BulkUpdate

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

This page documents the Firebird-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 --> Pseudo["Create Pseudo Table<br/>(Auto/Memory/Physical) +<br/>Index on qualifiers"]
    Pseudo --> Batcher["FirebirdCommandBatcher<br/>(FbBatchCommand)"]
    Batcher -->|Write| PseudoTable[("Pseudo Table")]
    PseudoTable -->|"MERGE INTO ... USING ...<br/>WHEN MATCHED THEN UPDATE<br/>(no WHEN NOT MATCHED)"| Table[("Target Table")]
    PseudoTable -->|Drop| Cleanup(["Pseudo Table Dropped"])

Use Case

Use this method to update rows at high speed. It leverages FbBatchCommand, the FirebirdSql.Data.FirebirdClient driver’s native ADO.NET batching API, via FirebirdCommandBatcher.

For updating 1,000 or more rows, prefer this method over UpdateAll — Firebird’s IsMultiStatementExecutable setting is false, so UpdateAll issues one round trip per row.

A pseudo (staging) table, indexed on the qualifier columns, is created for every call. The library writes to it via FirebirdCommandBatcher internally, then cascades the changes to the target table via a MERGE ... WHEN MATCHED THEN UPDATE statement with no WHEN NOT MATCHED branch — staged rows with no matching target row are left as-is, not inserted. See Operations (Firebird) for the underlying mechanics.

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 ON clause. Defaults to the primary or identity column if not specified.

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

bulkCopyTimeout overrides the command timeout, in seconds. FbBatchCommand has no timeout-equivalent property, so this argument currently has nothing to apply to.

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

pseudoTableType (via FirebirdBulkImportPseudoTableType) 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 without creating a pseudo table at all.

Caveats

This operation creates a pseudo (staging) table for every call — a per-call, uniquely-named TABLE or GLOBAL TEMPORARY TABLE, per pseudoTableType. The database user must have permission to create tables, or an FbException will be thrown.

Every step (creating the pseudo table and its index, writing to it, the cascading MERGE, and dropping the pseudo table) is executed against the same transaction argument when one is supplied — since Firebird’s DDL is itself transactional, passing an explicit FbTransaction makes the whole pipeline atomic (a rollback undoes the pseudo table creation too). Without one, each step runs under its own implicit transaction, so a failure partway through can leave an orphaned pseudo table behind.

Usability

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

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

To specify a batch size:

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

When batchSize is not set, all rows are sent to the server in a single batch.

DataTable

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

Dictionary/ExpandoObject

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

DataReader

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

To bulk-update via DataEntityDataReader:

using (var connection = new FbConnection(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 FbConnection(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 FirebirdCommandBatcherMapItem class.

var mappings = new List<FirebirdCommandBatcherMapItem>();

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

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

Async Method

An equivalent BulkUpdateAsync method is also available.

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