dbmm.java

另外一种持久性o/m软件

package org.apache.torque.adapter;

/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * 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.
 */

import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Date;
import java.text.SimpleDateFormat;

/**
 * This is used in order to connect to a MySQL database using the MM
 * drivers.  Simply comment the above and uncomment this code below and
 * fill in the appropriate values for DB_NAME, DB_HOST, DB_USER,
 * DB_PASS.
 *
 * <P><A HREF="http://www.worldserver.com/mm.mysql/">
 * http://www.worldserver.com/mm.mysql/</A>
 * <p>"jdbc:mysql://" + DB_HOST + "/" + DB_NAME + "?user=" +
 * DB_USER + "&password=" + DB_PASS;
 *
 * @author <a href="mailto:[e-mail]">Jon S. Stevens</a>
 * @author <a href="mailto:[e-mail]">Brett McLaughlin</a>
 * @author <a href="mailto:[e-mail]">Daniel Rall</a>
 * @version $Id: DBMM.java,v 1.13 2005/01/31 19:43:55 tfischer Exp $
 */
public class DBMM extends DB
{
    
    /** A specialized date format for MySQL. */
    private static final String DATE_FORMAT = "yyyyMMddHHmmss";

    /**
     * Empty protected constructor.
     */
    protected DBMM()
    {
    }

    /**
     * This method is used to ignore case.
     *
     * @param in The string to transform to upper case.
     * @return The upper case string.
     */
    public String toUpperCase(String in)
    {
        return in;
    }

    /**
     * This method is used to ignore case.
     *
     * @param in The string whose case to ignore.
     * @return The string in a case that can be ignored.
     */
    public String ignoreCase(String in)
    {
        return in;
    }

    /**
     * @see org.apache.torque.adapter.DB#getIDMethodType()
     */
    public String getIDMethodType()
    {
        return AUTO_INCREMENT;
    }

    /**
     * Returns the SQL to get the database key of the last row
     * inserted, which in this case is <code>SELECT
     * LAST_INSERT_ID()</code>.
     *
     * @see org.apache.torque.adapter.DB#getIDMethodSQL(Object obj)
     */
    public String getIDMethodSQL(Object obj)
    {
        return "SELECT LAST_INSERT_ID()";
    }

    /**
     * Locks the specified table.
     *
     * @param con The JDBC connection to use.
     * @param table The name of the table to lock.
     * @exception SQLException No Statement could be created or
     * executed.
     */
    public void lockTable(Connection con, String table) throws SQLException
    {
        Statement statement = con.createStatement();
        StringBuffer stmt = new StringBuffer();
        stmt.append("LOCK TABLE ").append(table).append(" WRITE");
        statement.executeUpdate(stmt.toString());
    }

    /**
     * Unlocks the specified table.
     *
     * @param con The JDBC connection to use.
     * @param table The name of the table to unlock.
     * @exception SQLException No Statement could be created or
     * executed.
     */
    public void unlockTable(Connection con, String table) throws SQLException
    {
        Statement statement = con.createStatement();
        statement.executeUpdate("UNLOCK TABLES");
    }

    /**
     * This method is used to chek whether the database natively
     * supports limiting the size of the resultset.
     *
     * @return True.
     */
    public boolean supportsNativeLimit()
    {
        return true;
    }

    /**
     * This method is used to chek whether the database natively
     * supports returning results starting at an offset position other
     * than 0.
     *
     * @return True.
     */
    public boolean supportsNativeOffset()
    {
        return true;
    }

    /**
     * This method is used to chek whether the database supports
     * limiting the size of the resultset.
     *
     * @return LIMIT_STYLE_MYSQL.
     */
    public int getLimitStyle()
    {
        return DB.LIMIT_STYLE_MYSQL;
    }

    /**
     * This method overrides the JDBC escapes used to format dates
     * using a <code>DateFormat</code>.  As of version 2.0.11, the MM
     * JDBC driver does not implement JDBC 3.0 escapes.
     *
     * @param date the date to format
     * @return The properly formatted date String.
     */
    public String getDateString(Date date)
    {
        char delim = getStringDelimiter();
        return (delim + new SimpleDateFormat(DATE_FORMAT).format(date) + delim);
    }
}