/* Statement.java -- Interface for executing SQL statements.
   Copyright (C) 1999, 2000, 2002, 2006 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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any later version.
 
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General Public License for more details.

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02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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terms of your choice, provided that you also meet, for each linked
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this exception to your version of the library, but you are not
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package java.sql;

/**
 * This interface provides a mechanism for executing SQL statements.
 *
 * @author Aaron M. Renn (arenn@urbanophile.com)
 */
public interface Statement 
{
  int CLOSE_CURRENT_RESULT = 1;
  int KEEP_CURRENT_RESULT = 2;
  int CLOSE_ALL_RESULTS = 3;
  int SUCCESS_NO_INFO = -2;
  int EXECUTE_FAILED = -3;
  int RETURN_GENERATED_KEYS = 1;
  int NO_GENERATED_KEYS = 2;

  /**
   * This method executes the specified SQL SELECT statement and returns a
   * (possibly empty) <code>ResultSet</code> with the results of the query.
   *
   * @param sql The SQL statement to execute.
   * @return The result set of the SQL statement.
   * @exception SQLException If an error occurs.
   */
  ResultSet executeQuery(String sql) throws SQLException;

  /**
   * This method executes the specified SQL INSERT, UPDATE, or DELETE statement
   * and returns the number of rows affected, which may be 0.
   * 
   * @param sql The SQL statement to execute.
   * @return The number of rows affected by the SQL statement.
   * @exception SQLException If an error occurs.
   */
  int executeUpdate(String sql) throws SQLException;

  /**
   * This method closes the statement and frees any associated resources.
   *
   * @exception SQLException If an error occurs.
   */
  void close() throws SQLException;

  /**
   * This method returns the maximum length of any column value in bytes.
   *
   * @return The maximum length of any column value in bytes.
   * @exception SQLException If an error occurs.
   */
  int getMaxFieldSize() throws SQLException;

  /**
   * This method sets the limit for the maximum length of any column in bytes.
   *
   * @param maxSize The new maximum length of any column in bytes.
   * @exception SQLException If an error occurs.
   */
  void setMaxFieldSize(int maxSize) throws SQLException;

  /**
   * This method returns the maximum possible number of rows in a result set.
   *
   * @return The maximum possible number of rows in a result set.
   * @exception SQLException If an error occurs.
   */
  int getMaxRows() throws SQLException;

  /**
   * This method sets the maximum number of rows that can be present in a
   * result set.
   *
   * @param maxRows The maximum possible number of rows in a result set.
   * @exception SQLException If an error occurs.
   */
  void setMaxRows(int maxRows) throws SQLException;

  /**
   * This method sets the local escape processing mode on or off.  The
   * default value is on.
   *
   * @param escape <code>true</code> to enable local escape processing, 
   *               <code>false</code> to disable it.
   * @exception SQLException If an error occurs.
   */
  void setEscapeProcessing(boolean escape) throws SQLException;

  /**
   * The method returns the number of seconds a statement may be in process
   * before timing out.  A value of 0 means there is no timeout.
   *
   * @return The SQL statement timeout in seconds.
   * @exception SQLException If an error occurs.
   */
  int getQueryTimeout() throws SQLException;

  /**
   * This method sets the number of seconds a statement may be in process
   * before timing out.  A value of 0 means there is no timeout.
   *
   * @param seconds The new SQL statement timeout value.
   * @exception SQLException If an error occurs.
   */
  void setQueryTimeout(int seconds) throws SQLException;

  /**
   * This method cancels an outstanding statement, if the database supports
   * that operation.
   *
   * @exception SQLException If an error occurs.
   */
  void cancel() throws SQLException;

  /**
   * This method returns the first SQL warning attached to this statement.
   * Subsequent warnings will be chained to this one.
   *
   * @return The first SQL warning for this statement.
   * @exception SQLException If an error occurs.
   */
  SQLWarning getWarnings() throws SQLException;

  /**
   * This method clears any SQL warnings that have been attached to this
   * statement.
   *
   * @exception SQLException If an error occurs.
   */
  void clearWarnings() throws SQLException;

  /**
   * This method sets the cursor name that will be used by the result set.
   *
   * @param name The cursor name to use for this statement.
   * @exception SQLException If an error occurs.
   */
  void setCursorName(String name) throws SQLException;

  /**
   * This method executes an arbitrary SQL statement of any time.  The
   * methods <code>getResultSet</code>, <code>getMoreResults</code> and
   * <code>getUpdateCount</code> retrieve the results.
   *
   * @return <code>true</code> if a result set was returned, <code>false</code>
   *         if an update count was returned.
   * @exception SQLException If an error occurs.
   */
  boolean execute(String sql) throws SQLException;

  /**
   * This method returns the result set of the SQL statement that was
   * executed.  This should be called only once per result set returned.
   *
   * @return The result set of the query, or <code>null</code> if there was
   *         no result set (for example, if the statement was an UPDATE).
   * @exception SQLException If an error occurs.
   * @see #execute(String)
   * @see #execute(String, int)
   * @see #execute(String, int[])
   * @see #execute(String, String[])
   */
  ResultSet getResultSet() throws SQLException;

  /**
   * This method returns the update count of the SQL statement that was
   * executed.  This should be called only once per executed SQL statement.
   *
   * @return The update count of the query, or -1 if there was no update
   *         count (for example, if the statement was a SELECT).
   * @exception SQLException If an error occurs.
   * @see #execute(String)
   * @see #execute(String, int)
   * @see #execute(String, int[])
   * @see #execute(String, String[])
   */
  int getUpdateCount() throws SQLException;

  /**
   * This method advances the result set pointer to the next result set, 
   * which can then be retrieved using <code>getResultSet</code>
   *
   * @return <code>true</code> if there is another result set, 
   *         <code>false</code> otherwise (for example, the next result is an
   *         update count).
   * @exception SQLException If an error occurs.
   * @see #execute(String)
   * @see #execute(String, int)
   * @see #execute(String, int[])
   * @see #execute(String, String[])
   */
  boolean getMoreResults() throws SQLException;

  /**
   * This method informs the driver which direction the result set will
   * be accessed in.
   *
   * @param direction The direction the result set will be accessed in (?????)
   * @exception SQLException If an error occurs.
   */
  void setFetchDirection(int direction) throws SQLException;

  /**
   * This method returns the current direction that the driver thinks the
   * result set will be accessed int.
   *
   * @return The direction the result set will be accessed in (????)
   * @exception SQLException If an error occurs.
   */
  int getFetchDirection() throws SQLException;

  /**
   * This method informs the driver how many rows it should fetch from the
   * database at a time.
   *
   * @param numRows The number of rows the driver should fetch at a time
   *                to populate the result set.
   * @exception SQLException If an error occurs.
   */
  void setFetchSize(int numRows) throws SQLException;

  /**
   * This method returns the number of rows the driver believes should be
   * fetched from the database at a time.
   *
   * @return The number of rows that will be fetched from the database at a time.
   * @exception SQLException If an error occurs.
   */
  int getFetchSize() throws SQLException;

  /**
   * This method returns the concurrency type of the result set for this
   * statement. This will be one of the concurrency types defined in
   * <code>ResultSet</code>.
   *
   * @return The concurrency type of the result set for this statement.
   * @exception SQLException If an error occurs.
   * @see ResultSet
   */
  int getResultSetConcurrency() throws SQLException;

  /**
   * This method returns the result set type for this statement.  This will
   * be one of the result set types defined in <code>ResultSet</code>.
   *
   * @return The result set type for this statement.
   * @exception SQLException If an error occurs.
   * @see ResultSet
   */
  int getResultSetType() throws SQLException;

  /**
   * This method adds a SQL statement to a SQL batch.  A driver is not
   * required to implement this method.
   *
   * @param sql The sql statement to add to the batch.
   * @exception SQLException If an error occurs.
   */
  void addBatch(String sql) throws SQLException;

  /**
   * This method clears out any SQL statements that have been populated in
   * the current batch.  A driver is not required to implement this method.
   *
   * @exception SQLException If an error occurs.
   */
  void clearBatch() throws SQLException;

  /**
   * This method executes the SQL batch and returns an array of update
   * counts - one for each SQL statement in the batch - ordered in the same
   * order the statements were added to the batch.  A driver is not required
   * to implement this method.
   *
   * @return An array of update counts for this batch.
   * @exception SQLException If an error occurs.
   */
  int[] executeBatch() throws SQLException;

  /**
   * This method returns the <code>Connection</code> instance that was
   * used to create this object.
   *
   * @return The connection used to create this object.
   * @exception SQLException If an error occurs.
   */
  Connection getConnection() throws SQLException;

  /**
   * @since 1.4
   */
  boolean getMoreResults(int current) throws SQLException;

  /**
   * @since 1.4
   */
  ResultSet getGeneratedKeys() throws SQLException;

  /**
   * @since 1.4
   */
  int executeUpdate(String sql, int autoGeneratedKeys)
    throws SQLException;

  /**
   * @since 1.4
   */
  int executeUpdate(String sql, int[] columnIndexes)
    throws SQLException;

  /**
   * @since 1.4
   */
  int executeUpdate(String sql, String[] columnNames)
    throws SQLException;

  /**
   * @since 1.4
   */
  boolean execute(String sql, int autoGeneratedKeys)
    throws SQLException;

  /**
   * @since 1.4
   */
  boolean execute(String sql, int[] columnIndexes) throws SQLException;

  /**
   * @since 1.4
   */
  boolean execute(String sql, String[] columnNames)
    throws SQLException;

  /**
   * @since 1.4
   */
  int getResultSetHoldability() throws SQLException;
}