Operations · 4 min read

BulkUpdate

This method updates existing rows in the database in bulk, matched by the defined qualifiers. It is supported for SAP HANA.

This page documents the SAP HANA-specific arguments and examples. For the SQL Server implementation, see BulkUpdate (SQL Server).

Call Flow Diagram

The diagram below shows the flow when calling this operation.

flowchart TD
    Client["Client<br/>(RepoDB)"] -->|BulkUpdate| Source["Entities /<br/>DataTable /<br/>DbDataReader"]
    Source --> Guard{"Any updateable<br/>field left after<br/>excluding qualifiers?"}
    Guard -->|NO| Skip["Return 0<br/>(no pseudo table created)"]
    Guard -->|YES| Pseudo["Create Pseudo Table<br/>(deterministic name) +<br/>Index on qualifiers"]
    Pseudo --> Loader["Buffered row-by-row<br/>parameterized INSERT"]
    Loader -->|Write| PseudoTable[("Pseudo Table")]
    PseudoTable -->|"UPDATE Target SET (...) =<br/>(SELECT ... FROM Pseudo)<br/>WHERE EXISTS (...)<br/>(correlated subquery, no INSERT step)"| Table[("Target Table")]
    PseudoTable -->|Drop| Cleanup(["Pseudo Table Dropped"])

Use Case

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

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

A pseudo (staging) table, indexed on the qualifier columns, is created under a deterministic name for every call. The library writes to it row-by-row internally, then cascades the changes to the target table — see Operations (SAP HANA) for the underlying mechanics and its concurrency caveat.

SAP HANA has no multi-table UPDATE ... JOIN, so the cascading statement assigns every updateable column at once via a correlated subquery (SET (col1, col2, ...) = (SELECT ...)), guarded by a matching WHERE EXISTS clause — not an UPDATE ... FROM join. Staged rows with no matching target row are left as-is, not inserted.

Special Arguments

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

qualifiers defines the fields used to match existing rows, corresponding to the WHERE EXISTS correlation. Defaults to the primary or identity column if not specified.

mappings (via SapHanaBulkInsertMapItem) defines explicit column mappings between the source properties and the destination columns, with an optional HanaDbType override per mapping. When omitted, columns are auto-mapped by name (case-insensitive).

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.

If every staged field is also a qualifier (nothing left to actually update), the operation returns 0 immediately — no pseudo table is created at all.

Usability

Given a list of Person models, the following example bulk-updates rows in the Person table.

using (var connection = new HanaConnection(connectionString))
{
    var updatedRows = connection.BulkUpdate(people);
}

To specify a batch size:

using (var connection = new HanaConnection(connectionString))
{
    var updatedRows = connection.BulkUpdate(people, batchSize: 100);
}

batchSize only controls the client-side buffer; each row is still its own round trip.

DataTable

using (var connection = new HanaConnection(connectionString))
{
    var table = ConvertToDataTable(people);
    var updatedRows = connection.BulkUpdate("\"Person\"", table);
}

Dictionary/ExpandoObject

using (var sourceConnection = new HanaConnection(sourceConnectionString))
{
    var result = sourceConnection.QueryAll("\"Person\"");
    using (var destinationConnection = new HanaConnection(destinationConnectionString))
    {
        var updatedRows = destinationConnection.BulkUpdate("\"Person\"", result,
            qualifiers: Field.From("Name"));
    }
}

DataReader

using (var sourceConnection = new HanaConnection(sourceConnectionString))
{
    using (var reader = sourceConnection.ExecuteReader("SELECT * FROM \"Person\" WHERE \"Age\" > 18"))
    {
        using (var destinationConnection = new HanaConnection(destinationConnectionString))
        {
            var rows = destinationConnection.BulkUpdate("\"Person\"", reader);
        }
    }
}

To bulk-update via DataEntityDataReader:

using (var connection = new HanaConnection(connectionString))
{
    var people = GetPeople(10000);
    using (var reader = new DataEntityDataReader<Person>(people))
    {
        var updatedRows = connection.BulkUpdate("\"Person\"", reader);
    }
}

Field Qualifiers

By default, the primary or identity column is used as the qualifier. To override, pass a list of Field objects in the qualifiers argument.

using (var connection = new HanaConnection(connectionString))
{
    var people = GetPeople(10000);
    var updatedRows = connection.BulkUpdate<Person>(people,
        qualifiers: e => new { e.Name });
}

Use indexed columns from the target table as qualifiers to maximize performance.

Column Mappings

Add column mappings using the SapHanaBulkInsertMapItem class.

var mappings = new List<SapHanaBulkInsertMapItem>();

// Add the mappings
mappings.Add(new SapHanaBulkInsertMapItem("SourceId", "DestinationId"));
mappings.Add(new SapHanaBulkInsertMapItem("SourceName", "DestinationName"));
mappings.Add(new SapHanaBulkInsertMapItem("SourceAge", "DestinationAge"));
mappings.Add(new SapHanaBulkInsertMapItem("SourceCreatedDateUtc", "DestinationCreatedDateUtc"));

// Execute
using (var connection = new HanaConnection(connectionString))
{
    var people = GetPeople(10000);
    var updatedRows = connection.BulkUpdate(people,
        mappings: mappings);
}

Targeting a Table

To target a specific table, pass the literal table name.

using (var connection = new HanaConnection(connectionString))
{
    var people = GetPeople(10000);
    var updatedRows = connection.BulkUpdate("\"Person\"", people);
}

Async Method

An equivalent BulkUpdateAsync method is also available.

using (var connection = new HanaConnection(connectionString))
{
    var updatedRows = await connection.BulkUpdateAsync(people);
}