Tablestore:Configure an auto-increment primary key column

Characteristics

The auto-increment primary key column feature has the following characteristics:

• The values of an auto-increment primary key column are unique and increase monotonically but not always continuously within a partition that shares the same partition key value.
• The values of an auto-increment primary key column are 64-bit signed integers of the LONG data type.
• You can create an auto-increment primary key column for a data table. An instance can include data tables that contain auto-increment primary key columns and tables that do not contain auto-increment primary key columns.

Limits

The auto-increment primary key column feature has the following limits:

• You can specify at most one auto-increment primary key column for a data table. You cannot specify the partition key as the auto-increment primary key column.
• You can specify an auto-increment primary key column only when you create a data table. You cannot specify an auto-increment primary key column for an existing data table.
• You can specify a primary key column only of the INTEGER type as the auto-increment primary key column. Each value generated for an auto-increment primary key column is a 64-bit signed integer of the LONG data type.
• You cannot specify an attribute column as the auto-increment primary key column.

API operations

Examples

You can use the auto-increment primary key column feature when you call the CreateTable, PutRow, UpdateRow, or BatchWriteRow operation.

1. Create a table

   To create an auto-increment primary key column when you create a table, you need to only set the attribute of the primary key column to AUTO_INCREMENT.

   private static void createTable(SyncClient client) {
       TableMeta tableMeta = new TableMeta("table_name");
       // Create the first primary key column. The first primary key column is the partition key. 
       tableMeta.addPrimaryKeyColumn(new PrimaryKeySchema("PK_1", PrimaryKeyType.STRING));
       // Create the second primary key column whose type is INTEGER, and specify the second primary key column as the auto-increment primary key column by setting the attribute of the second primary key column to AUTO_INCREMENT. 
       tableMeta.addPrimaryKeyColumn(new PrimaryKeySchema("PK_2", PrimaryKeyType.INTEGER, PrimaryKeyOption.AUTO_INCREMENT));
       int timeToLive = -1;  // Specify that data never expires. 
       int maxVersions = 1;  // Specify that only one version of data is retained. 
       TableOptions tableOptions = new TableOptions(timeToLive, maxVersions);
       CreateTableRequest request = new CreateTableRequest(tableMeta, tableOptions);
       client.createTable(request);
   }

2. Write data to a table

   When you write data to a table, you do not need to specify values for the auto-increment primary key column. You need to only set the values of the auto-increment primary key column to AUTO_INCREMENT.

   private static void putRow(SyncClient client, String receive_id) {
       // Construct the primary key. 
       PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder();
       // Set the values in the first primary key column to the first four digits of md5(receive_id). 
       primaryKeyBuilder.addPrimaryKeyColumn("PK_1", PrimaryKeyValue.fromString("Hangzhou");
       // The second primary key column is an auto-increment primary key column, and you do not need to specify values for the second primary key column. You need to only set the values of the auto-increment primary key column to AUTO_INCREMENT. Tablestore automatically generates values for the auto-increment primary key column. 
       primaryKeyBuilder.addPrimaryKeyColumn("PK_2", PrimaryKeyValue.AUTO_INCREMENT);
       PrimaryKey primaryKey = primaryKeyBuilder.build();
       RowPutChange rowPutChange = new RowPutChange("table_name", primaryKey);
       // Set ReturnType to RT_PK to include the primary key value in the response. If you do not set ReturnType to RT_PK, the primary key value is not included in the response. 
       rowPutChange.setReturnType(ReturnType.RT_PK);
       // Add attribute columns. 
       rowPutChange.addColumn(new Column("content", ColumnValue.fromString(content)));
       // Write data to the table. 
       PutRowResponse response = client.putRow(new PutRowRequest(rowPutChange));
       // Display the returned primary key value. 
       Row returnRow = response.getRow();
       if (returnRow != null) {
           System.out.println("PrimaryKey:" + returnRow.getPrimaryKey().toString());
       }
       // Display the consumed capacity units (CUs). 
       CapacityUnit  cu = response.getConsumedCapacity().getCapacityUnit();
       System.out.println("Read CapacityUnit:" + cu.getReadCapacityUnit());
       System.out.println("Write CapacityUnit:" + cu.getWriteCapacityUnit());
   }

Use Tablestore SDKs

You can use the following Tablestore SDKs to implement the auto-increment primary key column feature:

• Tablestore SDK for Java: Configure an auto-increment primary key column
• Tablestore SDK for Go: Configure an auto-increment primary key column
• Tablestore SDK for Python: Configure an auto-increment primary key column
• Tablestore SDK for Node.js: Configure an auto-increment primary key column
• Tablestore SDK for .NET: Configure an auto-increment primary key column
• Tablestore SDK for PHP: Configure an auto-increment primary key column

Billing

When you use the auto-increment primary key column feature, the existing billing rules are not affected. The primary key values that are returned do not consume additional read CUs.