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/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later.
* See the lgpl.txt file in the root directory or .
*/
package org.hibernate.hql.internal.ast.exec;
import antlr.RecognitionException;
import org.hibernate.AssertionFailure;
import org.hibernate.HibernateException;
import org.hibernate.dialect.Dialect;
import org.hibernate.dialect.MySQLDialect;
import org.hibernate.hql.internal.ast.HqlSqlWalker;
import org.hibernate.hql.internal.ast.QuerySyntaxException;
import org.hibernate.hql.internal.ast.SqlGenerator;
import org.hibernate.hql.internal.ast.tree.AssignmentSpecification;
import org.hibernate.hql.internal.ast.tree.UpdateStatement;
import org.hibernate.param.ParameterSpecification;
import org.hibernate.persister.entity.Queryable;
import org.hibernate.sql.Update;
import java.util.List;
import java.util.stream.IntStream;
import static org.hibernate.hql.spi.id.AbstractTableBasedBulkIdHandler.generateIdSelect;
/**
* Executes HQL bulk updates against a single table, using a subselect
* against multiple tables to collect ids, which is needed when the
* where condition of the query touches columns from multiple tables.
*
* @author Gavin King
*/
public class IdSubselectUpdateExecutor extends BasicExecutor {
private final Queryable persister;
private final String sql;
private final List parameterSpecifications;
public Queryable getPersister() {
return persister;
}
@Override
public String getSql() {
return sql;
}
@Override
public List getParameterSpecifications() {
return parameterSpecifications;
}
public IdSubselectUpdateExecutor(HqlSqlWalker walker) {
persister = walker.getFinalFromClause().getFromElement().getQueryable();
Dialect dialect = walker.getDialect();
UpdateStatement updateStatement = (UpdateStatement) walker.getAST();
List assignments = walker.getAssignmentSpecifications();
String whereClause;
if ( updateStatement.getWhereClause().getNumberOfChildren() == 0 ) {
whereClause = "";
}
else {
try {
SqlGenerator gen = new SqlGenerator( walker.getSessionFactoryHelper().getFactory() );
gen.whereClause( updateStatement.getWhereClause() );
gen.getParseErrorHandler().throwQueryException();
whereClause = gen.getSQL().substring( 7 ); // strip the " where "
}
catch ( RecognitionException e ) {
throw new HibernateException( "Unable to generate id select for DML operation", e );
}
}
String tableAlias = updateStatement.getFromClause().getFromElement().getTableAlias();
String idSelect = generateIdSelect( tableAlias, whereClause, dialect, persister );
String[] tableNames = persister.getConstraintOrderedTableNameClosure();
String[][] columnNames = persister.getContraintOrderedTableKeyColumnClosure();
int[] affectedTables =
IntStream.range( 0, tableNames.length ).filter(
table -> assignments.stream().anyMatch(
assign -> assign.affectsTable( tableNames[table] )
)
).toArray();
if ( affectedTables.length > 1 ) {
throw new AssertionFailure("more than one affected table");
}
int affectedTable = affectedTables[0];
String tableName = tableNames[affectedTable];
String idColumnNames = String.join( ", ", columnNames[affectedTable] );
Update update = new Update( dialect ).setTableName( tableName );
if ( dialect instanceof MySQLDialect) {
//MySQL needs an extra subselect to hack the query optimizer
String selectedIdColumns = String.join( ", ", persister.getIdentifierColumnNames() );
update.setWhere( "(" + idColumnNames + ") in (select " + selectedIdColumns + " from (" + idSelect + ") as ht_ids)" );
}
else {
update.setWhere( "(" + idColumnNames + ") in (" + idSelect + ")" );
}
for ( AssignmentSpecification assignment: assignments ) {
update.appendAssignmentFragment( assignment.getSqlAssignmentFragment() );
}
sql = update.toStatementString();
// now collect the parameters from the whole query
// parameters included in the list
try {
SqlGenerator gen = new SqlGenerator( walker.getSessionFactoryHelper().getFactory() );
gen.statement( walker.getAST() );
parameterSpecifications = gen.getCollectedParameters();
}
catch ( RecognitionException e ) {
throw QuerySyntaxException.convert( e );
}
}
}