Rust Arrow RecordBatch as Polars DataFrame

我经常需要从Microsoft SQL服务器获取大量数据，以便在Rust中使用Polar进行操作，根据企业安全策略，我或多或少都被迫使用ODBC进行这些连接.ODBC要求限制我使用像ConnectorX这样成熟且功能强大的库.我可以使用ARROW_ODBC将查询结果从Arrow连接并高效地读取到RecordBatch对象中，但无法将这些RecordBatch对象转换为Polars DataFrame.

因为RecordBatch和Series的实际数据组件具有相同的底层表示形式，所以我认为可以从RecordBatch的零拷贝创建DataFrame.

然而，在columns.push(Series::from_arrow(&schema.fields().get(i).unwrap().name(), *column)?);中，我得到了错误:

mismatched types
expected struct `std::boxed::Box<(dyn polars::export::polars_arrow::array::Array + 'static)>`
   found struct `Arc<dyn arrow::array::Array>`

我的印象是，Arc<dyn Array>是ArrayRef，是真正的问题，也许我有一个Arc<dyn arrow::array::Array>和Series::from_arrow()期待一个北极星Arc<Array>？如果是这样，我该如何解决？

我的完整代码如下以供参考.

use arrow_odbc::{odbc_api::{Environment, ConnectionOptions}, OdbcReaderBuilder};
use arrow::record_batch::RecordBatch;
use polars::prelude::*;
use anyhow::Result;

const CONNECTION_STRING: &str = "...";

pub fn test() -> Result<()> {

    let odbc_environment = Environment::new()?;
     
    let connection = odbc_environment.connect_with_connection_string(
        CONNECTION_STRING,
        ConnectionOptions::default()
    )?;

    let cursor = connection.execute("SELECT * FROM Backcast_Power_Plant_Map", ())?.unwrap();

    let arrow_record_batches = OdbcReaderBuilder::new().build(cursor)?;

    fn record_batch_to_dataframe(batch: &RecordBatch) -> Result<DataFrame, PolarsError> {
        let schema = batch.schema();
        let mut columns = Vec::with_capacity(batch.num_columns());
        for (i, column) in batch.columns().iter().enumerate() {
            columns.push(Series::from_arrow(&schema.fields().get(i).unwrap().name(), *column)?);
        }
        Ok(DataFrame::from_iter(columns))
    }

    for batch in arrow_record_batches {
        dbg!(record_batch_to_dataframe(&batch?));
    }

    Ok(())
}