Connections & Transactions

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DuckdbEx exposes a connection API similar to duckdb-python.

Connect

{:ok, conn} = DuckdbEx.Connection.connect(:memory)
{:ok, conn} = DuckdbEx.Connection.connect("/tmp/app.duckdb")

Default connection:

{:ok, _} = DuckdbEx.execute("SELECT 1")
{:ok, rows} = DuckdbEx.fetchall()

Execute & Fetch

execute/3 returns the connection. Use execute_result/3 or fetch_* to read results.

{:ok, conn} = DuckdbEx.Connection.execute(conn, "CREATE TABLE t (id INT)")
{:ok, result} = DuckdbEx.Connection.execute_result(conn, "SELECT 1 AS id")
rows = DuckdbEx.Result.fetch_all(result)
# rows == [{1}]

Parameter Binding

Supported styles:

DuckdbEx.Connection.execute(conn, "SELECT ?::INTEGER", [42])
DuckdbEx.Connection.execute(conn, "SELECT $1::INTEGER", [42])
DuckdbEx.Connection.execute(conn, "SELECT :id::INTEGER", %{id: 42})

executemany

DuckdbEx.Connection.executemany(conn, "INSERT INTO t VALUES (?)", [[1], [2], [3]])

Cursors & Duplicates

cursor/1 and duplicate/1 return a lightweight cursor wrapper. Closing a cursor does not close the underlying connection.

{:ok, cursor} = DuckdbEx.Connection.cursor(conn)
DuckdbEx.Connection.close(cursor)

Transactions

DuckdbEx.Connection.begin(conn)
DuckdbEx.Connection.execute(conn, "INSERT INTO t VALUES (1)")
DuckdbEx.Connection.commit(conn)

DuckdbEx.Connection.transaction(conn, fn tx_conn ->
  DuckdbEx.Connection.execute(tx_conn, "INSERT INTO t VALUES (2)")
end)

Description & Rowcount

DuckdbEx.Connection.execute(conn, "SELECT 42 AS answer")
{:ok, description} = DuckdbEx.Connection.description(conn)
rowcount = DuckdbEx.Connection.rowcount(conn)