Class DuckDBAppender

Namespace

DuckDB.NET.Data

Assembly

DuckDB.NET.Data.dll

Appends rows to a DuckDB table.

public class DuckDBAppender : IDisposable

Inheritance

object

DuckDBAppender

Implements

IDisposable

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

Instances are not thread-safe. Do not call other methods on the same appender from an AppendRow<TState>(TState, Action<IDuckDBAppenderRow, TState>) callback.

Methods

AppendRow(Action<IDuckDBAppenderRow>)

Appends a complete row using a reusable row instance.

public void AppendRow(Action<IDuckDBAppenderRow> writeRow)

Parameters

writeRow Action<IDuckDBAppenderRow>

A callback that appends every column value. This method calls EndRow() after the callback returns.

Remarks

The row is valid only during the callback and must not be retained. The callback must not call other methods on this appender. If the callback or automatic EndRow() fails, the failed row is discarded and no more rows can be appended; the rows completed before the failure are still written when the appender is closed or disposed. Wrap the append in a transaction if you need all-or-nothing.

For large or hot-path loads, prefer the AppendRow<TState>(TState, Action<IDuckDBAppenderRow, TState>) overload with a static callback. A callback passed here that captures variables allocates a closure on every call; passing the captured data as the state argument to that overload keeps the append allocation-free.

AppendRow<TState>(TState, Action<IDuckDBAppenderRow, TState>)

Appends a complete row using a reusable row instance without exposing that instance as a return value. The row passed to writeRow is only valid for the duration of the callback and must not be retained or used after the callback returns.

public void AppendRow<TState>(TState state, Action<IDuckDBAppenderRow, TState> writeRow)

Parameters

state TState

The value used to populate the row.

writeRow Action<IDuckDBAppenderRow, TState>

A callback that appends every column value. This method calls EndRow() after the callback returns.

Type Parameters

TState

The type of value used to populate the row.

Remarks

The callback must not call other methods on this appender. If the callback or automatic EndRow() fails, the failed row is discarded and no more rows can be appended; the rows completed before the failure are still written when the appender is closed or disposed. Wrap the append in a transaction if you need all-or-nothing.

This overload is the allocation-free choice for hot paths: use a static callback and pass any per-row data through state so the callback captures nothing and no closure is allocated per row.

Clear()

public void Clear()

Close()

public void Close()

CreateRow()

Creates an independent row. The caller must append every column and call EndRow().

public IDuckDBAppenderRow CreateRow()

Returns

IDuckDBAppenderRow

Remarks

A new row instance is allocated on every call. Prefer AppendRow<TState>(TState, Action<IDuckDBAppenderRow, TState>), which reuses a single row instance and avoids the per-row allocation; use this method only when you need an independent row instance whose lifetime you control.

Dispose()

Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

public void Dispose()