JavaScript Equivalent: String.

type ProcessedRecord = {
    PartitionKey: string;
    RowKey: string;
    Timestamp: Date;
    BooleanProperty: boolean;
    DateTimeProperty: Date;
    DoubleProperty: number;
    GuidProperty: string;
    Int32Property: number;
    Int64Property: number;
    StringProperty: string;
};

• Azure function to store data in an Azure Table storage table. However, the table stores all of the data as a String by default property, even though the data has different data types, such as integers, doubles, and strings.

• Using the below code, I was able to update the data in the Azure storage table using the event hub trigger.

• The below code uses Event Hub Trigger for incoming messages and inserts the received data into Azure Table Storage.

const { app } = require('@azure/functions');
const { TableClient, AzureNamedKeyCredential } = require("@azure/data-tables");

// Define the ProcessedRecord type
const ProcessedRecord = {
    PartitionKey: 'string',
    RowKey: 'string',
    Leak: 'number',
    CycleCounts: 'number',
    Status: 'number',
    TotLossesKg: 'number',
    // Add other properties as needed
};

app.eventHub('eventHubTrigger1', {
    connection: 'sampathRootManageSharedAccessKey_EVENTHUB',
    eventHubName: 'sampath',
    cardinality: 'many',
    handler: async (messages, context) => {
        const account = Azure Storage Account Name";
        const accountKey = "Azure Storage Account AccountKey ";
        const tableName = "Azure Storage Account TableName ";

        const credential = new AzureNamedKeyCredential(account, accountKey);
        const client = new TableClient(`https://${account}.table.core.windows.net`, tableName, credential);

        if (Array.isArray(messages)) {
            context.log(`Event hub function processed ${messages.length} messages`);
            for (const message of messages) {
                context.log('Event hub message:', message);

                // Assuming your message contains data to be inserted into the table
                const entity = {
                    PartitionKey: 'p2',
                    RowKey: 'r2',
                    Leak: 1,
                    CycleCounts: 2,
                    Status: 4,
                    TotLossesKg: 2.5,
                    // Add other properties as needed
                };

                try {
                    // Insert the entity into the table
                    await client.createEntity(entity);
                    context.log('Entity inserted into the table:', entity);
                } catch (error) {
                    context.log('Error inserting entity into the table:', error);
                }
            }
        } else {
            context.log('Event hub function processed message:', messages);
        }
    }
});

Output:

Azure Storage Table: