/*
Derby - Class org.apache.derby.impl.sql.execute.DropViewConstantAction
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to you under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package org.apache.derby.impl.sql.execute;
import org.apache.derby.iapi.error.StandardException;
import org.apache.derby.iapi.reference.SQLState;
import org.apache.derby.iapi.services.sanity.SanityManager;
import org.apache.derby.iapi.sql.Activation;
import org.apache.derby.iapi.sql.conn.LanguageConnectionContext;
import org.apache.derby.iapi.sql.depend.DependencyManager;
import org.apache.derby.iapi.sql.dictionary.DataDictionary;
import org.apache.derby.iapi.sql.dictionary.SchemaDescriptor;
import org.apache.derby.iapi.sql.dictionary.TableDescriptor;
import org.apache.derby.iapi.sql.dictionary.ViewDescriptor;
import org.apache.derby.iapi.sql.execute.ConstantAction;
import org.apache.derby.iapi.store.access.TransactionController;
/**
* This class describes actions that are ALWAYS performed for a
* DROP VIEW Statement at Execution time.
*
*/
class DropViewConstantAction extends DDLConstantAction
{
private String fullTableName;
private String tableName;
private SchemaDescriptor sd;
// CONSTRUCTORS
/**
* Make the ConstantAction for a DROP VIEW statement.
*
*
* @param fullTableName Fully qualified table name
* @param tableName Table name.
* @param sd Schema that view lives in.
*
*/
DropViewConstantAction(
String fullTableName,
String tableName,
SchemaDescriptor sd )
{
this.fullTableName = fullTableName;
this.tableName = tableName;
this.sd = sd;
if (SanityManager.DEBUG)
{
SanityManager.ASSERT(sd != null, "SchemaDescriptor is null");
}
}
// OBJECT METHODS
public String toString()
{
// Do not put this under SanityManager.DEBUG - it is needed for
// error reporting.
return "DROP VIEW " + fullTableName;
}
// INTERFACE METHODS
/**
* This is the guts of the Execution-time logic for DROP VIEW.
*
* @see ConstantAction#executeConstantAction
*
* @exception StandardException Thrown on failure
*/
public void executeConstantAction( Activation activation )
throws StandardException
{
TableDescriptor td;
ViewDescriptor vd;
LanguageConnectionContext lcc = activation.getLanguageConnectionContext();
DataDictionary dd = lcc.getDataDictionary();
/*
** Inform the data dictionary that we are about to write to it.
** There are several calls to data dictionary "get" methods here
** that might be done in "read" mode in the data dictionary, but
** it seemed safer to do this whole operation in "write" mode.
**
** We tell the data dictionary we're done writing at the end of
** the transaction.
*/
dd.startWriting(lcc);
/* Get the table descriptor. We're responsible for raising
* the error if it isn't found
*/
td = dd.getTableDescriptor(tableName, sd,
lcc.getTransactionExecute());
if (td == null)
{
throw StandardException.newException(SQLState.LANG_TABLE_NOT_FOUND_DURING_EXECUTION, fullTableName);
}
/* Verify that TableDescriptor represents a view */
if (td.getTableType() != TableDescriptor.VIEW_TYPE)
{
throw StandardException.newException(SQLState.LANG_DROP_VIEW_ON_NON_VIEW, fullTableName);
}
vd = dd.getViewDescriptor(td);
vd.drop(lcc, sd, td);
}
}