add readme

README.md

@@ -1,2 +1,92 @@
 # airflow-provider-duckdb
-A provider package for DuckDB
+
+A DuckDB provider for Airflow. This provider exposes a hook/connection that returns a DuckDB connection.
+
+## Installation
+
+```bash
+pip install apache-airflow-providers-duckdb
+```
+
+## Connection
+
+The connection type is `duckdb`. It supports setting the following parameters:
+
+- `file` (optional): The path to the DuckDB database file. If not set, operations will be done in-memory.
+
+## Usage
+
+```python
+import pandas as pd
+import pendulum
+
+from airflow.decorators import dag, task
+from duckdb_provider.hooks.duckdb_hook import DuckDBHook
+
+
+@dag(
+    schedule=None,
+    start_date=pendulum.datetime(2022, 1, 1, tz="UTC"),
+    catchup=False,
+)
+def duckdb_transform():
+    @task
+    def create_df() -> pd.DataFrame:
+        """
+        Create a dataframe with some sample data
+        """
+        df = pd.DataFrame(
+            {
+                "a": [1, 2, 3],
+                "b": [4, 5, 6],
+                "c": [7, 8, 9],
+            }
+        )
+        return df
+
+    @task
+    def simple_select(df: pd.DataFrame) -> pd.DataFrame:
+        """
+        Use DuckDB to select a subset of the data
+        """
+        hook = DuckDBHook.get_hook('duckdb_default')
+        conn = hook.get_conn()
+
+        # execute a simple query
+        res = conn.execute("SELECT a, b, c FROM df WHERE a >= 2").df()
+
+        return res
+
+    @task
+    def add_col(df: pd.DataFrame) -> pd.DataFrame:
+        """
+        Use DuckDB to add a column to the data
+        """
+        hook = DuckDBHook.get_hook('duckdb_default')
+        conn = hook.get_conn()
+
+        # add a column
+        conn.execute("CREATE TABLE tb AS SELECT *, a + b AS d FROM df")
+
+        # get the table
+        return conn.execute("SELECT * FROM tb").df()
+
+    @task
+    def aggregate(df: pd.DataFrame) -> pd.DataFrame:
+        """
+        Use DuckDB to aggregate the data
+        """
+        hook = DuckDBHook.get_hook('duckdb_default')
+        conn = hook.get_conn()
+
+        # aggregate
+        return conn.execute("SELECT SUM(a), COUNT(b) FROM df").df()
+
+    create_df_res = create_df()
+    simple_select_res = simple_select(create_df_res)
+    add_col_res = add_col(simple_select_res)
+    aggregate_res = aggregate(add_col_res)
+
+
+duckdb_transform()
+```