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Mysql必讀介紹一個(gè)針對(duì)C++程序的MySQL訪問(wèn)庫(kù)soci

作者：VEPHP   時(shí)間 2017-10-01

《Mysql必讀介紹一個(gè)針對(duì)C++程序的MySQL訪問(wèn)庫(kù)soci》要點(diǎn)：
本文介紹了Mysql必讀介紹一個(gè)針對(duì)C++程序的MySQL訪問(wèn)庫(kù)soci，希望對(duì)您有用。如果有疑問(wèn)，可以聯(lián)系我們。

一直以來(lái),筆者都在不停尋找一種更人性化的數(shù)據(jù)庫(kù)訪問(wèn)方式(并不是說(shuō)默認(rèn)的方式不好,而是有時(shí)候的確在模塊化設(shè)計(jì)中不太方便).
后來(lái)有幸在php中找到codeigniter的ActiveReord,詳細(xì)參考這篇文章: 抽離CodeIgniter的數(shù)據(jù)庫(kù)訪問(wèn)類!
然而c++卻始終用著最原始的方式,昨天趁著項(xiàng)目要用的機(jī)會(huì),在網(wǎng)上搜索了好久,總算讓我找到兩套c++的數(shù)據(jù)庫(kù)訪問(wèn)框架:MYSQL數(shù)據(jù)庫(kù)

???soci
???litesqlMYSQL數(shù)據(jù)庫(kù)

兩套代碼我都拿下來(lái)看了一下,litesql實(shí)現(xiàn)了一套完整的代碼自動(dòng)生成,功能強(qiáng)大,但是也很重；soci相對(duì)要輕量,但是同樣也實(shí)現(xiàn)了數(shù)據(jù)結(jié)構(gòu)到數(shù)據(jù)庫(kù)表的映射.本人還是比較喜歡輕量的東西,所以最終選擇了soci.經(jīng)過(guò)這兩天的試用,感覺(jué)非常不錯(cuò).MYSQL數(shù)據(jù)庫(kù)

官方的文檔也很詳細(xì),所以這里就用我寫的單元測(cè)試代碼來(lái)做一下簡(jiǎn)單的講解:
首先創(chuàng)建庫(kù)表:
MYSQL數(shù)據(jù)庫(kù)

create database soci;
CREATE TABLE `tb_test` (
 `id` int(11) NOT NULL auto_increment,
 `name` varchar(32) default "",
 `sex` int(11) default 0,
 PRIMARY KEY (`id`),
 UNIQUE KEY `name` (`name`)
);
 
create database soci;
CREATE TABLE `tb_test` (
 `id` int(11) NOT NULL auto_increment,
 `name` varchar(32) default "",
 `sex` int(11) default 0,
 PRIMARY KEY (`id`),
 UNIQUE KEY `name` (`name`)
);

1.簡(jiǎn)單的select單條記錄
MYSQL數(shù)據(jù)庫(kù)

TEST(soci,select_one)
{
  try
  {
    session sql(mysql, "host=localhost db=soci user=dantezhu");
    indicator ind;
    string name = "dandan";
    int sex;
    sql << "select sex from tb_test where name = :name",
      into(sex, ind), use(name);
    ASSERT_EQ(ind, i_ok) << name;
  }
  catch (exception const &e)
  {
    FAIL()<<e.what();
  }
}
 
TEST(soci,select_one)
{
  try
  {
    session sql(mysql, "host=localhost db=soci user=dantezhu");
    indicator ind;
 
    string name = "dandan";
    int sex;
    sql << "select sex from tb_test where name = :name",
      into(sex, ind), use(name);
 
    ASSERT_EQ(ind, i_ok) << name;
  }
  catch (exception const &e)
  {
    FAIL()<<e.what();
  }
}

select的結(jié)果,如果成功則ind會(huì)為i_ok,同值sex被賦值；如果失敗則反之MYSQL數(shù)據(jù)庫(kù)

2.簡(jiǎn)單的select多條記錄
MYSQL數(shù)據(jù)庫(kù)

TEST(soci,select_multi2)
{
  try
  {
    session sql(mysql, "db=soci user=dantezhu");
    indicator ind;
    int count;
    sql << "select count(*) from tb_test", into(count, ind);
    ASSERT_EQ(ind, i_ok) << count;
    if (count == 0)
    {
      SUCCEED();
      return;
    }
    int sex = 1;
    vector<string> vec_name(count);
    vector<int> vec_sex(count);
    sql << "select name,sex from tb_test where sex = :sex",
      into(vec_name), into(vec_sex), use(sex);
  }
  catch (exception const &e)
  {
    FAIL()<<e.what();
  }
}
 
TEST(soci,select_multi2)
{
  try
  {
    session sql(mysql, "db=soci user=dantezhu");
    indicator ind;
 
    int count;
    sql << "select count(*) from tb_test", into(count, ind);
    ASSERT_EQ(ind, i_ok) << count;
 
    if (count == 0)
    {
      SUCCEED();
      return;
    }
 
    int sex = 1;
    vector<string> vec_name(count);
    vector<int> vec_sex(count);
    sql << "select name,sex from tb_test where sex = :sex",
      into(vec_name), into(vec_sex), use(sex);
  }
  catch (exception const &e)
  {
    FAIL()<<e.what();
  }
}

與select單條記錄唯一的區(qū)別即,into()的參數(shù)是一個(gè)vector.其實(shí)用多個(gè)vector這種方式并不是一個(gè)很好的選擇,后面會(huì)介紹基于數(shù)據(jù)結(jié)構(gòu)的方式.MYSQL數(shù)據(jù)庫(kù)

3.簡(jiǎn)單的insert
MYSQL數(shù)據(jù)庫(kù)

TEST(soci,insert_exist)
{
  try
  {
    session sql(mysql, "db=soci user=dantezhu");
    string name = "dandan";
    int sex = 1;
    sql << "insert into tb_test(name, sex) values(:name, :sex)",
      use(name), use(sex);
  }
  catch (exception const &e)
  {
    SUCCEED()<<e.what();
  }
}
 
TEST(soci,insert_exist)
{
  try
  {
    session sql(mysql, "db=soci user=dantezhu");
 
    string name = "dandan";
    int sex = 1;
 
    sql << "insert into tb_test(name, sex) values(:name, :sex)",
      use(name), use(sex);
  }
  catch (exception const &e)
  {
    SUCCEED()<<e.what();
  }
}

insert,update,delete都有兩個(gè)同樣的問(wèn)題:
a)affect_rows(操作的行數(shù))沒(méi)有辦法返回
b)操作的id無(wú)法知道,尤其對(duì)于insert的主鍵是自增的情況下,無(wú)法知道插入的主鍵的值是多少.MYSQL數(shù)據(jù)庫(kù)

update和delete都與insert相似,這里就不再多說(shuō).MYSQL數(shù)據(jù)庫(kù)

接下來(lái)是這個(gè)框架的很重要的一個(gè)特性,即數(shù)據(jù)庫(kù)表與數(shù)據(jù)結(jié)構(gòu)綁定：MYSQL數(shù)據(jù)庫(kù)

首先我們需要定義一個(gè)結(jié)構(gòu)體,并告知soci怎么讓列名和數(shù)據(jù)結(jié)構(gòu)的字段對(duì)應(yīng)起來(lái):
MYSQL數(shù)據(jù)庫(kù)

struct Person
{
  int id;
  std::string name;
  int sex;
};
namespace soci
{
  template<> struct type_conversion<Person>
  {
    typedef values base_type;
    static void from_base(values const & v, indicator /* ind */, Person & p)
    {
      p.id = v.get<int>("id");
      p.name = v.get<std::string>("name");
      p.sex = v.get<int>("sex");
    }
    static void to_base(const Person & p, values & v, indicator & ind)
    {
      v.set("id", p.id);
      v.set("name", p.name);
      v.set("sex", p.sex);
      ind = i_ok;
    }
  };
}
 
struct Person
{
  int id;
  std::string name;
  int sex;
};
 
namespace soci
{
  template<> struct type_conversion<Person>
  {
    typedef values base_type;
    static void from_base(values const & v, indicator /* ind */, Person & p)
    {
      p.id = v.get<int>("id");
      p.name = v.get<std::string>("name");
      p.sex = v.get<int>("sex");
    }
    static void to_base(const Person & p, values & v, indicator & ind)
    {
      v.set("id", p.id);
      v.set("name", p.name);
      v.set("sex", p.sex);
      ind = i_ok;
    }
  };
}

關(guān)于
MYSQL數(shù)據(jù)庫(kù)

template<> struct type_conversion<Person>
 
template<> struct type_conversion<Person>

這里,官方的文檔是是有誤的,我查了好長(zhǎng)時(shí)間,按照上面的寫法來(lái)寫即可.MYSQL數(shù)據(jù)庫(kù)

1.用數(shù)據(jù)結(jié)構(gòu)來(lái)select
MYSQL數(shù)據(jù)庫(kù)

TEST(soci,select_obj_one)
{
  try
  {
    session sql(mysql, "db=soci user=dantezhu");
    indicator ind;
    int count;
    sql << "select count(*) from tb_test", into(count, ind);
    ASSERT_EQ(ind, i_ok) << count;
    string name = "dandan";
    Person p;
    sql << "select id,name,sex from tb_test where name = :name",
      into(p, ind), use(name);
    ASSERT_EQ(ind, i_ok) << name;
    if (sql.got_data())
    {
      cout<< p.id 
        << "," 
        << p.name 
        << "," 
        << p.sex 
        << endl;
    }
  }
  catch (exception const &e)
  {
    FAIL()<<e.what();
  }
}
 
TEST(soci,select_obj_one)
{
  try
  {
    session sql(mysql, "db=soci user=dantezhu");
    indicator ind;
 
    int count;
    sql << "select count(*) from tb_test", into(count, ind);
    ASSERT_EQ(ind, i_ok) << count;
 
    string name = "dandan";
    Person p;
    sql << "select id,name,sex from tb_test where name = :name",
      into(p, ind), use(name);
 
    ASSERT_EQ(ind, i_ok) << name;
 
    if (sql.got_data())
    {
      cout<< p.id 
        << "," 
        << p.name 
        << "," 
        << p.sex 
        << endl;
    }
 
  }
  catch (exception const &e)
  {
    FAIL()<<e.what();
  }
}

2.用數(shù)據(jù)結(jié)構(gòu)來(lái)進(jìn)行insert
MYSQL數(shù)據(jù)庫(kù)

TEST(soci,insert_obj_noexist)
{
  try
  {
    session sql(mysql, "db=soci user=dantezhu");
    Person p = {
      0,
      "niuniu",
      2
    };
    sql << "insert into tb_test(name, sex) values(:name, :sex)",
      use(p);
  }
  catch (exception const &e)
  {
    FAIL()<<e.what();
  }
}
 
TEST(soci,insert_obj_noexist)
{
  try
  {
    session sql(mysql, "db=soci user=dantezhu");
 
    Person p = {
      0,
      "niuniu",
      2
    };
 
    sql << "insert into tb_test(name, sex) values(:name, :sex)",
      use(p);
  }
  catch (exception const &e)
  {
    FAIL()<<e.what();
  }
}

整個(gè)就是這樣~~下面是文中代碼文件的下載路徑：
http://code.google.com/p/vimercode/source/browse/#svn%2Ftrunk%2Fsoci_testMYSQL數(shù)據(jù)庫(kù)

另外,雖然python下的mysql訪問(wèn)也算比較簡(jiǎn)單,但還是想知道是否有更Pythonic的庫(kù)或接口,如果有朋友知道,歡迎不吝告知.
MYSQL數(shù)據(jù)庫(kù)

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