MultiRowOperations.h

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/*
 * Copyright 2009 Savarese Software Research Corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.savarese.com/software/ApacheLicense-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef __SSRC_WSPR_DATABASE_MULTI_ROW_OPERATIONS_H
#define __SSRC_WSPR_DATABASE_MULTI_ROW_OPERATIONS_H

#include <ssrc/wispers/database/RowOperations.h>

__BEGIN_NS_SSRC_WSPR_DATABASE

template<typename Row, typename ValueBinder = DefaultValueBinder,
         typename ValueLoader = DefaultValueLoader,
         typename RowOps = RowOperations<Row,ValueBinder,ValueLoader> >
struct MultiRowOperations : public RowOps {
  typedef RowOps super;

  WISP_IMPORT_T(super, row_type);
  WISP_IMPORT_T(super, find_result_type);
  WISP_IMPORT_T(super, binder_type);
  WISP_IMPORT_T(super, loader_type);

private:
  Database & _db;
  const string _table_name;
  string _select_columns;
  
public:
  MultiRowOperations(Database & db,
                     const binder_type & binder = DefaultValueBinder(),
                     const loader_type & loader = DefaultValueLoader(),
                     const bool explicit_columns = super::ImplicitColumns,
                     const string & table_name = row_type::table_name()) :
    super(db, binder, loader, explicit_columns, table_name),
    _db(db), _table_name(table_name),
    _select_columns(super::select_columns_expression(explicit_columns))
  { }

  prepared_statement_ptr prepare_find_rows(const unsigned int n)
    SSRC_DECL_THROW(DatabaseException)
  {
    using detail::PrimaryKeyCond;
    std::ostringstream query;

    query << "SELECT " << _select_columns << " FROM `"
          << _table_name << "` WHERE ";

    for(unsigned int i = 0; i < n - 1; ++i) {
      PrimaryKeyCond<row_type, row_type::PrimaryKeyCount - 1>::apply((query << "(")) << ") OR ";
    }

    PrimaryKeyCond<row_type, row_type::PrimaryKeyCount - 1>::apply((query << "(")) << ")";

    return _db.prepare(query.str());
  }

  template<typename Iterator, typename functor>
  unsigned int for_each_row(const Iterator & begin, const Iterator & end,
                            const unsigned int size,
                            const functor &  apply)
    SSRC_DECL_THROW(DatabaseException)
  {
    prepared_statement_ptr && query = prepare_find_rows(size);
    typename binder_type::binder_type & binder_ = super::binder.binder(*query);
    unsigned int i = 0;

    for(Iterator it = begin; it != end; ++it, i+=row_type::PrimaryKeyCount) {
      row_type::bind_primary_key(binder_, *it, i);
    }

    return query->for_each(apply);
  }
};

template<typename Row, typename ValueBinder = DefaultValueBinder,
         typename ValueLoader = DefaultValueLoader>
struct MultiRowOperationsReadOnly :
  public MultiRowOperations<Row, ValueBinder, ValueLoader,
                            RowOperationsReadOnly<Row,ValueBinder,ValueLoader> >
{
  typedef
  MultiRowOperations<Row, ValueBinder, ValueLoader,
                     RowOperationsReadOnly<Row,ValueBinder,ValueLoader> >
  super;

  WISP_IMPORT_T(super, row_type);
  WISP_IMPORT_T(super, find_result_type);
  WISP_IMPORT_T(super, binder_type);
  WISP_IMPORT_T(super, loader_type);

  MultiRowOperationsReadOnly(Database & db,
                             const binder_type & binder = DefaultValueBinder(),
                             const loader_type & loader = DefaultValueLoader(),
                             const bool explicit_columns =
                             super::ImplicitColumns,
                             const string & table_name =
                             row_type::table_name()) :
    super(db, binder, loader, explicit_columns, table_name)
  { }
};

__END_NS_SSRC_WSPR_DATABASE

#endif