duckdb 0.1.0

d-duckdb

DuckDB client for D. This client is based on DuckDB's C API.

Usage

Iterate query result via foreach

import duckdb;
import std;

void main()
{
    auto db = new Database(null);  // null for in-memory database
    auto conn = db.connect();

    writeln(duckdbVersion);

    conn.queryWithoutResult("CREATE TABLE integers (i INTEGER, j INTEGER);");
    conn.queryWithoutResult("INSERT INTO integers VALUES (3, 4), (5, 6), (7, NULL);");
    auto r = conn.query("SELECT * FROM integers;");
    foreach (int a, Nullable!int b; r)  // Specify argument types explicitly
        writeln(a, ", ",  b);

    conn.disconnect();
    db.close();
}

Appender: Faster bulk insertion

import duckdb;
import std;

void main()
{
    auto db = new Database(null);  // null for in-memory database
    auto conn = db.connect();

    writeln(duckdbVersion);
    conn.queryWithoutResult("CREATE TABLE apps (i SMALLINT, str VARCHAR, ts TIMESTAMP);");
    auto appender = conn.appender("apps");
    foreach (i; 0..3)
        appender.appendRow(i, text("Name", i), Clock.currTime);
    appender.destroy();

    auto r = conn.query("SELECT * FROM apps;");
    foreach (short i, string str, SysTime ts; r)
        writeln("id: ", i, ", name: ", str, ", timestampe: ", ts);
    r.destroy();

    conn.disconnect();
    db.close();
}

DuckDB and D Types

Special cases

• NULL

Use std.typecons.Nullable to accept NULL for basic types, e.g. Nullable!int. Without Nullable, client returns .init value.

• Infinity for DATA and TIMESTAMP

Infinity/-Infinity is mapping to .init value, e.g. Date.init and SysTime.init.

TODO

• Support TODO DuckDB types
• Support more APIs
• Prepared Statements
• and more
• Improve API design
• Add unittests

Links

• DuckDB – An in-process SQL OLAP database management system

DuckDB official site

• Overview – DuckDB

DuckDB C API document

Copyright

Copyright (c) 2024- Masahiro Nakagawa

License

Distributed under the Boost Software License, Version 1.0.