createschemaconstantaction.java

derby database source code.good for you.

/*

   Derby - Class org.apache.derby.impl.sql.execute.CreateSchemaConstantAction

   Copyright 1998, 2004 The Apache Software Foundation or its licensors, as applicable.

   Licensed 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.sql.execute.ConstantAction;

import org.apache.derby.iapi.store.access.TransactionController;

import org.apache.derby.iapi.sql.dictionary.DataDescriptorGenerator;
import org.apache.derby.iapi.sql.dictionary.DataDictionary;
import org.apache.derby.iapi.sql.dictionary.SchemaDescriptor;
import org.apache.derby.iapi.sql.conn.LanguageConnectionContext;

import org.apache.derby.iapi.reference.SQLState;

import org.apache.derby.iapi.sql.Activation;

import org.apache.derby.iapi.error.StandardException;

import org.apache.derby.iapi.services.sanity.SanityManager;

import org.apache.derby.catalog.UUID;

/**
 *	This class describes actions that are ALWAYS performed for a
 *	CREATE SCHEMA Statement at Execution time.
 *
 *	@author jamie 
 */

class CreateSchemaConstantAction extends DDLConstantAction
{

	private final String					aid;	// authorization id
	private final String					schemaName;
	

	// CONSTRUCTORS

	/**
	 * Make the ConstantAction for a CREATE SCHEMA statement.
	 * When executed, will set the default schema to the
	 * new schema if the setToDefault parameter is set to
	 * true.
	 *
	 *  @param schemaName	Name of table.
	 *  @param aid			Authorizaton id
	 *  @param schemaId		ID of table. If null, we allocate one.
	 *	@param setToDefault	if true, set the default schema to
	 *			the new schema once it is created.
	 */
	CreateSchemaConstantAction(
								String			schemaName,
								String			aid)
	{
		this.schemaName = schemaName;
		this.aid = aid;
	}

	///////////////////////////////////////////////
	//
	// OBJECT SHADOWS
	//
	///////////////////////////////////////////////

	public	String	toString()
	{
		// Do not put this under SanityManager.DEBUG - it is needed for
		// error reporting.
		return "CREATE SCHEMA " + schemaName;
	}

	// INTERFACE METHODS


	/**
	 *	This is the guts of the Execution-time logic for CREATE SCHEMA.
	 *
	 *	@see ConstantAction#executeConstantAction
	 *
	 * @exception StandardException		Thrown on failure
	 */
	public void	executeConstantAction( Activation activation )
						throws StandardException
	{
		LanguageConnectionContext lcc = activation.getLanguageConnectionContext();
		DataDictionary dd = lcc.getDataDictionary();
		TransactionController tc = lcc.getTransactionExecute();
		DataDescriptorGenerator ddg = dd.getDataDescriptorGenerator();

		SchemaDescriptor sd = dd.getSchemaDescriptor(schemaName, lcc.getTransactionExecute(), false);

		//if the schema descriptor is an in-memory schema, we donot throw schema already exists exception for it.
		//This is to handle in-memory SESSION schema for temp tables
		if ((sd != null) && (sd.getUUID() != null))
		{
			throw StandardException.newException(SQLState.LANG_OBJECT_ALREADY_EXISTS, "Schema" , schemaName);
		}

		UUID tmpSchemaId = dd.getUUIDFactory().createUUID();

		/*
		** AID defaults to connection authorization if not 
		** specified in CREATE SCHEMA (if we had module
	 	** authorizations, that would be the first check
		** for default, then session aid).
		*/
		String thisAid = aid;
		if (thisAid == null)
		{
			thisAid = lcc.getAuthorizationId();
		}

		/*
		** 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);

		sd = ddg.newSchemaDescriptor(schemaName,
									thisAid,
									tmpSchemaId);

		dd.addDescriptor(sd, null, DataDictionary.SYSSCHEMAS_CATALOG_NUM, false, tc);
	}
}