index_element.h

Go to the documentation of this file.

/* Copyright (c) 2014, 2024, Oracle and/or its affiliates.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.
 
   This program is designed to work with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have either included with
   the program or referenced in the documentation.
 
   This program 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 2.0, for more details.
 
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
#ifndef DD__INDEX_ELEMENT_INCLUDED
#define DD__INDEX_ELEMENT_INCLUDED
 
#include "m_string.h"
#include "my_inttypes.h"
#include "sql/dd/sdi_fwd.h"            // dd::Sdi_wcontext
#include "sql/dd/types/weak_object.h"  // dd::Weak_object
 
namespace dd {
 
///////////////////////////////////////////////////////////////////////////
 
class Column;
class Index;
class Index_element_impl;
 
namespace tables {
class Index_column_usage;
}
 
///////////////////////////////////////////////////////////////////////////
 
class Index_element : virtual public Weak_object {
 public:
  typedef Index_element_impl Impl;
  typedef tables::Index_column_usage DD_table;
 
 public:
  enum enum_index_element_order { ORDER_UNDEF = 1, ORDER_ASC, ORDER_DESC };
 
 public:
  ~Index_element() override = default;
 
  /////////////////////////////////////////////////////////////////////////
  // index.
  /////////////////////////////////////////////////////////////////////////
 
  virtual const Index &index() const = 0;
 
  virtual Index &index() = 0;
 
  /////////////////////////////////////////////////////////////////////////
  // column.
  /////////////////////////////////////////////////////////////////////////
 
  virtual const Column &column() const = 0;
 
  virtual Column &column() = 0;
 
  /////////////////////////////////////////////////////////////////////////
  // ordinal_position.
  /////////////////////////////////////////////////////////////////////////
 
  virtual uint ordinal_position() const = 0;
 
  /////////////////////////////////////////////////////////////////////////
  // length.
  /////////////////////////////////////////////////////////////////////////
 
  virtual uint length() const = 0;
  virtual void set_length(uint length) = 0;
  virtual void set_length_null(bool is_null) = 0;
  virtual bool is_length_null() const = 0;
 
  /////////////////////////////////////////////////////////////////////////
  // order.
  /////////////////////////////////////////////////////////////////////////
 
  virtual enum_index_element_order order() const = 0;
  virtual void set_order(enum_index_element_order order) = 0;
 
  /////////////////////////////////////////////////////////////////////////
  // hidden.
  /////////////////////////////////////////////////////////////////////////
 
  virtual bool is_hidden() const = 0;
  virtual void set_hidden(bool hidden) = 0;
 
  /**
    Converts *this into json.
 
    Converts all member variables that are to be included in the sdi
    into json by transforming them appropriately and passing them to
    the rapidjson writer provided.
 
    @param wctx opaque context for data needed by serialization
    @param w rapidjson writer which will perform conversion to json
 
  */
 
  virtual void serialize(Sdi_wcontext *wctx, Sdi_writer *w) const = 0;
 
  /**
    Re-establishes the state of *this by reading sdi information from
    the rapidjson DOM subobject provided.
 
    Cross-references encountered within this object are tracked in
    sdictx, so that they can be updated when the entire object graph
    has been established.
 
    @param rctx stores book-keeping information for the
    deserialization process
    @param val subobject of rapidjson DOM containing json
    representation of this object
  */
 
  virtual bool deserialize(Sdi_rcontext *rctx, const RJ_Value &val) = 0;
 
  /**
    Check if index element (a.k.a. key part) is a prefix of the column used.
  */
  virtual bool is_prefix() const = 0;
};
 
///////////////////////////////////////////////////////////////////////////
 
}  // namespace dd
 
#endif  // DD__INDEX_ELEMENT_INCLUDED