apache/shardingsphere · error · SQLFeatureNotSupportedException

getNCharacterStream

Error message

getNCharacterStream

What it means

getNCharacterStream(int columnIndex) is final in AbstractUnsupportedOperationResultSet and always throws SQLFeatureNotSupportedException. The sharding driver does not expose national-character columns through the N-specific streaming accessor on its merged ResultSet.

Source

Thrown at jdbc/src/main/java/org/apache/shardingsphere/driver/jdbc/unsupported/AbstractUnsupportedOperationResultSet.java:165

    
    @Override
    public final int getHoldability() throws SQLException {
        throw new SQLFeatureNotSupportedException("getHoldability");
    }
    
    @Override
    public final NClob getNClob(final int columnIndex) throws SQLException {
        throw new SQLFeatureNotSupportedException("getNClob");
    }
    
    @Override
    public final NClob getNClob(final String columnLabel) throws SQLException {
        throw new SQLFeatureNotSupportedException("getNClob");
    }
    
    @Override
    public final Reader getNCharacterStream(final int columnIndex) throws SQLException {
        throw new SQLFeatureNotSupportedException("getNCharacterStream");
    }
    
    @Override
    public final Reader getNCharacterStream(final String columnLabel) throws SQLException {
        throw new SQLFeatureNotSupportedException("getNCharacterStream");
    }
    
    @Override
    public final Ref getRef(final int columnIndex) throws SQLException {
        throw new SQLFeatureNotSupportedException("getRef");
    }
    
    @Override
    public final Ref getRef(final String columnLabel) throws SQLException {
        throw new SQLFeatureNotSupportedException("getRef");
    }
    
    @Override

View on GitHub (pinned to e952770a21)

Solutions

1. Use getCharacterStream(columnIndex) (or getString) instead — the regular character stream accessor is supported and returns the same text.
2. Wrap the returned Reader for your streaming pipeline; for repeated small reads, getString is simpler.
3. Update mapper type handlers to prefer non-N accessors under this driver.

Example fix

// before
Reader reader = rs.getNCharacterStream(3); // throws

// after
Reader reader = rs.getCharacterStream(3);

Reader reader = rs.getCharacterStream(col); // same text, supported accessor

try {
    reader = rs.getNCharacterStream(col);
} catch (SQLFeatureNotSupportedException e) {
    reader = rs.getCharacterStream(col);
}

When it happens

Trigger: Calling ResultSet.getNCharacterStream(columnIndex) on a ResultSet from ShardingSphereDataSource — usually in streaming readers for large NCHAR/NVARCHAR/NCLOB data or type-dispatching row mappers.

Common situations: Large national-character column handling written against Oracle/SQL Server drivers; common-dbutils/ORM type handlers that pick getNCharacterStream for Types.NCLOB/NVARCHAR; migration to the sharding URL without auditing N-accessor usage.

Related errors

• getNClob
• setNCharacterStream
• updateRow
• deleteRow
• refreshRow

AI-assisted analysis of apache/shardingsphere@e952770a21 (2026-08-14). Data as JSON: /api/errors/b27f1a0321be518e. Report an issue: GitHub.