/*
* Copyright 2004-2023 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.table;
import java.util.ArrayList;
import org.h2.api.ErrorCode;
import org.h2.command.query.Query;
import org.h2.engine.SessionLocal;
import org.h2.expression.ExpressionVisitor;
import org.h2.expression.Parameter;
import org.h2.index.QueryExpressionIndex;
import org.h2.message.DbException;
import org.h2.util.StringUtils;
/**
* A derived table.
*/
public final class DerivedTable extends QueryExpressionTable {
private String querySQL;
private Query topQuery;
/**
* Create a derived table out of the given query.
*
* @param session the session
* @param name the view name
* @param columnTemplates column templates, or {@code null}
* @param query the initialized query
* @param topQuery the top level query
*/
public DerivedTable(SessionLocal session, String name, Column[] columnTemplates, Query query, Query topQuery) {
super(session.getDatabase().getMainSchema(), 0, name);
setTemporary(true);
this.topQuery = topQuery;
query.prepareExpressions();
try {
this.querySQL = query.getPlanSQL(DEFAULT_SQL_FLAGS);
ArrayList<Parameter> params = query.getParameters();
index = new QueryExpressionIndex(this, querySQL, params, false);
tables = new ArrayList<>(query.getTables());
setColumns(initColumns(session, columnTemplates, query, true));
viewQuery = query;
} catch (DbException e) {
if (e.getErrorCode() == ErrorCode.COLUMN_ALIAS_IS_NOT_SPECIFIED_1) {
throw e;
}
e.addSQL(getCreateSQL());
throw e;
}
}
@Override
public boolean isQueryComparable() {
if (!super.isQueryComparable()) {
return false;
}
if (topQuery != null && !topQuery.isEverything(ExpressionVisitor.QUERY_COMPARABLE_VISITOR)) {
return false;
}
return true;
}
@Override
public boolean canDrop() {
return false;
}
@Override
public TableType getTableType() {
return null;
}
@Override
public Query getTopQuery() {
return topQuery;
}
@Override
public String getCreateSQL() {
return null;
}
@Override
public StringBuilder getSQL(StringBuilder builder, int sqlFlags) {
return StringUtils.indent(builder.append("( "), querySQL, 4, true).append(')');
}
}