Tablestore:Delete data

Delete a single row

• Delete a row

  The following sample code provides an example on how to delete a 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 data table. 
      RowDeleteChange rowDeleteChange = new RowDeleteChange("<TABLE_NAME>", primaryKey);
  
      client.deleteRow(new DeleteRowRequest(rowDeleteChange));
  }                    

• Use a condition to delete a row

  The following sample code provides an example on how to delete a row of data from a data table when the row exists and the value of the Col0 column in the 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 data 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

1. Before you delete data, choose a method to query for the primary keys of the rows you want to delete.

   • To delete rows within a specific primary key range, use the GetRange operation to retrieve their primary keys. For more information, see Read data.

   • To delete rows that meet specific criteria, create a search index. Then, use the search index to query for the data and retrieve the primary keys of the rows to be deleted. For more information, see Create a search index and Use an SDK to query data with a search index.

2. Once you have the primary keys, call the BatchWriteRow operation to delete the rows. For more information, see Batch write data.

   The following sample code provides an example on how to delete a row of data in which the value of the pk primary key column is pk from a data table and a row of data in which the value of the pk1 primary key column is pk1 and the value of the pk2 primary key column is pk2 from another data table at the same 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 data 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 data 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 operations on failed rows. In this example, only the retry request is constructed. 
            * We recommend that you use the custom retry policy in Tablestore SDKs as the retry method. This feature allows you to retry failed rows after batch operations are performed. After you specify the retry policy, you do not need to add retry code to call the operation. 
            */
           BatchWriteRowRequest retryRequest = batchWriteRowRequest.createRequestForRetry(response.getFailedRows());
       }
   }