class DuckDB::DataChunk

The DuckDB::DataChunk represents a chunk of data for table function output.

During table function execution, data chunks are used to return rows.

Example:

done = false
table_function.init { |_init_info| done = false }

table_function.execute do |func_info, output|
  if done
    output.size = 0  # Signal completion
  else
    # High-level API
    output.set_value(0, 0, 42)        # column 0, row 0, value 42
    output.set_value(1, 0, 'Alice')   # column 1, row 0, value 'Alice'
    output.size = 1
    done = true
  end
end

Public Instance Methods

column_count → Integer

Source

static VALUE rbduckdb_data_chunk_column_count(VALUE self) {
    rubyDuckDBDataChunk *ctx;
    idx_t count;

    TypedData_Get_Struct(self, rubyDuckDBDataChunk, &data_chunk_data_type, ctx);

    count = duckdb_data_chunk_get_column_count(ctx->data_chunk);

    return ULL2NUM(count);
}

Returns the number of columns in the data chunk.

data_chunk.column_count  # => 2

get_vector(col_idx) → DuckDB::Vector

Source

static VALUE rbduckdb_data_chunk_get_vector(VALUE self, VALUE col_idx) {
    rubyDuckDBDataChunk *ctx;
    idx_t idx;
    duckdb_vector vector;
    VALUE vector_obj;
    rubyDuckDBVector *vector_ctx;

    TypedData_Get_Struct(self, rubyDuckDBDataChunk, &data_chunk_data_type, ctx);

    idx = NUM2ULL(col_idx);
    vector = duckdb_data_chunk_get_vector(ctx->data_chunk, idx);

    // Create Vector wrapper
    vector_obj = rb_class_new_instance(0, NULL, cDuckDBVector);
    vector_ctx = get_struct_vector(vector_obj);
    vector_ctx->vector = vector;

    return vector_obj;
}

Gets the vector at the specified column index.

vector = data_chunk.get_vector(0)

set_value (col_idx, row_idx, value)

Source

# File lib/duckdb/data_chunk.rb, line 48
def set_value(col_idx, row_idx, value)
  vector = get_vector(col_idx)
  logical_type = vector.logical_type
  type_id = logical_type.type

  # Handle NULL
  if value.nil?
    vector.set_validity(row_idx, false)
    return value
  end

  case type_id
  when :boolean
    data = vector.get_data
    MemoryHelper.write_boolean(data, row_idx, value)
  when :tinyint
    data = vector.get_data
    MemoryHelper.write_tinyint(data, row_idx, value)
  when :smallint
    data = vector.get_data
    MemoryHelper.write_smallint(data, row_idx, value)
  when :integer
    data = vector.get_data
    MemoryHelper.write_integer(data, row_idx, value)
  when :bigint
    data = vector.get_data
    MemoryHelper.write_bigint(data, row_idx, value)
  when :utinyint
    data = vector.get_data
    MemoryHelper.write_utinyint(data, row_idx, value)
  when :usmallint
    data = vector.get_data
    MemoryHelper.write_usmallint(data, row_idx, value)
  when :uinteger
    data = vector.get_data
    MemoryHelper.write_uinteger(data, row_idx, value)
  when :ubigint
    data = vector.get_data
    MemoryHelper.write_ubigint(data, row_idx, value)
  when :float
    data = vector.get_data
    MemoryHelper.write_float(data, row_idx, value)
  when :double
    data = vector.get_data
    MemoryHelper.write_double(data, row_idx, value)
  when :varchar
    vector.assign_string_element(row_idx, value.to_s)
  when :blob
    vector.assign_string_element_len(row_idx, value.to_s)
  when :timestamp
    data = vector.get_data
    MemoryHelper.write_timestamp(data, row_idx, value)
  when :timestamp_tz
    data = vector.get_data
    MemoryHelper.write_timestamp_tz(data, row_idx, value)
  when :date
    data = vector.get_data
    MemoryHelper.write_date(data, row_idx, value)
  else
    raise ArgumentError, "Unsupported type for DataChunk#set_value: #{type_id} for value `#{value.inspect}`"
  end

  value
end

Sets a value at the specified column and row index. Type conversion is automatic based on the column’s logical type.

@param col_idx [Integer] Column index (0-based) @param row_idx [Integer] Row index (0-based) @param value [Object] Value to set (Integer, Float, String, Time, Date, nil) @return [Object] The value that was set

@example Set integer value

output.set_value(0, 0, 42)

@example Set string value

output.set_value(1, 0, 'hello')

@example Set NULL value

output.set_value(0, 1, nil)

rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/MethodLength

size → Integer

Source

static VALUE rbduckdb_data_chunk_get_size(VALUE self) {
    rubyDuckDBDataChunk *ctx;
    idx_t size;

    TypedData_Get_Struct(self, rubyDuckDBDataChunk, &data_chunk_data_type, ctx);

    size = duckdb_data_chunk_get_size(ctx->data_chunk);

    return ULL2NUM(size);
}

Returns the current number of tuples in the data chunk.

data_chunk.size  # => 100

size = size → size

Source

static VALUE rbduckdb_data_chunk_set_size(VALUE self, VALUE size) {
    rubyDuckDBDataChunk *ctx;
    idx_t sz;

    TypedData_Get_Struct(self, rubyDuckDBDataChunk, &data_chunk_data_type, ctx);

    sz = NUM2ULL(size);
    duckdb_data_chunk_set_size(ctx->data_chunk, sz);

    return size;
}

Sets the number of tuples in the data chunk.

data_chunk.size = 50