/*
* Copyright 2004-2011 H2 Group. Multiple-Licensed under the H2 License,
* Version 1.0, and under the Eclipse Public License, Version 1.0
* (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.command.ddl;
import java.util.ArrayList;
import org.h2.command.CommandInterface;
import org.h2.constant.ErrorCode;
import org.h2.constraint.ConstraintReferential;
import org.h2.engine.Database;
import org.h2.engine.Right;
import org.h2.engine.Session;
import org.h2.message.DbException;
import org.h2.schema.Schema;
import org.h2.table.Table;
import org.h2.table.TableView;
import org.h2.util.StatementBuilder;
/**
* This class represents the statement
* DROP TABLE
*/
public class DropTable extends SchemaCommand {
private boolean ifExists;
private String tableName;
private Table table;
private DropTable next;
private int dropAction;
public DropTable(Session session, Schema schema) {
super(session, schema);
dropAction = session.getDatabase().getSettings().dropRestrict ?
ConstraintReferential.RESTRICT :
ConstraintReferential.CASCADE;
}
/**
* Chain another drop table statement to this statement.
*
* @param drop the statement to add
*/
public void addNextDropTable(DropTable drop) {
if (next == null) {
next = drop;
} else {
next.addNextDropTable(drop);
}
}
public void setIfExists(boolean b) {
ifExists = b;
if (next != null) {
next.setIfExists(b);
}
}
public void setTableName(String tableName) {
this.tableName = tableName;
}
private void prepareDrop() {
table = getSchema().findTableOrView(session, tableName);
if (table == null) {
if (!ifExists) {
throw DbException.get(ErrorCode.TABLE_OR_VIEW_NOT_FOUND_1, tableName);
}
} else {
session.getUser().checkRight(table, Right.ALL);
if (!table.canDrop()) {
throw DbException.get(ErrorCode.CANNOT_DROP_TABLE_1, tableName);
}
if (dropAction == ConstraintReferential.RESTRICT) {
ArrayList<TableView> views = table.getViews();
if (views != null && views.size() > 0) {
StatementBuilder buff = new StatementBuilder();
for (TableView v : views) {
buff.appendExceptFirst(", ");
buff.append(v.getName());
}
throw DbException.get(ErrorCode.CANNOT_DROP_2, tableName, buff.toString());
}
}
table.lock(session, true, true);
}
if (next != null) {
next.prepareDrop();
}
}
private void executeDrop() {
// need to get the table again, because it may be dropped already
// meanwhile (dependent object, or same object)
table = getSchema().findTableOrView(session, tableName);
if (table != null) {
table.setModified();
Database db = session.getDatabase();
db.removeSchemaObject(session, table);
}
if (next != null) {
next.executeDrop();
}
}
public int update() {
session.commit(true);
prepareDrop();
executeDrop();
return 0;
}
public void setDropAction(int dropAction) {
this.dropAction = dropAction;
if (next != null) {
next.setDropAction(dropAction);
}
}
public int getType() {
return CommandInterface.DROP_TABLE;
}
}