Operations · 2 min read

BulkDeleteByKey

This method deletes rows from the database using a list of primary keys in bulk. It is supported only for DuckDB.

Call Flow Diagram

The diagram below shows the flow when calling this operation.

flowchart TD
    Client["Client<br/>(RepoDB)"] -->|BulkDeleteByKey| Keys["Primary Keys<br/>IEnumerable&lt;TPrimaryKey&gt;"]
    Keys --> Pseudo["Create Pseudo Table<br/>(TEMP by default,<br/>key column only)"]
    Pseudo --> Appender["DuckDbBulkAppender"]
    Appender -->|Write| PseudoTable[("Pseudo Table")]
    PseudoTable -->|"DELETE ... WHERE EXISTS<br/>(SELECT 1 ... JOIN ON key)"| Table[("Target Table")]
    PseudoTable -->|Drop| Cleanup(["Pseudo Table Dropped"])

Use Case

Use this method to delete rows by primary key at high speed. It leverages DuckDB.NET’s native DuckDBAppender via the DuckDbBulkAppender wrapper.

Special Arguments

The bulkCopyTimeout, batchSize and pseudoTableType arguments are available for this operation.

batchSize overrides the number of rows sent to the server per batch. When not set, all items are sent at once.

pseudoTableType (via DuckDbBulkImportPseudoTableType) controls the kind of staging table used internally.

Auto currently behaves exactly like Memory (a TEMP table) — see Operations (DuckDB) for details.

Usability

Pass the target table name and the list of primary keys to the operation.

using (var connection = new DuckDBConnection(ConnectionString))
{
    var primaryKeys = connection.Query<Person>(p => p.IsActive == false).Select(p => p.Id);
    var deletedRows = connection.BulkDeleteByKey("Person", primaryKeys);
}

It returns the number of rows deleted from the underlying table.

To specify a batch size:

using (var connection = new DuckDBConnection(ConnectionString))
{
    var primaryKeys = connection.Query<Person>(p => p.IsActive == false).Select(p => p.Id);
    var deletedRows = connection.BulkDeleteByKey("Person",
        primaryKeys,
        batchSize: 100);
}

Async Method

An equivalent BulkDeleteByKeyAsync method is also available.

using (var connection = new DuckDBConnection(ConnectionString))
{
    var primaryKeys = connection.Query<Person>(p => p.IsActive == false).Select(p => p.Id);
    var deletedRows = await connection.BulkDeleteByKeyAsync("Person", primaryKeys);
}