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<p align="center">
  A native Rust library for Delta Lake, with bindings to Python
  <br>
  <a href="https://delta-io.github.io/delta-rs/">Python docs</a>
  ·
  <a href="https://docs.rs/deltalake/latest/deltalake/">Rust docs</a>
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  ·
  <a href="https://github.com/delta-io/delta-rs/issues/1128">Roadmap</a>
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  <a href="https://pypi.python.org/pypi/deltalake">
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Delta Lake is an open-source storage format that runs on top of existing data lakes. Delta Lake is compatible with processing engines like Apache Spark and provides benefits such as ACID transaction guarantees, schema enforcement, and scalable data handling.

The Delta Lake project aims to unlock the power of the Deltalake for as many users and projects as possible
by providing native low-level APIs aimed at developers and integrators, as well as a high-level operations
API that lets you query, inspect, and operate your Delta Lake with ease.

| Source                  | Downloads                         | Installation Command    | Docs            |
| ----------------------- | --------------------------------- | ----------------------- | --------------- |
| **[PyPi][pypi]**        | [![Downloads][pypi-dl]][pypi]     | `pip install deltalake` | [Docs][py-docs] |
| **[Crates.io][crates]** | [![Downloads][crates-dl]][crates] | `cargo add deltalake`   | [Docs][rs-docs] |

[pypi]: https://pypi.org/project/deltalake/
[pypi-dl]: https://img.shields.io/pypi/dm/deltalake?style=flat-square&color=00ADD4
[py-docs]: https://delta-io.github.io/delta-rs/
[rs-docs]: https://docs.rs/deltalake/latest/deltalake/
[crates]: https://crates.io/crates/deltalake
[crates-dl]: https://img.shields.io/crates/d/deltalake?color=F75101

## Table of contents

- [Table of contents](#table-of-contents)
- [Quick Start](#quick-start)
- [Get Involved](#get-involved)
- [Integrations](#integrations)
- [Features](#features)
  - [Cloud Integrations](#cloud-integrations)
  - [Supported Operations](#supported-operations)
  - [Protocol Support Level](#protocol-support-level)

## Quick Start

The `deltalake` library aims to adopt patterns from other libraries in data processing,
so getting started should look familiar.

```py3
from deltalake import DeltaTable, write_deltalake
import pandas as pd

# write some data into a delta table
df = pd.DataFrame({"id": [1, 2], "value": ["foo", "boo"]})
write_deltalake("./data/delta", df)

# Load data from the delta table
dt = DeltaTable("./data/delta")
df2 = dt.to_pandas()

assert df.equals(df2)
```

The same table can also be loaded using the core Rust crate:

```rs
use deltalake::{open_table, DeltaTableError};

#[tokio::main]
async fn main() -> Result<(), DeltaTableError> {
    // open the table written in python
    let table = open_table("./data/delta").await?;

    // show all active files in the table
    let files: Vec<_> = table.get_file_uris()?.collect();
    println!("{files:?}");

    Ok(())
}
```

You can also try Delta Lake docker at [DockerHub](https://go.delta.io/dockerhub) | [Docker Repo](https://go.delta.io/docker)

## Get Involved

We encourage you to reach out, and are [committed](https://github.com/delta-io/delta-rs/blob/main/CODE_OF_CONDUCT.md)
to provide a welcoming community.

- [Join us in our Slack workspace](https://go.delta.io/slack)
- [Report an issue](https://github.com/delta-io/delta-rs/issues/new?template=bug_report.md)
- Looking to contribute? See our [good first issues](https://github.com/delta-io/delta-rs/contribute).

## Integrations

Libraries and frameworks that interoperate with delta-rs - in alphabetical order.

- [AWS SDK for Pandas](https://github.com/aws/aws-sdk-pandas)
- [ballista][ballista]
- [datafusion][datafusion]
- [Daft](https://www.getdaft.io/)
- [Dask](https://github.com/dask-contrib/dask-deltatable)
- [datahub](https://datahubproject.io/)
- [DuckDB](https://duckdb.org/)
- [polars](https://www.pola.rs/)
- [Ray](https://github.com/delta-incubator/deltaray)

## Features

The following section outlines some core features like supported [storage backends](#cloud-integrations)
and [operations](#supported-operations) that can be performed against tables. The state of implementation
of features outlined in the Delta [protocol][protocol] is also [tracked](#protocol-support-level).

### Cloud Integrations

| Storage              |  Rust   | Python  | Comment                                                          |
| -------------------- | :-----: | :-----: | ---------------------------------------------------------------- |
| Local                | ![done] | ![done] |                                                                  |
| S3 - AWS             | ![done] | ![done] |                                                                  |
| S3 - MinIO           | ![done] | ![done] |                                                                  |
| S3 - R2              | ![done] | ![done] |                                                                  |
| Azure Blob           | ![done] | ![done] |                                                                  |
| Azure ADLS Gen2      | ![done] | ![done] |                                                                  |
| Microsoft OneLake    | ![done] | ![done] |                                                                  |
| Google Cloud Storage | ![done] | ![done] |                                                                  |
| HDFS                 | ![done] | ![done] |                                                                  |
| LakeFS               | ![done] | ![done] |                                                                  |

### Supported Operations

| Operation             |  Rust   | Python  | Description                                 |
| --------------------- | :-----: | :-----: | ------------------------------------------- |
| Create                | ![done] | ![done] | Create a new table                          |
| Read                  | ![done] | ![done] | Read data from a table                      |
| Vacuum                | ![done] | ![done] | Remove unused files and log entries         |
| Delete - predicates   | ![done] | ![done] | Delete data based on a predicate            |
| Optimize - compaction | ![done] | ![done] | Harmonize the size of data file             |
| Optimize - Z-order    | ![done] | ![done] | Place similar data into the same file       |
| Merge                 | ![done] | ![done] | Merge a target Delta table with source data |
| Update                | ![done] | ![done] | Update values from a table                  |
| Add Column            | ![done] | ![done] | Add new columns or nested fields            |
| Add Feature           | ![done] | ![done] | Enable delta table features                 |
| Add Constraints       | ![done] | ![done] | Set delta constraints, to verify data on write |
| Drop Constraints      | ![done] | ![done] | Removes delta constraints                   |
| Set Table Properties  | ![done] | ![done] | Set delta table properties                  |
| Convert to Delta      | ![done] | ![done] | Convert parquet table to delta table        |
| FS check              | ![done] | ![done] | Remove corrupted files from table           |
| Restore               | ![done] | ![done] | Restores table to previous version state    |

### Protocol Support Level

| Writer Version | Requirement                                   |              Status               |
| -------------- | --------------------------------------------- | :-------------------------------: |
| Version 2      | Append Only Tables                            |              ![done]              |
| Version 2      | Column Invariants                             |              ![done]              |
| Version 3      | Enforce `delta.checkpoint.writeStatsAsJson`   |              ![done]              |
| Version 3      | Enforce `delta.checkpoint.writeStatsAsStruct` |              ![done]              |
| Version 3      | CHECK constraints                             | [![done]][check-constraints]      |
| Version 4      | Change Data Feed                              |              ![done]              |
| Version 4      | Generated Columns                             |              ![done]              |
| Version 5      | Column Mapping                                |                                   |
| Version 6      | Identity Columns                              |                                   |
| Version 7      | Table Features                                |              ![done]              |

| Reader Version | Requirement                         |   Status   |
| -------------- | ----------------------------------- |   ------   |
| Version 2      | Column Mapping                      |            |
| Version 3      | Table Features (requires reader V7) |  ![done]   |

[datafusion]: https://github.com/apache/datafusion
[ballista]: https://github.com/apache/arrow-ballista
[polars]: https://github.com/pola-rs/polars
[open]: https://cdn.jsdelivr.net/gh/Readme-Workflows/Readme-Icons@main/icons/octicons/IssueNeutral.svg
[semi-done]: https://cdn.jsdelivr.net/gh/Readme-Workflows/Readme-Icons@main/icons/octicons/ApprovedChangesGrey.svg
[done]: https://cdn.jsdelivr.net/gh/Readme-Workflows/Readme-Icons@main/icons/octicons/ApprovedChanges.svg
[roadmap]: https://github.com/delta-io/delta-rs/issues/1128
[writer-rs]: https://github.com/delta-io/delta-rs/issues/851
[check-constraints]: https://github.com/delta-io/delta-rs/issues/1881
[onelake-rs]: https://github.com/delta-io/delta-rs/issues/1418
[protocol]: https://github.com/delta-io/delta/blob/master/PROTOCOL.md
