apache/shardingsphere · error · SQLFeatureNotSupportedException

isSigned

Error message

isSigned

What it means

SQLFeatureNotSupportedException thrown by AbstractUnsupportedOperationParameterMetaData.isSigned(int). ShardingSphere's ParameterMetaData is built purely from the locally parsed SQLStatement (ShardingSphereParameterMetaData only implements getParameterCount()); signedness of a '?' placeholder is not representable without backend type info, so the method is final and always throws.

Source

Thrown at jdbc/src/main/java/org/apache/shardingsphere/driver/jdbc/unsupported/AbstractUnsupportedOperationParameterMetaData.java:38

import org.apache.shardingsphere.driver.jdbc.adapter.WrapperAdapter;

import java.sql.ParameterMetaData;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;

/**
 * Unsupported {@code ParameterMetaData} methods.
 */
public abstract class AbstractUnsupportedOperationParameterMetaData extends WrapperAdapter implements ParameterMetaData {
    
    @Override
    public final int isNullable(final int parameter) throws SQLException {
        throw new SQLFeatureNotSupportedException("isNullable");
    }
    
    @Override
    public final boolean isSigned(final int parameter) throws SQLException {
        throw new SQLFeatureNotSupportedException("isSigned");
    }
    
    @Override
    public final int getPrecision(final int parameter) throws SQLException {
        throw new SQLFeatureNotSupportedException("getPrecision");
    }
    
    @Override
    public final int getScale(final int parameter) throws SQLException {
        throw new SQLFeatureNotSupportedException("getScale");
    }
    
    @Override
    public final int getParameterType(final int parameter) throws SQLException {
        throw new SQLFeatureNotSupportedException("getParameterType");
    }
    
    @Override

View on GitHub (pinned to e952770a21)

Solutions

1. Remove the isSigned probe when running against ShardingSphere; bind values with setBigDecimal/setLong which ignore signedness.
2. If sign matters, read it from DatabaseMetaData.getColumns of the underlying database instead of ParameterMetaData.
3. Catch SQLFeatureNotSupportedException first and treat the parameter as signed-unknown (true is the safe default for numeric binding).

Example fix

// before
boolean signed = pmd.isSigned(1);

// after
boolean signed = true; // assume signed; ShardingSphere ParameterMetaData cannot report it

if (!conn.getMetaData().getDriverName().toLowerCase().contains("shardingsphere")) { boolean s = pmd.isSigned(1); }

static boolean reportsParameterSign(final ParameterMetaData pmd) {
    try { pmd.isSigned(1); return true; } catch (final SQLFeatureNotSupportedException e) { return false; }
}

try {
    signed = pmd.isSigned(1);
} catch (final SQLFeatureNotSupportedException e) {
    signed = true; // safe default for numeric binding
}

When it happens

Trigger: Calling ps.getParameterMetaData().isSigned(i) on a jdbc:shardingsphere: PreparedStatement. Typical offenders: schema-inspection utilities, JDBC 4 compliance test suites, and frameworks that pick numeric setters based on signedness.

Common situations: Generic ORM/repositories or reporting engines migrated onto sharding-jdbc; SQLServer/Oracle to ShardingSphere driver swaps where the old driver answered isSigned; automated DB-compat test suites failing only on sharded datasources.

Related errors

• isNullable
• getPrecision
• getScale
• getParameterType
• getParameterTypeName

AI-assisted analysis of apache/shardingsphere@e952770a21 (2026-08-14). Data as JSON: /api/errors/f54bdc244778fa10. Report an issue: GitHub.