Tablestore .NET SDK configure auto-increment primary key column - Tablestore

This topic explains how to configure an auto-increment primary key column for a data table using the .NET SDK, as well as how to write data to the column and retrieve the generated values.

Usage notes

The auto-increment values generated for an auto-increment column are unique and strictly incremental at the partition key level. However, they are not guaranteed to be consecutive.

Prerequisites

Initialize a Tablestore Client

Configure an auto-increment primary key column

You can configure a non-partition primary key column as an auto-increment column when you create a data table. For existing data tables, you cannot configure auto-increment columns.

Note

Only integer non-partition primary key columns can be configured as auto-increment columns. A data table can have at most one auto-increment column. The values generated for an auto-increment column are 64-bit signed long integers.

Sample code

The following sample code creates a data table named test_table. The primary key of the table includes the partition key id and the auto-increment column incr.

public static void CreateSample(OTSClient client)
{
    try
    {
        PrimaryKeySchema primaryKeySchema = new PrimaryKeySchema
        {
            { "id", ColumnValueType.String },
            { "incr", ColumnValueType.Integer, PrimaryKeyOption.AUTO_INCREMENT}
        };
        TableMeta tableMeta = new TableMeta("test_table", primaryKeySchema);
        CapacityUnit reservedThroughput = new CapacityUnit(0, 0);

        CreateTableRequest request = new CreateTableRequest(tableMeta, reservedThroughput);
        client.CreateTable(request);
        Console.WriteLine("Create table succeeded.");
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Create table failed, exception:{ex.Message}");
    }
}

Write data

When writing data to an auto-increment column, set the column value to a placeholder. To retrieve the generated auto-increment value for queries and updates, set the return type of RowPutChange to ReturnType.RT_PK.

Sample code

The following sample code writes a row of data to the test_table table, and gets and prints the primary key information of the written row data.

public static void PutRowSample(OTSClient client)
{
    try
    {
        // Construct the primary key
        PrimaryKey primaryKey = new PrimaryKey
        {
            { "id", new ColumnValue("row1") },
            { "incr",  ColumnValue.AUTO_INCREMENT }
        };

        // Construct the row data to write
        AttributeColumns attribute = new AttributeColumns
        {
            { "col1", new ColumnValue("val1") }
        };
        PutRowRequest request = new PutRowRequest("test_table", new Condition(RowExistenceExpectation.IGNORE), primaryKey, attribute);
        // Set the return type to ReturnType.RT_PK to return the primary key information of the written row data
        request.RowPutChange.ReturnType = ReturnType.RT_PK;

        // Call the PutRow method to write the row data
        PutRowResponse response = client.PutRow(request);

        // RequestId and consumed CU
        Console.WriteLine("RequestId: " + response.RequestID);
        Console.WriteLine("Read CU Cost: " + response.ConsumedCapacityUnit.Read);
        Console.WriteLine("Write CU Cost: " + response.ConsumedCapacityUnit.Write);

        // Get and print the returned primary key information. If the return type is not set to ReturnType.RT_PK, the primary key information is not returned by default
        Console.WriteLine(response.Row.PrimaryKey.ToString());
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Put Row failed, exception:{ex.Message}");
    }
}