org.h2.command.ddl.DropView Maven / Gradle / Ivy
/*
* Copyright 2004-2022 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.command.ddl;
import java.util.ArrayList;
import org.h2.api.ErrorCode;
import org.h2.command.CommandInterface;
import org.h2.constraint.ConstraintActionType;
import org.h2.engine.DbObject;
import org.h2.engine.SessionLocal;
import org.h2.message.DbException;
import org.h2.schema.Schema;
import org.h2.table.Table;
import org.h2.table.TableType;
import org.h2.table.TableView;
/**
* This class represents the statement
* DROP VIEW
*/
public class DropView extends SchemaCommand {
private String viewName;
private boolean ifExists;
private ConstraintActionType dropAction;
public DropView(SessionLocal session, Schema schema) {
super(session, schema);
dropAction = session.getDatabase().getSettings().dropRestrict ?
ConstraintActionType.RESTRICT :
ConstraintActionType.CASCADE;
}
public void setIfExists(boolean b) {
ifExists = b;
}
public void setDropAction(ConstraintActionType dropAction) {
this.dropAction = dropAction;
}
public void setViewName(String viewName) {
this.viewName = viewName;
}
@Override
public long update() {
Table view = getSchema().findTableOrView(session, viewName);
if (view == null) {
if (!ifExists) {
throw DbException.get(ErrorCode.VIEW_NOT_FOUND_1, viewName);
}
} else {
if (TableType.VIEW != view.getTableType()) {
throw DbException.get(ErrorCode.VIEW_NOT_FOUND_1, viewName);
}
session.getUser().checkSchemaOwner(view.getSchema());
if (dropAction == ConstraintActionType.RESTRICT) {
for (DbObject child : view.getChildren()) {
if (child instanceof TableView) {
throw DbException.get(ErrorCode.CANNOT_DROP_2, viewName, child.getName());
}
}
}
// TODO: Where is the ConstraintReferential.CASCADE style drop processing ? It's
// supported from imported keys - but not for dependent db objects
TableView tableView = (TableView) view;
ArrayList copyOfDependencies = new ArrayList<>(tableView.getTables());
view.lock(session, Table.EXCLUSIVE_LOCK);
session.getDatabase().removeSchemaObject(session, view);
// remove dependent table expressions
for (Table childTable: copyOfDependencies) {
if (TableType.VIEW == childTable.getTableType()) {
TableView childTableView = (TableView) childTable;
if (childTableView.isTableExpression() && childTableView.getName() != null) {
session.getDatabase().removeSchemaObject(session, childTableView);
}
}
}
// make sure its all unlocked
session.getDatabase().unlockMeta(session);
}
return 0;
}
@Override
public int getType() {
return CommandInterface.DROP_VIEW;
}
}
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