BulkDelete

This method deletes rows from the database in bulk, matched by the defined qualifiers. It is supported for EnterpriseDB. EnterpriseDB also has a dedicated BulkDeleteByKey operation for deleting by primary key.

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

Call Flow Diagram

The diagram below shows the flow when calling this operation.

flowchart TD
    Client["Client<br/>(RepoDB)"] -->|BulkDelete| Source["Entities /<br/>DataTable /<br/>DbDataReader"]
    Source --> Pseudo["Create Pseudo Table<br/>(Auto/Memory/Physical) +<br/>Index on qualifiers"]
    Pseudo --> Loader["EDBBulkCopy<br/>(Npgsql binary COPY,<br/>qualifier columns only)"]
    Loader -->|Write| PseudoTable[("Pseudo Table")]
    PseudoTable -->|"DELETE FROM Target<br/>USING Pseudo S<br/>WHERE (qualifiers match)"| Table[("Target Table")]
    PseudoTable -->|Drop| Cleanup(["Pseudo Table Dropped"])

Use Case

Use this method to delete rows against EnterpriseDB at high speed. It leverages RepoDb.Connector.EnterpriseDb’s EDBBulkCopy, itself built on top of Npgsql’s native binary COPY protocol — a genuine bulk load, not a client-side loop of single-row statements.

A pseudo (staging) table, containing only the qualifier columns and indexed on them, is created for every call and dropped afterward. The library writes to it via EDBBulkCopy, then cascades the deletions to the target table via a DELETE ... USING join — see Operations (EnterpriseDB) for the underlying mechanics.

Special Arguments

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

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

bulkCopyTimeout overrides the command timeout, in seconds, applied to the underlying EDBBulkCopy write while staging.

batchSize overrides the number of rows written per batch. When not set, the provider’s default batch size is used.

pseudoTableType (via EDBBulkImportPseudoTableType) controls the kind of staging table used — Auto (default) picks Physical once the row count reaches the internal threshold (5000), otherwise Memory.

Usability

The following example retrieves all inactive people, then bulk-deletes them from the Person table.

using (var connection = new EDBConnection(connectionString))
{
    var people = connection.Query<Person>(e => e.IsActive == false);
    var deletedRows = connection.BulkDelete<Person>(people);
}

To specify a batch size:

using (var connection = new EDBConnection(connectionString))
{
    var deletedRows = connection.BulkDelete<Person>(people, batchSize: 100);
}

DataTable

using (var connection = new EDBConnection(connectionString))
{
    var table = ConvertToDataTable(people);
    var deletedRows = connection.BulkDelete("\"Person\"", table);
}

Dictionary/ExpandoObject

using (var sourceConnection = new EDBConnection(sourceConnectionString))
{
    var result = sourceConnection.QueryAll("\"Person\"");
    using (var destinationConnection = new EDBConnection(destinationConnectionString))
    {
        var deletedRows = destinationConnection.BulkDelete("\"Person\"", result);
    }
}

DataReader

using (var sourceConnection = new EDBConnection(sourceConnectionString))
{
    using (var reader = sourceConnection.ExecuteReader("SELECT * FROM \"Person\""))
    {
        using (var destinationConnection = new EDBConnection(destinationConnectionString))
        {
            var deletedRows = destinationConnection.BulkDelete("\"Person\"", reader);
        }
    }
}

Targeting a Table

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

using (var connection = new EDBConnection(connectionString))
{
    var deletedRows = connection.BulkDelete("\"Person\"", people);
}

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 EDBConnection(connectionString))
{
    var deletedRows = connection.BulkDelete<Person>(people,
        qualifiers: e => new { e.Name });
}

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

Async Method

An equivalent BulkDeleteAsync method is also available.

using (var connection = new EDBConnection(connectionString))
{
    var people = connection.Query<Person>(e => e.IsActive == false);
    var deletedRows = await connection.BulkDeleteAsync<Person>(people);
}