Struct DuckDbChunkReader

Gives access to the data within a result chunk.

Inherited Members

ValueType.Equals(object)

ValueType.GetHashCode()

ValueType.ToString()

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Namespace: Mallard

Assembly: Mallard.dll

Syntax

public readonly ref struct DuckDbChunkReader

Remarks

Access must be intermediated through this "ref struct" to ensure that pointers to memory allocated by the DuckDB native library can only be read from within a restricted scope. This "ref struct" is passed to the body of DuckDbChunkReadingFunc<TState, TReturn> and cannot be accessed outside of that body.

"Ref structs" cannot be ported across threads, which also increases performance, by making unnecessary all thread-safety checks when accessing a chunk through methods here.

Properties

Length

The length (number of rows) present in this chunk.

Declaration

public int Length { get; }

Property Value

Type	Description
int

Methods

GetColumnRaw<T>(int)

Get access to the raw data for one column for all the rows represented by this chunk.

Declaration

public DuckDbVectorRawReader<T> GetColumnRaw<T>(int columnIndex) where T : unmanaged, allows ref struct

Parameters

Type	Name	Description
int	columnIndex	The index of the column.

Returns

Type	Description
DuckDbVectorRawReader<T>	DuckDbVectorRawReader<T> representing the data for the column.

Type Parameters

Name	Description
T	The .NET type to bind the elements of the column to. This type must be what DuckDbVectorRawReader<T> accepts for the selected column.

Exceptions

Type	Condition
IndexOutOfRangeException	columnIndex is out of range, or this instance is default-initialized.

GetColumn<T>(int)

Get access to the data for one column for all the rows represented by this chunk.

Declaration

public DuckDbVectorReader<T> GetColumn<T>(int columnIndex)

Parameters

Type	Name	Description
int	columnIndex	The index of the column.

Returns

Type	Description
DuckDbVectorReader<T>	DuckDbVectorReader<T> representing the data for the column.

Type Parameters

Name	Description
T	The .NET type to bind the elements of the column to. This type must be compatible with the actual (dynamic) type of the column in DuckDB.

Exceptions

Type	Condition
IndexOutOfRangeException	columnIndex is out of range, or this instance is default-initialized.