/*

 * Copyright 1996-2005 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.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;

}