Operations · 2 min read

BulkDeleteByKey

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

Unlike BulkDelete, this operation takes the target table name directly (BulkDeleteByKey<TPrimaryKey>(connection, tableName, primaryKeys, ...)) rather than an entity type parameter — there is no BulkDeleteByKey<TEntity, TPrimaryKey> overload.

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/>(deterministic name) +<br/>Index on key column"]
    Pseudo --> Loader["Buffered row-by-row<br/>parameterized INSERT<br/>(key column only)"]
    Loader -->|Write| PseudoTable[("Pseudo Table")]
    PseudoTable -->|"DELETE FROM Target<br/>WHERE EXISTS (SELECT 1 FROM<br/>Pseudo S WHERE key matches)"| Table[("Target Table")]
    PseudoTable -->|Drop| Cleanup(["Pseudo Table Dropped"])

Use Case

Use this method to delete rows by primary key against SAP HANA without hand-rolling the row-by-row loop yourself.

SAP HANA has no native bulk-load API, so writing the key values into the pseudo table is a client-buffered loop of single-row, parameterized INSERT statements — one round trip per row. The cascading DELETE against the real table, however, is a single native statement.

A pseudo (staging) table, containing only the key column and indexed on it, is created under a deterministic name for every call — see Operations (SAP HANA) for the underlying mechanics and its concurrency caveat.

Special Arguments

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

bulkCopyTimeout overrides the command timeout, in seconds, applied to each row’s INSERT while staging.

batchSize overrides how many rows are buffered client-side between flushes (default 500) — it does not change the number of round trips.

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

Usability

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

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

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

To specify a batch size:

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

Async Method

An equivalent BulkDeleteByKeyAsync method is also available.

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