thomas-k-cameron commented on code in PR #2969: URL: https://github.com/apache/arrow-datafusion/pull/2969#discussion_r930963112
########## datafusion-examples/examples/deserialize_to_struct.rs: ########## @@ -0,0 +1,75 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use datafusion::error::Result; +use datafusion::prelude::*; +use serde::Deserialize; + +/// This example shows that it is possible to convert query results into Rust structs . +/// It will collect the query results into RecordBatch, then convert it to serde_json::Value. +/// Then, serde_json::Value is turned into Rust's struct. +/// Any datatype with `Deserialize` implemeneted works. +#[tokio::main] +async fn main() -> Result<()> { + let data_list = Data::new().await?; + println!("{:#?}", data_list); + Ok(()) +} + +#[derive(Deserialize, Debug)] +struct Data { + #[allow(dead_code)] + int_col: i64, + #[allow(dead_code)] + double_col: f64, +} + +impl Data { + pub async fn new() -> Result<Vec<Self>> { + // this group is almost the same as the one you find it in parquet_sql.rs + let batches = { + let ctx = SessionContext::new(); + + let testdata = datafusion::test_util::parquet_test_data(); + + ctx.register_parquet( + "alltypes_plain", + &format!("{}/alltypes_plain.parquet", testdata), + ParquetReadOptions::default(), + ) + .await?; + + let df = ctx + .sql("SELECT int_col, double_col FROM alltypes_plain") + .await?; + + df.show().await?; + + df.collect().await? + }; + // converts it to serde_json type and then convert that into Rust type + let list = Review Comment: Thanks :D -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
