RheaDB

A simple disk-based DBMS that supports simple SQL-like querying statements.

What's currently implemented?

• Simple SQL-like queries
  • Creating & dropping tables
  • Deleting from tables
  • Updating tables
  • Simple selection queries
  • Creating & deleting indices
• Disk-based storage
• In-memory buffer pool caching
• JDBC driver
• B+Tree indexing

Performance test suite

The repository includes a dedicated performance suite in test/performance/RheaDBPerformanceTest.java.

The suite is intentionally gated behind the JVM system property rheadb.perf=true so it does not slow down the normal unit-test cycle.

Running it in IntelliJ

Create or edit a JUnit run configuration for RheaDBPerformanceTest and add:

-Drheadb.perf=true

JDBC driver loading and usage

The connection url passed to DriverManager.getConnection() must be in the format jdbc:rhea:DIR_PATH, where DIR_PATH is the storage directory for the database. The directory will be created if it does not exist.

Class.forName("RheaDB.JDBCDriver.JCDriver") must be used so as to invoke the static portion of the driver, and (hopefully) successfully connect to a database instance.

import java.sql.DriverManager;

public class RheaDBJDBCTest {
    public static void main(String[] args) throws Exception {
        Class.forName("RheaDB.JDBCDriver.JCDriver");
        try (var c = DriverManager.getConnection("jdbc:rhea:./dbdata");
             var s = c.createStatement()) {

            s.execute("CREATE TABLE Planets (ord INT, name STRING, mass FLOAT);");
            s.execute("INSERT INTO Planets VALUES (1, \"Mercury\", 0.328);");
            s.execute("INSERT INTO Planets VALUES (2, \"Venus\", 4.867);");
            s.execute("INSERT INTO Planets VALUES (3, \"Earth\", 5.972);");

            try (var rs = s.executeQuery("SELECT * FROM Planets;")) {
                while (rs.next())
                    System.out.println(rs.getInt(0) + ", " + rs.getString(1) + ", " + rs.getFloat(2));
            }
        }
    }
}

This will create a database in the ./dbdata directory, create a table named Planets, insert some data into it, and then select and print that data.

1, Mercury, 0.328
2, Venus, 4.867
3, Earth, 5.972