BulkDeleteByKey

This method deletes rows from the database using a list of primary keys in bulk. It is supported only for Db2.

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 + Truncate<br/>Pseudo Table (Physical)"]
    Pseudo --> BulkCopy["DB2BulkCopy"]
    BulkCopy -->|Write| PseudoTable[("Pseudo Table<br/>(key column only)")]
    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 the native bulk operation from the IBM Data Server .NET Provider via the DB2BulkCopy class.

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 Db2BulkImportPseudoTableType) controls the kind of staging table used internally.

Every pseudoTableType value currently resolves to Physical at runtime — see Operations (Db2) for details.

Usability

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

using (var connection = new DB2Connection(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 DB2Connection(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 DB2Connection(connectionString))
{
    var primaryKeys = connection.Query<Person>(p => p.IsActive == false).Select(p => p.Id);
    var deletedRows = await connection.BulkDeleteByKeyAsync("Person", primaryKeys);
}