Boost组件multi_index_container组合查询实例(1)

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1. 引子

 

在 实例 (1) 、实例 ( 续 2) 、实例 ( 续 3) 、实例 ( 续 4) 、实例 ( 续 5) 这个系列的例子中，我们演示的是对多个索引的整体查询，即对元组 r=(x,y,z,a,b) ，其中 为索引， 为一个数据对，我们在对集合 R={r} 这个多索引的数据表查询时，直接给定索引 。

 

如果我们想查询 x 索引值为 x0 的所有数据，或者查询 x 、 y 索引值分别为 x0 、 y0 的所有数据，即这种组合查询，该如何查？上述系列的例子能否查得到？如果查不到，该如何调整 MyContainer_T 的结构？

 

有兴趣的读者可以自行实验，上述系列的例子不支持这种组合查询。

那么组合查询如何改写 MyContainer_T 的结构？这就是本系列要讲的 组合查询 。

 

关于组合查询的讲解，可以参考后续的文章。

 

2. 修改 MyContainer_T 的结构

struct x_key :composite_key <

  MyTest,

  BOOST_MULTI_INDEX_MEMBER (MyTest, int, x)

>{};

 

struct xy_key :composite_key <

  MyTest,

  BOOST_MULTI_INDEX_MEMBER (MyTest, int, x),

  BOOST_MULTI_INDEX_MEMBER (MyTest, int, y)

>{};

 

struct xyz_key :composite_key <

    MyTest,

    BOOST_MULTI_INDEX_MEMBER (MyTest, int, x),

    BOOST_MULTI_INDEX_MEMBER (MyTest, int, y),

    BOOST_MULTI_INDEX_MEMBER (MyTest, int, z)

>{};

 

struct MyIndex_X_Tag {};

struct MyIndex_XY_Tag {};

struct MyIndex_XYZ_Tag {};

 

typedef multi_index_container <

    MyTest*,

    indexed_by<

        ordered_non_unique MyIndex_X_Tag >, x_key ,   composite_key_result_less >,

        ordered_non_unique MyIndex_XY_Tag >, xy_key ,composite_key_result_less >,

        ordered_unique MyIndex_XYZ_Tag >, xyz_key ,   composite_key_result_less >

    >

>MyContainer_T ;

 

// 分别定义第 1 、 2 、 3 种组合查询对应的 contaniner 的类型

typedef nth_index<MyContainer_T , 0>::type MyContainer_X_T ;

typedef nth_index<MyContainer_T , 1>::type MyContainer_XY_T ;

typedef nth_index<MyContainer_T , 2>::type MyContainer_XYZ_T ;

3. 代码及运行结果

 

multiindexcontainer11.cpp

/** * boost multi index container test * platform: win32, visual studio 2005/2010; Linux, gcc4.1.2 */ #include #include #include #include #include using namespace std; using namespace boost::multi_index; using boost::multi_index_container; //define data to be indexed typedef struct { int a; int b; }MyData; //define object to be indexed class MyTest { public: int x; int y; int z; MyData myData; public: MyTest(int x_, int y_, int z_, int a, int b):x(x_), y(y_), z(z_) { myData.a = a; myData.b = b; } ~MyTest() { cout << "(" << x << ", " << y << ", " << z << ") - "; cout << "(" << myData.a << ", " << myData.b << "), destructed" << endl; } void print(char* prompt) const { cout << "(" << x << ", " << y << ", " << z << ") - "; cout << "(" << myData.a << ", " << myData.b << ")" << prompt << endl; } friend std::ostream& operator<<(std::ostream& os, const MyTest* mytest) { mytest->print(""); return os; } private: MyTest(const MyTest&); MyTest& operator=(const MyTest&); }; struct x_key:composite_key< MyTest, BOOST_MULTI_INDEX_MEMBER(MyTest, int, x) >{}; struct xy_key:composite_key< MyTest, BOOST_MULTI_INDEX_MEMBER(MyTest, int, x), BOOST_MULTI_INDEX_MEMBER(MyTest, int, y) >{}; struct xyz_key:composite_key< MyTest, BOOST_MULTI_INDEX_MEMBER(MyTest, int, x), BOOST_MULTI_INDEX_MEMBER(MyTest, int, y), BOOST_MULTI_INDEX_MEMBER(MyTest, int, z) >{}; struct MyIndex_X_Tag{}; struct MyIndex_XY_Tag{}; struct MyIndex_XYZ_Tag{}; typedef multi_index_container< MyTest*, indexed_by< ordered_non_unique, x_key, composite_key_result_less >, ordered_non_unique, xy_key, composite_key_result_less >, ordered_unique, xyz_key, composite_key_result_less > > >MyContainer_T; typedef nth_index::type MyContainer_X_T; typedef nth_index::type MyContainer_XY_T; typedef nth_index::type MyContainer_XYZ_T; typedef MyContainer_T::index::type MyContainerIndex_X_T; typedef MyContainer_T::index::type::iterator MyContainerIterator_X_T; typedef std::pair MyContainerPair_X_T; typedef MyContainer_T::index::type MyContainerIndex_XY_T; typedef MyContainer_T::index::type::iterator MyContainerIterator_XY_T; typedef std::pair MyContainerPair_XY_T; typedef MyContainer_T::index::type MyContainerIndex_XYZ_T; typedef MyContainer_T::index::type::iterator MyContainerIterator_XYZ_T; typedef std::pair MyContainerPair_XYZ_T; MyContainer_T mycontainer; MyContainer_X_T& mycontainerx = mycontainer; MyContainer_XY_T& mycontainerxy = get<1>(mycontainer); MyContainer_XYZ_T& mycontainerxyz = get<2>(mycontainer); void query_container(int x) { MyContainerIterator_X_T it0, it1; boost::tie(it0, it1) = mycontainerx.equal_range(boost::make_tuple(x)); if (*it0 == *it1) { cout << "("<print(", found"); ++it0; } } void query_container(int x, int y) { MyContainerIterator_XY_T it0, it1; boost::tie(it0, it1) = mycontainerxy.equal_range(boost::make_tuple(x, y)); if (*it0 == *it1) { cout << "("<print(", found"); ++it0; } } void query_container(int x, int y, int z) { MyContainerIterator_XYZ_T it0, it1; boost::tie(it0, it1) = mycontainerxyz.equal_range(boost::make_tuple(x, y, z)); if (*it0 == *it1) { cout << "("<print(", found"); ++it0; } } template void print_container(const MultiIndexContainer& container) { //obtain a reference to the index tagged by Tag const typename boost::multi_index::index::type& indexSet = get(container); typedef typename MultiIndexContainer::value_type value_type; //dump the elements of the index to cout std::copy(indexSet.begin(), indexSet.end(), std::ostream_iterator(cout)); } template void free_container(MultiIndexContainer& container) { typedef typename MultiIndexContainer::value_type value_type; while (!container.empty()) { typename MultiIndexContainer::iterator iter = container.begin(); if (NULL == (*iter)) { container.erase(iter); continue; } value_type pobj = *iter; container.erase(iter); delete pobj; } } void test1() { MyTest *a = new MyTest(1,1,1,10,100); mycontainer.insert(a); MyTest *b = new MyTest(1,1,2,20,200); mycontainer.insert(b); MyTest *c = new MyTest(1,1,3,30,300); mycontainer.insert(c); } void test2() { MyTest *a = new MyTest(1,2,1,40,400); mycontainer.insert(a); MyTest *b = new MyTest(1,2,2,50,500); mycontainer.insert(b); MyTest *c = new MyTest(1,2,3,60,600); mycontainer.insert(c); } void test3() { MyTest *a = new MyTest(1,3,1,70,700); mycontainer.insert(a); MyTest *b = new MyTest(1,3,2,80,800); mycontainer.insert(b); MyTest *c = new MyTest(1,3,3,90,900); mycontainer.insert(c); } void test4() { MyTest *a = new MyTest(2,1,1,110,1000); mycontainer.insert(a); MyTest *b = new MyTest(2,1,2,220,2000); mycontainer.insert(b); MyTest *c = new MyTest(2,1,3,330,3000); mycontainer.insert(c); } void test5() { MyTest *a = new MyTest(2,2,1,440,4000); mycontainer.insert(a); MyTest *b = new MyTest(2,2,2,550,5000); mycontainer.insert(b); MyTest *c = new MyTest(2,2,3,660,6000); mycontainer.insert(c); } void test6() { MyTest *a = new MyTest(2,3,1,770,7000); mycontainer.insert(a); MyTest *b = new MyTest(2,3,2,880,8000); mycontainer.insert(b); MyTest *c = new MyTest(2,3,3,990,9000); mycontainer.insert(c); } void query_test1() { query_container(1); cout<(mycontainer); //cout<(mycontainer); //cout<(mycontainer); cout<

运行结果如下：

 

---

(1, 1, 1) - (10, 100)

 

(1, 1, 2) - (20, 200)

(1, 1, 3) - (30, 300)

(1, 2, 1) - (40, 400)

(1, 2, 2) - (50, 500)

(1, 2, 3) - (60, 600)

(1, 3, 1) - (70, 700)

(1, 3, 2) - (80, 800)

(1, 3, 3) - (90, 900)

(2, 1, 1) - (110, 1000)

(2, 1, 2) - (220, 2000)

(2, 1, 3) - (330, 3000)

(2, 2, 1) - (440, 4000)

(2, 2, 2) - (550, 5000)

(2, 2, 3) - (660, 6000)

(2, 3, 1) - (770, 7000)

(2, 3, 2) - (880, 8000)

(2, 3, 3) - (990, 9000)

 

// 查询索引 x=1 的所有数据

(1, 2, 1) - (40, 400), found

(1, 2, 2) - (50, 500), found

(1, 2, 3) - (60, 600), found

(1, 1, 1) - (10, 100), found

(1, 1, 2) - (20, 200), found

(1, 1, 3) - (30, 300), found

(1, 3, 1) - (70, 700), found

(1, 3, 2) - (80, 800), found

(1, 3, 3) - (90, 900), found

 

// 查询索引 x=2 的所有数据

(2, 1, 1) - (110, 1000), found

(2, 1, 2) - (220, 2000), found

(2, 1, 3) - (330, 3000), found

(2, 3, 1) - (770, 7000), found

(2, 3, 2) - (880, 8000), found

(2, 3, 3) - (990, 9000), found

(2, 2, 1) - (440, 4000), found

(2, 2, 2) - (550, 5000), found

(2, 2, 3) - (660, 6000), found

 

// 查询索引 x=3 的所有数据

(3) - not found

 

// 查询索引 的所有数据

(1, 1, 1) - (10, 100), found

(1, 1, 2) - (20, 200), found

(1, 1, 3) - (30, 300), found

// 查询索引 的所有数据

(1, 2, 1) - (40, 400), found

(1, 2, 2) - (50, 500), found

(1, 2, 3) - (60, 600), found

// 查询索引 的所有数据

(1, 3, 1) - (70, 700), found

(1, 3, 2) - (80, 800), found

(1, 3, 3) - (90, 900), found

// 查询索引 的所有数据

(1, 4) - not found

 

// 查询索引 的所有数据

(2, 1, 1) - (110, 1000), found

(2, 1, 2) - (220, 2000), found

(2, 1, 3) - (330, 3000), found

// 查询索引 的所有数据

(2, 2, 1) - (440, 4000), found

(2, 2, 2) - (550, 5000), found

(2, 2, 3) - (660, 6000), found

// 查询索引 的所有数据

(2, 3, 1) - (770, 7000), found

(2, 3, 2) - (880, 8000), found

(2, 3, 3) - (990, 9000), found

// 查询索引 的所有数据

(2, 4) - not found

 

// 查询索引 ~ 的所有数据

(1, 1, 1) - (10, 100), found

(1, 1, 2) - (20, 200), found

(1, 1, 3) - (30, 300), found

(1, 2, 1) - (40, 400), found

(1, 2, 2) - (50, 500), found

(1, 2, 3) - (60, 600), found

(1, 3, 1) - (70, 700), found

(1, 3, 2) - (80, 800), found

(1, 3, 3) - (90, 900), found

 

(2, 1, 1) - (110, 1000), found

(2, 1, 2) - (220, 2000), found

(2, 1, 3) - (330, 3000), found

(2, 2, 1) - (440, 4000), found

(2, 2, 2) - (550, 5000), found

(2, 2, 3) - (660, 6000), found

(2, 3, 1) - (770, 7000), found

(2, 3, 2) - (880, 8000), found

(2, 3, 3) - (990, 9000), found

 

// 查询索引 等的所有数据

(2, 3, 4) - not found

(3, 3, 3) - not found

 

// 释放 container

(1, 2, 1) - (40, 400), destructed

(1, 2, 2) - (50, 500), destructed

(1, 2, 3) - (60, 600), destructed

(1, 1, 1) - (10, 100), destructed

(1, 1, 2) - (20, 200), destructed

(1, 1, 3) - (30, 300), destructed

(1, 3, 1) - (70, 700), destructed

(1, 3, 2) - (80, 800), destructed

(1, 3, 3) - (90, 900), destructed

(2, 1, 1) - (110, 1000), destructed

(2, 1, 2) - (220, 2000), destructed

(2, 1, 3) - (330, 3000), destructed

(2, 3, 1) - (770, 7000), destructed

(2, 3, 2) - (880, 8000), destructed

(2, 3, 3) - (990, 9000), destructed

(2, 2, 1) - (440, 4000), destructed

(2, 2, 2) - (550, 5000), destructed

(2, 2, 3) - (660, 6000), destructed

 

---

本系列的所有例子均以上述数据为例。

 

注释为笔者加入。

 

Reference

./l ibs/multi_index/doc/index.html

./ libs/multi_index/doc/tutorial/key_extraction.html#composite_keys

./ libs/multi_index/doc/examples.html#example7

其中， . 为 Boost 安装路径。

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