baomidou/mybatis-plus · error · RuntimeException

Unsupported database type: {}

Error message

Unsupported database type: {}

What it means

DdlHelper.newDdlGenerator (the private factory shown) maps the DbType parsed from a JDBC URL to a DDL generator: MySQL family, Oracle family, SQLite, PostgreSQL family. Any other DbType falls through to RuntimeException('Unsupported database type: <jdbcUrl>'). It means you invoked the DDL/dataset-component (e.g. the simple data-script runner) against a database for which no DDL generator ships.

Source

Thrown at mybatis-plus-extension/src/main/java/com/baomidou/mybatisplus/extension/ddl/DdlHelper.java:262

    }

    protected static IDdlGenerator getDdlGenerator(String jdbcUrl) throws RuntimeException {
        DbType dbType = JdbcUtils.getDbType(jdbcUrl);
        // mysql same type
        if (dbType.mysqlSameType()) {
            return MysqlDdlGenerator.newInstance();
        }
        // oracle same type
        else if (dbType.oracleSameType()) {
            return OracleDdlGenerator.newInstance();
        } else if (DbType.SQLITE == dbType) {
            return SQLiteDdlGenerator.newInstance();
        }
        // postgresql same type
        else if (dbType.postgresqlSameType()) {
            return PostgreDdlGenerator.newInstance();
        }
        throw new RuntimeException("Unsupported database type: " + jdbcUrl);
    }

    public static String getDatabase(String jdbcUrl) {
        String[] urlArr = jdbcUrl.split("://");
        if (urlArr.length == 2) {
            String[] dataArr = urlArr[1].split("/");
            if (dataArr.length > 1) {
                return dataArr[1].split("\\?")[0];
            }
        }
        return null;
    }
}

View on GitHub (pinned to bf67d90747)

Solutions

  1. Use one of the supported databases for DDL operations: MySQL-family, Oracle-family, SQLite, or PostgreSQL-family.
  2. If you must target an unsupported DB, run your DDL scripts through that database's native tooling or plain JDBC ScriptRunner instead of DdlHelper.
  3. Check the DbType detection of your JDBC URL (DbType.getDbType(url)) to confirm which branch is (not) taken.
  4. Contribute or extend with a custom DdlGenerator if you depend on this API long-term.

Example fix

// before: H2 test URL -> RuntimeException('Unsupported database type')
String url = "jdbc:h2:mem:test";
try (Connection c = DdlHelper.getSimpleConnection(driver, url, u, p)) { ... }

// after: run DDL over plain JDBC for unsupported DBs
try (Connection c = DriverManager.getConnection(url, u, p);
     Statement st = c.createStatement()) {
    st.execute("CREATE TABLE t (id BIGINT PRIMARY KEY)");
}
Defensive patterns

Strategy: validation

Validate before calling

DbType dbType = DbType.getDbType(jdbcUrl);
boolean ddlSupported = dbType.mysqlSameType() || dbType.oracleSameType()
    || DbType.SQLITE == dbType || dbType.postgresqlSameType();
if (!ddlSupported) throw new UnsupportedOperationException("DDL helper unsupported for " + dbType);

Type guard

static boolean supportsDdlHelper(DbType t) {
    return t.mysqlSameType() || t.oracleSameType()
        || t.postgresqlSameType() || DbType.SQLITE == t;
}

Try / catch

try {
    generator = DdlHelper.newDdlGenerator(driver, url, u, p);
} catch (RuntimeException e) {
    if (String.valueOf(e.getMessage()).startsWith("Unsupported database type")) {
        // route to plain JDBC script execution instead
    } else throw e;
}

Prevention

When it happens

Trigger: Calling DdlHelper-based APIs (getSimpleConnection, newDdlGenerator — used by the extension's DDL application/dataset module) while connected to H2, SQL Server, DM, Kingbase, ClickHouse, MariaDB-with-unrecognized-URL, or any DbType outside the four supported families.

Common situations: Using the DDL helper during local tests on H2; pointing the tool at SQL Server or a Chinese domestic database (DM/OceanBase/Gauss) that is not in the generator map; a JDBC URL whose DbType detection resolves to something unexpected.

Related errors

AI-assisted analysis of baomidou/mybatis-plus@bf67d90747 (2026-08-14). Data as JSON: /api/errors/61b4b4ab3d1dc909. Report an issue: GitHub.