apache/shardingsphere · error · SQLFeatureNotSupportedException

isNullable

Error message

isNullable

What it means

java.sql.SQLFeatureNotSupportedException thrown by ShardingSphere JDBC's AbstractUnsupportedOperationParameterMetaData.isNullable(int). The ShardingSphere driver prepares statements locally (it only parses SQL to route shards), so it never reaches a real backend prepare and cannot know whether a '?' parameter accepts NULL. The concrete ShardingSphereParameterMetaData implements only getParameterCount(); every per-parameter metadata method inherits this final throwing override.

Source

Thrown at jdbc/src/main/java/org/apache/shardingsphere/driver/jdbc/unsupported/AbstractUnsupportedOperationParameterMetaData.java:33

 * limitations under the License.
 */

package org.apache.shardingsphere.driver.jdbc.unsupported;

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

View on GitHub (pinned to e952770a21)

Solutions

1. Do not call ParameterMetaData.isNullable through the ShardingSphere driver; derive nullability from your own domain knowledge of the SQL or from table/column metadata of the underlying database.
2. If you must have per-parameter metadata, execute the statement once and use ResultSetMetaData of the result, or unwrap the real backend PreparedStatement (e.g. via a direct non-sharded DataSource for metadata probes).
3. Catch SQLFeatureNotSupportedException (before the generic SQLException catch) and fall back to ParameterMetaData.parameterNoNulls/parameterNullableUnknown semantics.

Example fix

// before
int nullable = ps.getParameterMetaData().isNullable(1);

// after
int nullable;
try {
    nullable = ps.getParameterMetaData().isNullable(1);
} catch (final SQLFeatureNotSupportedException e) {
    nullable = ParameterMetaData.parameterNullableUnknown; // ShardingSphere cannot know pre-execution
}

// Only getParameterCount() is safe on ShardingSphere ParameterMetaData
boolean isSS;
try { isSS = conn.getMetaData().getDriverName().toLowerCase().contains("shardingsphere"); } catch (SQLException e) { isSS = false; }
if (!isSS) { int n = pmd.isNullable(1); } else { /* skip probe */ }

static boolean isShardingSphereParameterMetaData(final ParameterMetaData pmd) {
    return pmd != null && pmd.getClass().getName().startsWith("org.apache.shardingsphere.driver.jdbc");
}

try {
    int nullable = pmd.isNullable(1);
} catch (final SQLFeatureNotSupportedException e) {
    nullable = ParameterMetaData.parameterNullableUnknown; // catch BEFORE generic SQLException
}

When it happens

Trigger: Calling ((ShardingSpherePreparedStatement) ps).getParameterMetaData().isNullable(paramIndex) on a connection whose URL is jdbc:shardingsphere:... . Any library that probes parameter nullability before binding (report writers, generic query builders, JDBC spec-compliance suites) hits it.

Common situations: Running MyBatis/Hibernate/Jooq-free generic DAO layers, Spring's SqlParameterSource probing, or BI/report tools (JasperReports, BIRT) on top of sharding-jdbc after adding sharding or encrypt rules; also appears when porting an app from MySQL Connector/J (which supports isNullable) to ShardingSphere.

Related errors

• isSigned
• getPrecision
• getScale
• getParameterType
• getParameterTypeName

AI-assisted analysis of apache/shardingsphere@e952770a21 (2026-08-14). Data as JSON: /api/errors/08c28da92a5c73f0. Report an issue: GitHub.