README.md

chdb Java FFM binding

chdb-java-ffm is Java 22+ JEP 454: Foreign Function & Memory API bind for chdb.

Get started

• Please add the following dependency to pom.xml:

<dependency>
    <groupId>org.mvnsearch</groupId>
    <artifactId>chdb-java-ffm</artifactId>
    <version>0.2.0</version>
</dependency>

• Download chdb dynamic library by executing update_libchdb.sh script, or download from https://github.com/chdb-io/chdb/releases.
• Write your first test:

public class ChdbConnectionTest {

    @AutoClose
    private static Connection conn;

    @BeforeAll
    public static void setUp() throws Exception {
        String url = "jdbc:chdb::memory:";
        conn = DriverManager.getConnection(url);
    }

    @Test
    public void testConnection() throws SQLException {
        String sql = "select * from file('src/test/resources/logs.csv','CSV')";
        Statement statement = conn.createStatement();
        ResultSet resultSet = statement.executeQuery(sql);
        while (resultSet.next()) {
            System.out.println(resultSet.getString("level"));
        }
    }
}

chdb JDBC

JDBC URLs:

• jdbc:chdb::memory:: in-memory database, path is :memory:
• jdbc:chdb:/path/to/db: database from file path, and both relative and absolute paths supported.

Development setup

• Download and install JDK 22
• Download and install jextract
• Execute update_libchdb.sh to download dynamic library

FAQ

How to load dynamic library from other path?

Execute ln -s /usr/local/lib/libchdb.so libchdb.dylib to link the dynamic library to the current directory.

Update operation support?

Now only query support, and update will be implemented in the future.

PreparedStatement support?

Now PreparedStatement implement is not real, just fake implement friendly for libraries and frameworks.

Spring Jdbc support?

Yes, you can use JdbcTemplate with chdb-java-ffm.

How it works?

Java -> FFM -> chdb(embedded) -> JSON Output -> ResultSet.

Attention: chdb-java-ffm uses Jackson for JSON parsing.

References

• JEP 454: Foreign Function & Memory API
• jextract: a tool which mechanically generates Java bindings from native library headers
• chdb-java: chdb JNI version
• clickhouse-java: Java client and JDBC driver for ClickHouse