apache/shardingsphere · error · SQLFeatureNotSupportedException

updateNString

Error message

updateNString

What it means

The federation ResultSet returned by ShardingSphere's SQL federation engine overrides every updateXxx method in AbstractUnsupportedUpdateOperationSQLFederationResultSet to throw SQLFeatureNotSupportedException, message 'updateNString' for the national-character-string updater (column-index overload). NString in-place writes are unsupported because the federated result is a read-only, in-memory computed view, not an updatable database cursor.

Source

Thrown at kernel/sql-federation/core/src/main/java/org/apache/shardingsphere/sqlfederation/resultset/AbstractUnsupportedUpdateOperationSQLFederationResultSet.java:144

    
    @Override
    public final void updateBigDecimal(final String columnLabel, final BigDecimal x) throws SQLException {
        throw new SQLFeatureNotSupportedException("updateBigDecimal");
    }
    
    @Override
    public final void updateString(final int columnIndex, final String x) throws SQLException {
        throw new SQLFeatureNotSupportedException("updateString");
    }
    
    @Override
    public final void updateString(final String columnLabel, final String x) throws SQLException {
        throw new SQLFeatureNotSupportedException("updateString");
    }
    
    @Override
    public final void updateNString(final int columnIndex, final String nString) throws SQLException {
        throw new SQLFeatureNotSupportedException("updateNString");
    }
    
    @Override
    public final void updateNString(final String columnLabel, final String nString) throws SQLException {
        throw new SQLFeatureNotSupportedException("updateNString");
    }
    
    @Override
    public final void updateBytes(final int columnIndex, final byte[] x) throws SQLException {
        throw new SQLFeatureNotSupportedException("updateBytes");
    }
    
    @Override
    public final void updateBytes(final String columnLabel, final byte[] x) throws SQLException {
        throw new SQLFeatureNotSupportedException("updateBytes");
    }
    
    @Override

View on GitHub (pinned to e952770a21)

Solutions

1. Read with getNString(columnIndex) and perform writes through a PreparedStatement UPDATE using setNString, keyed on the primary key.
2. Check rs.getConcurrency() before update-cursor code; for read-only concurrency use statement-based writes only.
3. Adjust the sql_federation rule so the statement bypasses federation and returns the backend driver's ResultSet.

Example fix

// before
rs.updateNString(5, "こんにちは");  // SQLFeatureNotSupportedException: updateNString

// after
try (PreparedStatement upd = conn.prepareStatement("UPDATE messages SET body = ? WHERE id = ?")) {
    upd.setNString(1, "こんにちは");
    upd.setLong(2, rs.getLong(1));
    upd.executeUpdate();
}

if (rs.getConcurrency() != ResultSet.CONCUR_UPDATABLE) {
    // rs.updateNString(...) unsupported; use UPDATE + setNString
}

private static boolean supportsRowUpdates(final ResultSet rs) throws SQLException {
    return rs.getConcurrency() == ResultSet.CONCUR_UPDATABLE;
}

try {
    rs.updateNString(5, text);
} catch (final SQLFeatureNotSupportedException ignored) {
    try (PreparedStatement upd = conn.prepareStatement("UPDATE messages SET body = ? WHERE id = ?")) {
        upd.setNString(1, text);
        upd.setLong(2, rs.getLong(1));
        upd.executeUpdate();
    }
}

When it happens

Trigger: Calling ResultSet.updateNString(int columnIndex, String nString) on a federation ResultSet (statement executed via sql_federation, e.g. cross-shard join). Encountered in i18n-heavy applications or generic column writers that handle NVARCHAR/NCHAR via the N-variants of JDBC methods.

Common situations: Code that uniformly uses updateNString for Unicode-safe writes running against a newly federated ShardingSphere datasource; framework migration where NVARCHAR editing code paths receive federation result sets; sqlFederation enabled for queries previously served by the underlying driver's updatable cursor.

Related errors

• updateLong
• updateFloat
• updateDouble
• updateBigDecimal
• updateString

AI-assisted analysis of apache/shardingsphere@e952770a21 (2026-08-14). Data as JSON: /api/errors/5c6d7b87c09fc616. Report an issue: GitHub.