Tablestore:Delete data

Delete a single row of data

• Delete a row of data

  The following sample code provides an example on how to delete a specific row of data from a table:

  private static void deleteRow(SyncClient client, String pkValue) {
      // Construct the primary key. 
      PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder();
      primaryKeyBuilder.addPrimaryKeyColumn("pk", PrimaryKeyValue.fromString(pkValue));
      PrimaryKey primaryKey = primaryKeyBuilder.build();
      // Specify the name of the table. 
      RowDeleteChange rowDeleteChange = new RowDeleteChange("<TABLE_NAME>", primaryKey);
  
      client.deleteRow(new DeleteRowRequest(rowDeleteChange));
  }                    

• Specify conditions when you delete data

  The following sample code provides an example on how to delete a specific row of data from a table if the specific row exists and the value of the Col0 column in the specific row is greater than 100:

  private static void deleteRow(SyncClient client, String pkValue) {
      // Construct the primary key. 
      PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder();
      primaryKeyBuilder.addPrimaryKeyColumn("pk", PrimaryKeyValue.fromString(pkValue));
      PrimaryKey primaryKey = primaryKeyBuilder.build();
      // Specify the name of the table. 
      RowDeleteChange rowDeleteChange = new RowDeleteChange("<TABLE_NAME>", primaryKey);
  
      // Specify conditions for the DeleteRow operation. In this example, a row is deleted only when the row exists and the value of the Col0 column is greater than 100. 
      Condition condition = new Condition(RowExistenceExpectation.EXPECT_EXIST);
      condition.setColumnCondition(new SingleColumnValueCondition("Col0",
              SingleColumnValueCondition.CompareOperator.GREATER_THAN, ColumnValue.fromLong(100)));
      rowDeleteChange.setCondition(condition);
  
      client.deleteRow(new DeleteRowRequest(rowDeleteChange));
  }                   

Delete multiple rows of data at a time

1. Before you delete data, select an appropriate method to query the primary key information of the data that you want to delete based on your business requirements.

   • To delete the data whose primary key values are in the specified range, call the GetRange operation to query the data and obtain the primary key information of the data. For more information, see Read data.

   • To delete the data that meets the specified conditions, use search indexes to query the data. Then, obtain the primary key information of the data. For more information, see Create search indexes and Use Tablestore SDKs.

2. After you obtain the primary key information of the data, call the BatchWriteRow operation to delete multiple rows of data at a time based on the primary key information. For more information, see the Write multiple rows of data at a time section of the "Write data" topic.

   The following sample code provides an example on how to delete a row of data whose value of the pk primary key column is pk in a table and a row of data whose value of the pk1 primary key column is pk1 and whose value of the pk2 primary key column is pk2 in another table at a time:

   private static void batchWriteRow(SyncClient client) {    
       BatchWriteRowRequest batchWriteRowRequest = new BatchWriteRowRequest();
   
       // Construct rowDeleteChange1. 
       PrimaryKeyBuilder pk1Builder = PrimaryKeyBuilder.createPrimaryKeyBuilder();
       pk1Builder.addPrimaryKeyColumn("pk", PrimaryKeyValue.fromString("pk"));
       // Specify the name of the table. 
       RowDeleteChange rowDeleteChange1 = new RowDeleteChange("<TABLE_NAME1>", pk1Builder.build());
       // Add rowDeleteChange1 to the code of the batch operation. 
       batchWriteRowRequest.addRowChange(rowDeleteChange1);
   
       // Construct rowDeleteChange2. 
       PrimaryKeyBuilder pk2Builder = PrimaryKeyBuilder.createPrimaryKeyBuilder();
       pk2Builder.addPrimaryKeyColumn("pk1", PrimaryKeyValue.fromString("pk1"));
       pk2Builder.addPrimaryKeyColumn("pk2", PrimaryKeyValue.fromString("pk2"));
       // Specify the name of the table. 
       RowDeleteChange rowDeleteChange2 = new RowDeleteChange("<TABLE_NAME2>", pk2Builder.build());
       // Add rowDeleteChange2 to the code of the batch operation. 
       batchWriteRowRequest.addRowChange(rowDeleteChange2);
   
       BatchWriteRowResponse response = client.batchWriteRow(batchWriteRowRequest);
   
       System.out.println("Whether all operations are successful:" + response.isAllSucceed());
       if (!response.isAllSucceed()) {
           for (BatchWriteRowResponse.RowResult rowResult : response.getFailedRows()) {
               System.out.println("Failed rows:" + batchWriteRowRequest.getRowChange(rowResult.getTableName(), rowResult.getIndex()).getPrimaryKey());
               System.out.println("Cause of failures:" + rowResult.getError());
           }
           /**
            * You can use the createRequestForRetry method to construct another request to retry the batch operation on failed rows. In this example, only the retry request is constructed. 
            * We recommend that you use the custom retry policy in Tablestore SDKs. You can use this policy to retry the batch operation on failed rows. After you configure the retry policy, you do not need to add retry code to call the operation. 
            */
           BatchWriteRowRequest retryRequest = batchWriteRowRequest.createRequestForRetry(response.getFailedRows());
       }
   }