Skip to content

Creating a Delta Lake Table

This section explains how to create a Delta Lake table.

You can easily write a DataFrame to a Delta table.

from deltalake import write_deltalake
import pandas as pd

df = pd.DataFrame({"num": [1, 2, 3], "letter": ["a", "b", "c"]})
write_deltalake("tmp/some-table", df)

import polars as pl

df = pl.DataFrame({"num": [1, 2, 3], "letter": ["a", "b", "c"]})
df.write_delta("tmp/some-table")

let delta_ops = DeltaOps::try_from_uri("tmp/some-table").await?;
let mut table = delta_ops
    .create()
    .with_table_name("some-table")
    .with_save_mode(SaveMode::Overwrite)
    .with_columns(
        StructType::new(vec![
            StructField::new(
                "num".to_string(),
                DataType::Primitive(PrimitiveType::Integer),
                true,
            ),
            StructField::new(
                "letter".to_string(),
                DataType::Primitive(PrimitiveType::String),
                true,
            ),
        ])
        .fields()
        .cloned(),
    )
    .await?;

let mut record_batch_writer =
    deltalake::writer::RecordBatchWriter::for_table(&mut table)?;
record_batch_writer
    .write(
        RecordBatch::try_new(
            Arc::new(Schema::new(vec![
                Field::new("num", DataType::Int32, true),
                Field::new("letter", Utf8, true),
            ])),
            vec![
                Arc::new(Int32Array::from(vec![1, 2, 3])),
                Arc::new(StringArray::from(vec![
                    "a", "b", "c",
                ])),
            ],
        )?,
    )
    .await?;
record_batch_writer.flush_and_commit(&mut table).await?;

Here are the contents of the Delta table in storage:

+-------+----------+
|   num | letter   |
|-------+----------|
|     1 | a        |
|     2 | b        |
|     3 | c        |
+-------+----------+