Delete rows (C#)

Finds rows in a table using filter clauses, and then deletes those rows.

If you don’t use a filter, or if you use an empty filter, then this method deletes all rows in the table.

Deleting rows produces tombstones. Excessive tombstones can impact query performance.

For general information about working with tables and rows, see About tables with the Data API (C#).

Ready to write code? See the examples for this method to get started. If you are new to the Data API, check out the quickstart.

Result

Deletes rows that match the specified parameters. If no rows match the specified parameters, this method does not delete any rows.

Does not return anything.

Parameters

Use the DeleteManyAsync method, which belongs to the Table class. You can also use DeleteMany, which is the synchronous version of the method.

Method signature

public Task DeleteManyAsync(
  TableFilter<T> filter, TableDeleteManyOptions options = null
);

For best performance, filter and sort on indexed columns, partition keys, and clustering keys.

Filtering on non-indexed columns is inefficient and resource-intensive, especially for large datasets. With the Data API clients, such operations can hit the client timeout limit before the underlying HTTP operation is complete. If you filter on non-indexed columns, the Data API will give a warning.

An empty filter or omitted filter may also result in an inefficient and long-running operation.

Additionally, the Data API can perform in-memory sorting, depending on the columns you sort on, the table’s partitioning structure, and whether the sorted columns are indexed. In-memory sorts can have performance implications.

Name Type Summary

filter

TableFilter

The filter criteria, defined using the Data API filter syntax.

If no filter or an empty filter is used, all rows are deleted.

If not empty, the filter depends on the table’s primary key definition:

For tables with a single-column primary key: the filter must include the primary key, and it cannot include any other columns.
For tables with a composite primary key: the filter must include all partition keys, and it cannot include any columns outside of the primary key definition.
For tables with a compound primary key: the filter must include all partition keys. It can include optional clustering keys, but it cannot include columns outside of the primary key definition.

If you include clustering keys, you must include them in the order specified in the primary key definition. You can omit clustering keys, but you cannot skip any clustering keys. For example, if you have three clustering keys, a, b, and c, then you can include a and omit b and c. However, if you include b, then you must also include a.

Additionally, clustering keys allow only the $eq operator, with the exception of the last clustering key in the table’s primary key definition, which allows $eq, $ne, or range operators ($gt, $gte, $lt, and $lte). For example, if your table has three clustering keys, a, b, and c, then you can only use range operators with c.

If you don’t use a filter, or if you use an empty filter, then this method deletes all rows in the table.

options

TableDeleteManyOptions

Optional. General API options for this operation, including the timeout. For more information and examples, see Customize API interaction.

Examples

The following examples demonstrate how to delete rows in a table.

Delete a row by primary key

If the filter specifies the full primary key, only the row matching that full primary key is deleted.

In the following example, the table has a composite primary key with the columns title and author.

For more information, see Primary keys in tables (C#) and Filter operators for tables (C#).

using DataStax.AstraDB.DataApi;
using DataStax.AstraDB.DataApi.Core;
using DataStax.AstraDB.DataApi.Tables;

namespace Examples;

public class Program
{
  static async Task Main()
  {
    // Get an existing table
    var client = new DataAPIClient(
      new CommandOptions() { Destination = DataAPIDestination.HCD }
    );

    var database = client.GetDatabase(
      "API_ENDPOINT",
      DataAPIClient.UsernamePasswordTokenProvider(
        "USERNAME",
        "PASSWORD"
      ),
      "KEYSPACE_NAME"
    );

    var table = database.GetTable("TABLE_NAME");

    // Delete rows
    var filterBuilder = Builders<Row>.TableFilter;
    var filter = filterBuilder.And(
      filterBuilder.Eq("title", "Hidden Shadows of the Past"),
      filterBuilder.Eq("author", "John Anthony")
    );

    await table.DeleteManyAsync(filter);
  }
}

Delete rows in a table with a single-column primary key

If the table has a single-column primary key, the filter must include the column in the primary key, and it cannot include any other columns.

In the following example, the table has a single-column primary key with the column title.

For more information, see Primary keys in tables (C#) and Filter operators for tables (C#).

using DataStax.AstraDB.DataApi;
using DataStax.AstraDB.DataApi.Core;
using DataStax.AstraDB.DataApi.Tables;

namespace Examples;

public class Program
{
  static async Task Main()
  {
    // Get an existing table
    var client = new DataAPIClient(
      new CommandOptions() { Destination = DataAPIDestination.HCD }
    );

    var database = client.GetDatabase(
      "API_ENDPOINT",
      DataAPIClient.UsernamePasswordTokenProvider(
        "USERNAME",
        "PASSWORD"
      ),
      "KEYSPACE_NAME"
    );

    var table = database.GetTable("TABLE_NAME");

    // Delete rows
    var filter = Builders<Row>.TableFilter.Eq(
      "title",
      "Hidden Shadows of the Past"
    );
    await table.DeleteManyAsync(filter);
  }
}

Delete rows in a table with a composite primary key

If the table has a composite primary key, the filter must include all columns in the primary key definition (all partition keys), and it cannot include any other columns.

In the following example, the table has a composite primary key with the columns title and author.

For more information, see Primary keys in tables (C#) and Filter operators for tables (C#).

using DataStax.AstraDB.DataApi;
using DataStax.AstraDB.DataApi.Core;
using DataStax.AstraDB.DataApi.Tables;

namespace Examples;

public class Program
{
  static async Task Main()
  {
    // Get an existing table
    var client = new DataAPIClient(
      new CommandOptions() { Destination = DataAPIDestination.HCD }
    );

    var database = client.GetDatabase(
      "API_ENDPOINT",
      DataAPIClient.UsernamePasswordTokenProvider(
        "USERNAME",
        "PASSWORD"
      ),
      "KEYSPACE_NAME"
    );

    var table = database.GetTable("TABLE_NAME");

    // Delete rows
    var filterBuilder = Builders<Row>.TableFilter;
    var filter = filterBuilder.And(
      filterBuilder.Eq("title", "Hidden Shadows of the Past"),
      filterBuilder.Eq("author", "John Anthony")
    );

    await table.DeleteManyAsync(filter);
  }
}

Delete rows in a table with a compound primary key

If the table has a compound primary key, the filter must include all of the partition (grouping) columns in the primary key.

The filter can also include clustering (sorting) columns from the primary key:

The order of the clustering columns in the filter must match the order in the primary key definition. You can omit clustering keys, but you cannot skip any clustering keys. For example, if you have three clustering keys, a, b, and c, then you can include a and omit b and c. However, if you include b, then you must also include a.
The last clustering column can use range operators ($gt, $gte, $lt, and $lte) or the $eq operator. All other clustering columns can only use the $eq operator. For example, if your table has three clustering keys, a, b, and c, then you can only use range operators with c.

The filter cannot include any other columns.

In the following example, the table has a compound primary key with the partition column title and the clustering column rating.

For more information, see Primary keys in tables (C#) and Filter operators for tables (C#).

using DataStax.AstraDB.DataApi;
using DataStax.AstraDB.DataApi.Core;
using DataStax.AstraDB.DataApi.Tables;

namespace Examples;

public class Program
{
  static async Task Main()
  {
    // Get an existing table
    var client = new DataAPIClient(
      new CommandOptions() { Destination = DataAPIDestination.HCD }
    );

    var database = client.GetDatabase(
      "API_ENDPOINT",
      DataAPIClient.UsernamePasswordTokenProvider(
        "USERNAME",
        "PASSWORD"
      ),
      "KEYSPACE_NAME"
    );

    var table = database.GetTable("TABLE_NAME");

    // Delete rows
    var filterBuilder = Builders<Row>.TableFilter;
    var filter = filterBuilder.And(
      filterBuilder.Eq("title", "Hidden Shadows of the Past"),
      filterBuilder.Eq("rating", 4)
    );

    await table.DeleteManyAsync(filter);
  }
}

Delete all rows

To delete all rows, use an empty filter.

using DataStax.AstraDB.DataApi;
using DataStax.AstraDB.DataApi.Core;
using DataStax.AstraDB.DataApi.Tables;

namespace Examples;

public class Program
{
  static async Task Main()
  {
    // Get an existing table
    var client = new DataAPIClient(
      new CommandOptions() { Destination = DataAPIDestination.HCD }
    );

    var database = client.GetDatabase(
      "API_ENDPOINT",
      DataAPIClient.UsernamePasswordTokenProvider(
        "USERNAME",
        "PASSWORD"
      ),
      "KEYSPACE_NAME"
    );

    var table = database.GetTable("TABLE_NAME");

    // Delete rows
    await table.DeleteManyAsync(Builders<Row>.TableFilter.Empty());
  }
}

Client reference

For more information, see the client reference.

Delete rows (C#)

Result

Parameters

Examples

Delete a row by primary key

Delete rows in a table with a single-column primary key

Delete rows in a table with a composite primary key

Delete rows in a table with a compound primary key

Delete all rows

Client reference

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