/* * Copyright (c) 1996, 2005, 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; /** * An object that can be used to get information about the types * and properties of the columns in a <code>ResultSet</code> object. * The following code fragment creates the <code>ResultSet</code> object rs, * creates the <code>ResultSetMetaData</code> object rsmd, and uses rsmd * to find out how many columns rs has and whether the first column in rs * can be used in a <code>WHERE</code> clause. * <PRE> * *     ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2"); *     ResultSetMetaData rsmd = rs.getMetaData(); *     int numberOfColumns = rsmd.getColumnCount(); *     boolean b = rsmd.isSearchable(1); * * </PRE> */ public interface ResultSetMetaData extends Wrapper {     /**     * Returns the number of columns in this <code>ResultSet</code> object.     *     * @return the number of columns     * @exception SQLException if a database access error occurs     */    int getColumnCount() throws SQLException;     /**     * Indicates whether the designated column is automatically numbered.     *     * @param column the first column is 1, the second is 2, ...     * @return <code>true</code> if so; <code>false</code> otherwise     * @exception SQLException if a database access error occurs     */    boolean isAutoIncrement(int column) throws SQLException;     /**     * Indicates whether a column's case matters.     *     * @param column the first column is 1, the second is 2, ...     * @return <code>true</code> if so; <code>false</code> otherwise     * @exception SQLException if a database access error occurs     */    boolean isCaseSensitive(int column) throws SQLException;     /**     * Indicates whether the designated column can be used in a where clause.     *     * @param column the first column is 1, the second is 2, ...     * @return <code>true</code> if so; <code>false</code> otherwise     * @exception SQLException if a database access error occurs     */    boolean isSearchable(int column) throws SQLException;     /**     * Indicates whether the designated column is a cash value.     *     * @param column the first column is 1, the second is 2, ...     * @return <code>true</code> if so; <code>false</code> otherwise     * @exception SQLException if a database access error occurs     */    boolean isCurrency(int column) throws SQLException;     /**     * Indicates the nullability of values in the designated column.     *     * @param column the first column is 1, the second is 2, ...     * @return the nullability status of the given column; one of <code>columnNoNulls</code>,     *          <code>columnNullable</code> or <code>columnNullableUnknown</code>     * @exception SQLException if a database access error occurs     */    int isNullable(int column) throws SQLException;     /**     * The constant indicating that a     * column does not allow <code>NULL</code> values.     */    int columnNoNulls = 0;     /**     * The constant indicating that a     * column allows <code>NULL</code> values.     */    int columnNullable = 1;     /**     * The constant indicating that the     * nullability of a column's values is unknown.     */    int columnNullableUnknown = 2;     /**     * Indicates whether values in the designated column are signed numbers.     *     * @param column the first column is 1, the second is 2, ...     * @return <code>true</code> if so; <code>false</code> otherwise     * @exception SQLException if a database access error occurs     */    boolean isSigned(int column) throws SQLException;     /**     * Indicates the designated column's normal maximum width in characters.     *     * @param column the first column is 1, the second is 2, ...     * @return the normal maximum number of characters allowed as the width     *          of the designated column     * @exception SQLException if a database access error occurs     */    int getColumnDisplaySize(int column) throws SQLException;     /**     * Gets the designated column's suggested title for use in printouts and     * displays. The suggested title is usually specified by the SQL <code>AS</code>     * clause.  If a SQL <code>AS</code> is not specified, the value returned from     * <code>getColumnLabel</code> will be the same as the value returned by the     * <code>getColumnName</code> method.     *     * @param column the first column is 1, the second is 2, ...     * @return the suggested column title     * @exception SQLException if a database access error occurs     */    String getColumnLabel(int column) throws SQLException;     /**     * Get the designated column's name.     *     * @param column the first column is 1, the second is 2, ...     * @return column name     * @exception SQLException if a database access error occurs     */    String getColumnName(int column) throws SQLException;     /**     * Get the designated column's table's schema.     *     * @param column the first column is 1, the second is 2, ...     * @return schema name or "" if not applicable     * @exception SQLException if a database access error occurs     */    String getSchemaName(int column) throws SQLException;     /**     * Get the designated column's specified column size.     * For numeric data, this is the maximum precision.  For character data, this is the length in characters.     * For datetime datatypes, this is the length in characters of the String representation (assuming the     * maximum allowed precision of the fractional seconds component). For binary data, this is the length in bytes.  For the ROWID datatype,     * this is the length in bytes. 0 is returned for data types where the     * column size is not applicable.     *     * @param column the first column is 1, the second is 2, ...     * @return precision     * @exception SQLException if a database access error occurs     */    int getPrecision(int column) throws SQLException;     /**     * Gets the designated column's number of digits to right of the decimal point.     * 0 is returned for data types where the scale is not applicable.     *     * @param column the first column is 1, the second is 2, ...     * @return scale     * @exception SQLException if a database access error occurs     */    int getScale(int column) throws SQLException;     /**     * Gets the designated column's table name.     *     * @param column the first column is 1, the second is 2, ...     * @return table name or "" if not applicable     * @exception SQLException if a database access error occurs     */    String getTableName(int column) throws SQLException;     /**     * Gets the designated column's table's catalog name.     *     * @param column the first column is 1, the second is 2, ...     * @return the name of the catalog for the table in which the given column     *          appears or "" if not applicable     * @exception SQLException if a database access error occurs     */    String getCatalogName(int column) throws SQLException;     /**     * Retrieves the designated column's SQL type.     *     * @param column the first column is 1, the second is 2, ...     * @return SQL type from java.sql.Types     * @exception SQLException if a database access error occurs     * @see Types     */    int getColumnType(int column) throws SQLException;     /**     * Retrieves the designated column's database-specific type name.     *     * @param column the first column is 1, the second is 2, ...     * @return type name used by the database. If the column type is     * a user-defined type, then a fully-qualified type name is returned.     * @exception SQLException if a database access error occurs     */    String getColumnTypeName(int column) throws SQLException;     /**     * Indicates whether the designated column is definitely not writable.     *     * @param column the first column is 1, the second is 2, ...     * @return <code>true</code> if so; <code>false</code> otherwise     * @exception SQLException if a database access error occurs     */    boolean isReadOnly(int column) throws SQLException;     /**     * Indicates whether it is possible for a write on the designated column to succeed.     *     * @param column the first column is 1, the second is 2, ...     * @return <code>true</code> if so; <code>false</code> otherwise     * @exception SQLException if a database access error occurs     */    boolean isWritable(int column) throws SQLException;     /**     * Indicates whether a write on the designated column will definitely succeed.     *     * @param column the first column is 1, the second is 2, ...     * @return <code>true</code> if so; <code>false</code> otherwise     * @exception SQLException if a database access error occurs     */    boolean isDefinitelyWritable(int column) throws SQLException;     //--------------------------JDBC 2.0-----------------------------------     /**     * <p>Returns the fully-qualified name of the Java class whose instances     * are manufactured if the method <code>ResultSet.getObject</code>     * is called to retrieve a value     * from the column.  <code>ResultSet.getObject</code> may return a subclass of the     * class returned by this method.     *     * @param column the first column is 1, the second is 2, ...     * @return the fully-qualified name of the class in the Java programming     *         language that would be used by the method     * <code>ResultSet.getObject</code> to retrieve the value in the specified     * column. This is the class name used for custom mapping.     * @exception SQLException if a database access error occurs     * @since 1.2     */    String getColumnClassName(int column) throws SQLException;}