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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 table = CreateBuilder::new()
    .with_location(path)
    .with_table_name("/tmp/some-table")
    .with_save_mode(SaveMode::Overwrite)
    .with_columns(
        StructType::try_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?;

use arrow_schema::{Field, Schema, DataType as ArrowDataType};
let data = RecordBatch::try_new(
    Arc::new(Schema::new(vec![
        Field::new("num", ArrowDataType::Int32, true),
        Field::new("letter", ArrowDataType::Utf8, true),
    ])),
    vec![
        Arc::new(arrow::array::Int32Array::from(vec![1, 2, 3])),
        Arc::new(arrow::array::StringArray::from(vec!["a", "b", "c"])),
    ],
)?;

table
    .write(vec![data])
    .with_save_mode(SaveMode::Overwrite)
    .await?;

Here are the contents of the Delta table in storage:

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