Java tutorial
/* * Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.sql; /** * * The representation (mapping) in the Java programming language of an SQL ROWID * value. An SQL ROWID is a built-in type, a value of which can be thought of as * an address for its identified row in a database table. Whether that address * is logical or, in any respects, physical is determined by its originating data * source. * <p> * Methods in the interfaces <code>ResultSet</code>, <code>CallableStatement</code>, * and <code>PreparedStatement</code>, such as <code>getRowId</code> and <code>setRowId</code> * allow a programmer to access a SQL <code>ROWID</code> value. The <code>RowId</code> * interface provides a method * for representing the value of the <code>ROWID</code> as a byte array or as a * <code>String</code>. * <p> * The method <code>getRowIdLifetime</code> in the interface <code>DatabaseMetaData</code>, * can be used * to determine if a <code>RowId</code> object remains valid for the duration of the transaction in * which the <code>RowId</code> was created, the duration of the session in which * the <code>RowId</code> was created, * or, effectively, for as long as its identified row is not deleted. In addition * to specifying the duration of its valid lifetime outside its originating data * source, <code>getRowIdLifetime</code> specifies the duration of a <code>ROWID</code> * value's valid lifetime * within its originating data source. In this, it differs from a large object, * because there is no limit on the valid lifetime of a large object within its * originating data source. * <p> * All methods on the <code>RowId</code> interface must be fully implemented if the * JDBC driver supports the data type. * * @see java.sql.DatabaseMetaData * @since 1.6 */ public interface RowId { /** * Compares this <code>RowId</code> to the specified object. The result is * <code>true</code> if and only if the argument is not null and is a RowId * object that represents the same ROWID as this object. * <p> * It is important * to consider both the origin and the valid lifetime of a <code>RowId</code> * when comparing it to another <code>RowId</code>. If both are valid, and * both are from the same table on the same data source, then if they are equal * they identify * the same row; if one or more is no longer guaranteed to be valid, or if * they originate from different data sources, or different tables on the * same data source, they may be equal but still * not identify the same row. * * @param obj the <code>Object</code> to compare this <code>RowId</code> object * against. * @return true if the <code>RowId</code>s are equal; false otherwise * @since 1.6 */ boolean equals(Object obj); /** * Returns an array of bytes representing the value of the SQL <code>ROWID</code> * designated by this <code>java.sql.RowId</code> object. * * @return an array of bytes, whose length is determined by the driver supplying * the connection, representing the value of the ROWID designated by this * java.sql.RowId object. */ byte[] getBytes(); /** * Returns a String representing the value of the SQL ROWID designated by this * <code>java.sql.RowId</code> object. * <p> *Like <code>java.sql.Date.toString()</code> * returns the contents of its DATE as the <code>String</code> "2004-03-17" * rather than as DATE literal in SQL (which would have been the <code>String</code> * DATE "2004-03-17"), toString() * returns the contents of its ROWID in a form specific to the driver supplying * the connection, and possibly not as a <code>ROWID</code> literal. * * @return a String whose format is determined by the driver supplying the * connection, representing the value of the <code>ROWID</code> designated * by this <code>java.sql.RowId</code> object. */ String toString(); /** * Returns a hash code value of this <code>RowId</code> object. * * @return a hash code for the <code>RowId</code> */ int hashCode(); }