jdbcresultset.java

纯Java的数据库

     *
     * @param columnName the SQL name of the column
     * @return the column value; if the value is SQL <code>NULL</code>, the
     * value returned is <code>null</code>
     * @exception SQLException if a database access error occurs
     */
    public Timestamp getTimestamp(String columnName) throws SQLException {
        return getTimestamp(findColumn(columnName));
    }

    /**
     * <!-- start generic documentation -->
     * Retrieves the value of the designated column in the current row
     * of this <code>ResultSet</code> object as a stream of
     * ASCII characters. The value can then be read in chunks from the
     * stream. This method is particularly
     * suitable for retrieving large <code>LONGVARCHAR</code> values.
     * The JDBC driver will
     * do any necessary conversion from the database format into ASCII.
     *
     * <P><B>Note:</B> All the data in the returned stream must be
     * read prior to getting the value of any other column. The next
     * call to a getter method implicitly closes the stream. Also, a
     * stream may return <code>0</code> when the method <code>available</code>
     * is called whether there is data available or not. <p>
     * <!-- end generic documentation -->
     *
     * @param columnName the SQL name of the column
     * @return a Java input stream that delivers the database column value
     * as a stream of one-byte ASCII characters.
     * If the value is SQL <code>NULL</code>,
     * the value returned is <code>null</code>.
     * @exception SQLException if a database access error occurs
     * @see #getAsciiStream(int)
     */
    public java.io.InputStream getAsciiStream(String columnName)
    throws SQLException {
        return getAsciiStream(findColumn(columnName));
    }

    /**
     * <!-- start generic documentation -->
     * Retrieves the value of the designated column in the current row
     * of this <code>ResultSet</code> object as a stream of two-byte
     * Unicode characters. The first byte is the high byte; the second
     * byte is the low byte.
     *
     * The value can then be read in chunks from the
     * stream. This method is particularly
     * suitable for retrieving large <code>LONGVARCHAR</code> values.
     * The JDBC technology-enabled driver will
     * do any necessary conversion from the database format into Unicode.
     *
     * <P><B>Note:</B> All the data in the returned stream must be
     * read prior to getting the value of any other column. The next
     * call to a getter method implicitly closes the stream.
     * Also, a stream may return <code>0</code> when the method
     * <code>InputStream.available</code> is called, whether there
     * is data available or not. <p>
     * <!-- end generic documentation -->
     *
     * @param columnName the SQL name of the column
     * @return a Java input stream that delivers the database column value
     *    as a stream of two-byte Unicode characters.
     *    If the value is SQL <code>NULL</code>, the value returned
     *    is <code>null</code>.
     * @exception SQLException if a database access error occurs
     * @deprecated use <code>getCharacterStream</code> instead
     * @see #getUnicodeStream(int)
     */

//#ifdef DEPRECATEDJDBC
    public java.io.InputStream getUnicodeStream(String columnName)
    throws SQLException {
        return getUnicodeStream(findColumn(columnName));
    }

//#endif

    /**
     * <!-- start generic documentation -->
     * Retrieves the value of the designated column in the current row
     * of this <code>ResultSet</code> object as a stream of uninterpreted
     * <code>byte</code>s.
     * The value can then be read in chunks from the
     * stream. This method is particularly
     * suitable for retrieving large <code>LONGVARBINARY</code>
     * values.
     *
     * <P><B>Note:</B> All the data in the returned stream must be
     * read prior to getting the value of any other column. The next
     * call to a getter method implicitly closes the stream. Also, a
     * stream may return <code>0</code> when the method <code>available</code>
     * is called whether there is data available or not. <p>
     * <!-- end generic documentation -->
     *
     * @param columnName the SQL name of the column
     * @return a Java input stream that delivers the database column value
     * as a stream of uninterpreted bytes;
     * if the value is SQL <code>NULL</code>, the result is <code>null</code>
     * @exception SQLException if a database access error occurs
     */
    public java.io.InputStream getBinaryStream(String columnName)
    throws SQLException {
        return getBinaryStream(findColumn(columnName));
    }

    //=====================================================================
    // Advanced features:
    //=====================================================================

    /**
     * <!-- start generic documentation -->
     * Retrieves the first warning reported by calls on this
     * <code>ResultSet</code> object.
     * Subsequent warnings on this <code>ResultSet</code> object
     * will be chained to the <code>SQLWarning</code> object that
     * this method returns.
     *
     * <P>The warning chain is automatically cleared each time a new
     * row is read.  This method may not be called on a <code>ResultSet</code>
     * object that has been closed; doing so will cause an
     * <code>SQLException</code> to be thrown.
     * <P>
     * <B>Note:</B> This warning chain only covers warnings caused
     * by <code>ResultSet</code> methods.  Any warning caused by
     * <code>Statement</code> methods
     * (such as reading OUT parameters) will be chained on the
     * <code>Statement</code> object. <p>
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Up to and including 1.7.1, HSQLDB does not produce
     * <code>SQLWarning</code> objects. This method always returns
     * <code>null</code>.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @return the first <code>SQLWarning</code> object reported or
     *    <code>null</code> if there are none <p>
     *
     * Up to and including 1.7.1, HSQLDB always returns null. <p>
     * @exception SQLException if a database access error occurs or this
     *    method is called on a closed result set
     */
    public SQLWarning getWarnings() throws SQLException {
        return null;
    }

    /**
     * <!-- start generic documentation -->
     * Clears all warnings reported on this <code>ResultSet</code> object.
     * After this method is called, the method <code>getWarnings</code>
     * returns <code>null</code> until a new warning is
     * reported for this <code>ResultSet</code> object. <p>
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Including 1.7.1, HSQLDB does not produce <code>SQLWarning</code>
     * objects on any ResultSet object warning chain; calls to this method
     * are ignored.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @exception SQLException if a database access error occurs
     */
    public void clearWarnings() throws SQLException {}

    /**
     * <!-- start generic documentation -->
     * Retrieves the name of the SQL cursor used by this
     * <code>ResultSet</code> object.
     *
     * <P>In SQL, a result table is retrieved through a cursor that is
     * named. The current row of a result set can be updated or deleted
     * using a positioned update/delete statement that references the
     * cursor name. To insure that the cursor has the proper isolation
     * level to support update, the cursor's <code>SELECT</code> statement
     * should be of the form <code>SELECT FOR UPDATE</code>. If
     * <code>FOR UPDATE</code> is omitted, the positioned updates may fail.
     *
     * <P>The JDBC API supports this SQL feature by providing the name of the
     * SQL cursor used by a <code>ResultSet</code> object.
     * The current row of a <code>ResultSet</code> object
     * is also the current row of this SQL cursor.
     *
     * <P><B>Note:</B> If positioned update is not supported, a
     * <code>SQLException</code> is thrown. <p>
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Including 1.7.2, HSQLDB does not support this feature.  <p>
     *
     * Calling this method always throws an <code>SQLException</code>,
     * stating that the operation is not supported.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @return the SQL name for this <code>ResultSet</code> object's cursor
     * @exception SQLException if a database access error occurs
     */
    public String getCursorName() throws SQLException {
        throw Util.notSupported();
    }

    /**
     * <!-- start generic documentation -->
     * Retrieves the  number, types and properties of
     * this <code>ResultSet</code> object's columns. <p>
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * <B>Example:</B> <p>
     *
     * The following code fragment creates a <code>ResultSet</code> object rs,
     * creates a <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. <p>
     *
     * <pre class="JavaCodeExample">
     * ResultSet         rs              = stmt.<b>executeQuery</b>(<span class="JavaStringLiteral">"SELECT a, b, c FROM TABLE2"</span>);
     * ResultSetMetaData rsmd = rs.<b>getMetaData</b>();<br>
     * int numberOfColumns = rsmd.<b>getColumnCount</b>();<br>
     * boolean b = rsmd.<b>isSearchable</b>(1);<br>
     * </pre>
     *
     * <hr>
     *
     * <B>Warning:</B> <p>
     *
     * Including 1.7.1, HSQLDB did not generate accurate
     * <code>ResultSetMetaData</code>.  Below were the the most important
     * methods to consider: <p>
     *
     * <ol>
     * <li>isAutoIncrement(int) <i>always</i> returned <code>false</code></li>
     * <li>isCurrency(int) <i>always</i> returned <code>false</code></li>
     * <li>isNullable(int) <i>always</i> returned
     *     <code>columnNullableUnknown</code></li>
     * <li>getColumnDisplaySize(int) returned zero for all valid column
     *     numbers</li>
     * <li>getSchemaName(int) <i>always</i> returned
     *  <span class="JavaStringLiteral">""</span></li>
     * <li>getPrecision(int) <i>always</i> returned zero</li>
     * <li>getScale(int) <i>always</i> returned zero</li>
     * <li>getCatalogName(int) <i>always</i> returned
     *  <span class="JavaStringLiteral">""</span></li>
     * </ol> <p>
     *
     * <hr>
     *
     * Starting with 1.7.2, ResultSetMetaData has been split out into its own
     * interface implemenation (jdbcResultSetMetaData), support has been
     * improved considerably for a number of methods and behaviour has
     * been altered slightly in many areas.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @return the description of this <code>ResultSet</code> object's columns
     * @exception SQLException if a database access error occurs
     * @see jdbcResultSetMetaData
     */
    public ResultSetMetaData getMetaData() throws SQLException {

        if (rsmd == null) {
            rsmd = new jdbcResultSetMetaData(this, connProperties);
        }

        return rsmd;
    }

    /**
     * <!-- start generic documentation -->
     * Gets the value of the designated column in the current row
     * of this <code>ResultSet</code> object as
     * an <code>Object</code> in the Java programming language.
     *
     * <p>This method will return the value of the given column as a
     * Java object.  The type of the Java object will be the default
     * Java object type corresponding to the column's SQL type,
     * following the mapping for built-in types specified in the JDBC
     * specification. If the value is an SQL <code>NULL</code>,
     * the driver returns a Java <code>null</code>.
     *
     * <p>This method may also be used to read datatabase-specific
     * abstract data types.
     *
     * In the JDBC 2.0 API, the behavior of method
     * <code>getObject</code> is extended to materialize
     * data of SQL user-defined types.  When a column contains
     * a structured or distinct value, the behavior of this method is as
     * if it were a call to: <code>getObject(columnIndex,
     * this.getStatement().getConnection().getTypeMap())</code>. <p>
     * <!-- end generic documentation -->
     *
     * @param columnIndex the first column is 1, the second is 2, ...
     * @return a <code>java.lang.Object</code> holding the column value
     * @exception SQLException if a database access error occurs
     */
    public Object getObject(int co