Operations · 4 min read

BulkInsert

This method inserts all rows from the client application into the database in bulk. It is supported for Db2.

This page documents the Db2-specific arguments and examples. For the SQL Server implementation, see BulkInsert (SQL Server).

Call Flow Diagram

The diagram below shows the flow when calling this operation.

flowchart TD
    Client["Client<br/>(RepoDB)"] -->|BulkInsert| Source["Entities /<br/>DataTable /<br/>DbDataReader"]
    Source --> Decision{"identityBehavior ==<br/>ReturnIdentity?"}
    Decision -->|NO| Direct["DB2BulkCopy"]
    Direct -->|Write| Table[("Target Table")]
    Decision -->|YES| Pseudo["Create Pseudo Table<br/>(Physical) +<br/>row-order IDENTITY column"]
    Pseudo --> Staged["DB2BulkCopy"]
    Staged -->|Write| PseudoTable[("Pseudo Table")]
    PseudoTable --> Insert["SELECT id FROM FINAL TABLE(<br/>INSERT INTO ... SELECT ...<br/>FROM Pseudo ORDER BY row-order)<br/>ORDER BY id"]
    Insert --> Table
    Insert -->|"assign identities<br/>back to entities"| Client
    PseudoTable -->|Drop| Cleanup(["Pseudo Table Dropped"])

Use Case

Use this method to insert rows at high speed. It leverages the native bulk operation from the IBM Data Server .NET Provider via the DB2BulkCopy class.

For inserting 1,000 or more rows, prefer this method over InsertAll.

Rows are written straight to the target table. A staging table is only used when identityBehavior is set to ReturnIdentity (see below) — see Operations (Db2) for the underlying mechanics.

Special Arguments

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

mappings (via Db2BulkInsertMapItem) defines explicit column mappings between the source properties and the destination columns, with an optional DB2Type override per mapping. When omitted, columns are auto-mapped by name (case-insensitive).

bulkCopyTimeout overrides the command timeout, in seconds.

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

identityBehavior (via Db2BulkImportIdentityBehavior) controls whether newly generated identity values are set back on the data entities. Disabled (KeepIdentity) by default. Enabling this (ReturnIdentity) routes the operation through a staging table instead, reading the generated identity values back via Db2’s SELECT ... FROM FINAL TABLE (INSERT ...) clause.

pseudoTableType (via Db2BulkImportPseudoTableType) controls the kind of staging table used when identityBehavior is ReturnIdentity.

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

The DbDataReader overload has no identityBehavior argument — a forward-only, single-pass reader cannot be rewound to correlate generated identity values back onto a source row, so ReturnIdentity is not supported for that overload.

Identity Setting Alignment

When identityBehavior is ReturnIdentity, the library adds a __RepoDbBulkRowOrder__ identity column to the staging table to track each entity’s position in the source IEnumerable. The staged rows are then fed into the real INSERT ordered by that column, and the generated identities are read back — in the same statement — via SELECT identity FROM FINAL TABLE (INSERT ... ) ORDER BY identity, then assigned back to the correct entity via the compiled identity-setter function.

Usability

The following example defines a method that produces a list of Person objects, then bulk-inserts 10,000 rows into the Person table.

private IEnumerable<Person> GetPeople(int count = 1000)
{
    for (var i = 0; i < count; i++)
    {
        yield return new Person
        {
            Name = $"Person-{i}",
            SSN = Guid.NewGuid().ToString(),
            IsActive = true,
            DateInsertedUtc = DateTime.UtcNow
        };
    }
}

using (var connection = new DB2Connection(connectionString))
{
    var people = GetPeople(10000);
    var insertedRows = connection.BulkInsert(people);
}

To specify a batch size:

using (var connection = new DB2Connection(connectionString))
{
    var people = GetPeople(10000);
    var insertedRows = connection.BulkInsert(people, batchSize: 100);
}

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

To return the newly generated identity values:

using (var connection = new DB2Connection(connectionString))
{
    var people = GetPeople(10000);
    var insertedRows = connection.BulkInsert(people,
        identityBehavior: Db2BulkImportIdentityBehavior.ReturnIdentity);
}

DataTable

using (var connection = new DB2Connection(connectionString))
{
    var people = GetPeople(10000);
    var table = ConvertToDataTable(people);
    var insertedRows = connection.BulkInsert("Person", table);
}

Dictionary/ExpandoObject

using (var sourceConnection = new DB2Connection(sourceConnectionString))
{
    var result = sourceConnection.QueryAll("Person");
    using (var destinationConnection = new DB2Connection(destinationConnectionString))
    {
        var insertedRows = destinationConnection.BulkInsert("Person", result);
    }
}

DataReader

using (var sourceConnection = new DB2Connection(sourceConnectionString))
{
    using (var reader = sourceConnection.ExecuteReader("SELECT * FROM Person"))
    {
        using (var destinationConnection = new DB2Connection(destinationConnectionString))
        {
            var rows = destinationConnection.BulkInsert("Person", reader);
        }
    }
}

To bulk-insert via DataEntityDataReader:

using (var connection = new DB2Connection(connectionString))
{
    var people = GetPeople(10000);
    using (var reader = new DataEntityDataReader<Person>(people))
    {
        var insertedRows = connection.BulkInsert("Person", reader);
    }
}

Column Mappings

Add column mappings using the Db2BulkInsertMapItem class.

var mappings = new List<Db2BulkInsertMapItem>();

// Add the mappings
mappings.Add(new Db2BulkInsertMapItem("SourceId", "DestinationId"));
mappings.Add(new Db2BulkInsertMapItem("SourceName", "DestinationName"));
mappings.Add(new Db2BulkInsertMapItem("SourceIsActive", "DestinationIsActive"));
mappings.Add(new Db2BulkInsertMapItem("SourceDateInsertedUtc", "DestinationDateInsertedUtc"));

// Execute
using (var connection = new DB2Connection(connectionString))
{
    var people = GetPeople(10000);
    var insertedRows = connection.BulkInsert(people,
        mappings: mappings);
}

Targeting a Table

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

using (var connection = new DB2Connection(connectionString))
{
    var people = GetPeople(10000);
    var insertedRows = connection.BulkInsert("Person", people);
}

Async Method

An equivalent BulkInsertAsync method is also available.

using (var connection = new DB2Connection(connectionString))
{
    var people = GetPeople(10000);
    var insertedRows = await connection.BulkInsertAsync(people);
}