Skip to content
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 2 additions & 1 deletion datafusion-examples/README.md
Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,8 @@ cargo run --example csv_sql
- [`catalog.rs`](examples/external_dependency/catalog.rs): Register the table into a custom catalog
- [`custom_datasource.rs`](examples/custom_datasource.rs): Run queries against a custom datasource (TableProvider)
- [`dataframe.rs`](examples/dataframe.rs): Run a query using a DataFrame against a local parquet file
- [`dataframe-to-s3.rs`](examples/external_dependency/dataframe-to-s3.rs): Run a query using a DataFrame against a parquet file from s3
- [`dataframe-to-s3.rs`](examples/external_dependency/dataframe-to-s3.rs): Run a query using a DataFrame against a parquet file from s3 and writing back to s3
- [`dataframe_output.rs`](examples/dataframe_output.rs): Examples of methods which write data out from a DataFrame
- [`dataframe_in_memory.rs`](examples/dataframe_in_memory.rs): Run a query using a DataFrame against data in memory
- [`deserialize_to_struct.rs`](examples/deserialize_to_struct.rs): Convert query results into rust structs using serde
- [`expr_api.rs`](examples/expr_api.rs): Create, execute, simplify and anaylze `Expr`s
Expand Down
76 changes: 76 additions & 0 deletions datafusion-examples/examples/dataframe_output.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,76 @@
// 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::{dataframe::DataFrameWriteOptions, prelude::*};
use datafusion_common::{parsers::CompressionTypeVariant, DataFusionError};

/// This example demonstrates the various methods to write out a DataFrame to local storage.
/// See datafusion-examples/examples/external_dependency/dataframe-to-s3.rs for an example
/// using a remote object store.
#[tokio::main]
async fn main() -> Result<(), DataFusionError> {
let ctx = SessionContext::new();

let mut df = ctx.sql("values ('a'), ('b'), ('c')").await.unwrap();

// Ensure the column names and types match the target table
df = df.with_column_renamed("column1", "tablecol1").unwrap();

ctx.sql(
"create external table
test(tablecol1 varchar)
stored as parquet
location './datafusion-examples/test_table/'",
)
.await?
.collect()
.await?;

// This is equivalent to INSERT INTO test VALUES ('a'), ('b'), ('c').
// The behavior of write_table depends on the TableProvider's implementation
// of the insert_into method.
df.clone()
.write_table("test", DataFrameWriteOptions::new())
.await?;

df.clone()
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I wonder if it would be valuable to update one of these options showing DataFrameWriteOptions

something like

// you can use DataFrameWriteOptions to control how the dataframe output is created
// for example: 
....

?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Just pushed up an update with a DataFrameWriteOptions example and added the new example to the README file

.write_parquet(
"./datafusion-examples/test_parquet/",
DataFrameWriteOptions::new(),
None,
)
.await?;

df.clone()
.write_csv(
"./datafusion-examples/test_csv/",
// DataFrameWriteOptions contains options which control how data is written
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

❤️

// such as compression codec
DataFrameWriteOptions::new().with_compression(CompressionTypeVariant::GZIP),
None,
)
.await?;

df.clone()
.write_json(
"./datafusion-examples/test_json/",
DataFrameWriteOptions::new(),
)
.await?;

Ok(())
}