构造函数用explict并初始化std::runtime_err, 有问题。

sybaselu

有三个文件sqlite_db.h/.cpp/, main.cpp

1. 
   
2. #ifndef SQLITE_DB_H
   
3. #define SQLITE_DB_H
   
4. 
   
5. #include <string>
   
6. #include <map>
   
7. #include <vector>
   
8. #include "sqlite.h"
   
9. 
   
10. using namespace std;
    
11. 
    
12. class sqlite_exception : public std::runtime_error
    
13. {
    
14.   public:
    
15.     explicit sqlite_exception( const std::string &what )
    
16.                :std::runtime_error( what )
    
17.    { }
    
18. };
    
19. 
    
20. 
    
21. typedef std::map<std::string,std::string> sqlite_fields;
    
22. typedef std::vector<sqlite_fields> sqlite_result;
    
23. 
    
24. class sqlite_db
    
25. {
    
26.   private:
    
27.     sqlite* db_;
    
28.     static int sqlite_callback(void *param,int colcount,char **cols,char **colnames);
    
29.   public:
    
30.     sqlite_db():db_(NULL){}
    
31.     virtual ~sqlite_db(){if(db_)close();}
    
32.     const char *version()const{return SQLITE_VERSION;}
    
33.     void open(const std::string& db);
    
34.     void close();
    
35.     sqlite_result exec_sql(const std::string& query);
    
36.     void exec_dml(const std::string& query);
    
37. };
    
38. 
    
39. #endif
    

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编译如下：

1. 
   
2. [root@root DB]# g++ -I/usr/local/include -c sqlite_db.cpp -o sqlite_db.o
   
3. In file included from sqlite_db.cpp:1:
   
4. sqlite_db.h:12: error: expected class-name before '{' token
   
5. sqlite_db.h: In constructor `sqlite_exception::sqlite_exception(const std::string&)':
   
6. sqlite_db.h:14: error: expected class-name before '(' token
   
7. [root@root DB]#
   

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x11

public class

rickxbx

headfile "stdexcept" ??

sybaselu

where? I have tried for serval times for adding "public clas" to place in where should be added, but in vail eventually.

rickxbx

不需要 stdexcept 头文件吗?

sybaselu

已经加上<stdexcept>。

1. 
   
2. [root@root DB]# g++ -I/usr/local/include -c sqlite_db.cpp -o sqlite_db.o
   
3. In file included from sqlite_db.cpp:1:
   
4. sqlite_db.h:14: error: expected `,' or `...' before '&' token
   
5. sqlite_db.h:14: error: ISO C++ forbids declaration of `string' with no type
   
6. sqlite_db.h: In constructor `sqlite_exception::sqlite_exception(int)':
   
7. sqlite_db.h:15: error: no matching function for call to `std::runtime_error::runtime_error(<unknown type>)'
   
8. 下面是sqlite_db.cpp的错误，都是因为sqlite_execption中转化错误或函数不匹配，所以没有列出来。
   

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x11

呵呵，我以为继承要写成class sqlite_exception : public class std::runtime_error
不过发现不用

rickxbx

Post by sybaselu
已经加上<stdexcept>。

1. 
   
2. [root@root DB]# g++ -I/usr/local/include -c sqlite_db.cpp -o sqlite_db.o
   
3. In file included from sqlite_db.cpp:1:
   
4. sqlite_db.h:14: error: expected `,' or `...' before '&' token
   
5. sqlite_db.h:14: error: ISO C++ forbids declaration of `string' with no type
   
6. sqlite_db.h: In constructor `sqlite_exception::sqlite_exception(int)':
   
7. sqlite_db.h:15: error: no matching function for call to `std::runtime_error::runtime_error(<unknown type>)'
   
8. 下面是sqlite_db.cpp的错误，都是因为sqlite_execption中转化错误或函数不匹配，所以没有列出来。
   

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感觉怪怪的, 全部帖上来看看吧....

rickxbx

Post by x11
呵呵，我以为继承要写成class sqlite_exception : public class std::runtime_error
不过发现不用

兄弟在上海?

sybaselu

Ok , here we go, go throughly the whole source code ：
sqlite_db.h//

1. 
   
2. #ifndef SQLITE_DB_H
   
3. #define SQLITE_DB_H
   
4. 
   
5. #include <string>
   
6. #include <map>
   
7. #include <vector>
   
8. #include "sqlite.h"
   
9. #include <stdexcept>
   
10. 
    
11. 
    
12. class sqlite_exception : public std::runtime_error
    
13. {
    
14. public:
    
15.     explicit sqlite_exception(const string& what) : std::runtime_error( what )
    
16.     {}
    
17. };
    
18. 
    
19. typedef std::map<std::string,std::string> sqlite_fields;
    
20. typedef std::vector<sqlite_fields> sqlite_result;
    
21. 
    
22. class sqlite_db
    
23. {
    
24.   private:
    
25.     sqlite* db_;
    
26.     static int sqlite_callback(void *param,int colcount,char **cols,char **colnames);
    
27.   public:
    
28.     sqlite_db():db_(NULL){}
    
29.     virtual ~sqlite_db(){if(db_)close();}
    
30.     const char *version()const{return SQLITE_VERSION;}
    
31.     void open(const std::string& db);
    
32.     void close();
    
33.     sqlite_result exec_sql(const std::string& query);
    
34.     void exec_dml(const std::string& query);
    
35. };
    
36. 
    
37. #endif
    
38. 
    

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sqlite_db.cpp//

1. 
   
2. #include "sqlite_db.h"
   
3. 
   
4. void sqlite_db::open(const std::string& db)
   
5. {
   
6.   if(db_)close();
   
7.   char *errmsg = NULL;
   
8.   db_ = sqlite_open(db.c_str(),0,&errmsg);
   
9.   if(db_ == 0)
   
10.   {
    
11.     std::string error(errmsg);
    
12.     sqlite_freemem(errmsg);
    
13.     throw sqlite_exception(error);
    
14.   }
    
15.   if(errmsg != NULL) sqlite_freemem(errmsg);
    
16. }
    
17. 
    
18. void sqlite_db::close()
    
19. {
    
20.   if(db_)sqlite_close(db_);
    
21.   db_ = NULL;
    
22. }
    
23. 
    
24. sqlite_result sqlite_db::exec_sql(const std::string& query)
    
25. {
    
26.   if(!db_)throw sqlite_exception("No opened database");
    
27.   char* errmsg = NULL;
    
28.   sqlite_result result;
    
29.   int res = sqlite_exec(db_,query.c_str(),sqlite_callback,(void*)&result,&errmsg);
    
30.   if(res != SQLITE_OK)
    
31.   {
    
32.     std::string error(errmsg);
    
33.     sqlite_freemem(errmsg);
    
34.     throw sqlite_exception(error);
    
35.   }
    
36.   if(errmsg != NULL) sqlite_freemem(errmsg);
    
37.   return result;
    
38. }
    
39. 
    
40. void sqlite_db::exec_dml(const std::string& query)
    
41. {
    
42.   if(!db_)throw sqlite_exception("No opened database");
    
43.   char* errmsg = NULL;
    
44.   int res = sqlite_exec(db_,query.c_str(),sqlite_callback,(void*)NULL,&errmsg);
    
45.   if(res != SQLITE_OK)
    
46.   {
    
47.     std::string error(errmsg);
    
48.     sqlite_freemem(errmsg);
    
49.     throw sqlite_exception(error);
    
50.   }
    
51.   if(errmsg != NULL) sqlite_freemem(errmsg);
    
52. }
    
53. 
    
54. int sqlite_db::sqlite_callback(void *param,int colcount,char **cols,char **colnames)
    
55. {
    
56.   sqlite_result* result = reinterpret_cast<sqlite_result*>(param);
    
57.   sqlite_fields f;
    
58.   for(int i = 0;i < colcount;++i)
    
59.   {
    
60.     f[colnames[i]] = cols[i];
    
61.   }
    
62.   result->push_back(f);
    
63.   return 0;
    
64. }
    
65. 
    

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sqlite_db_main.cpp//

1. 
   
2. #include <iostream>
   
3. #include <string>
   
4. #include <conio.h>
   
5. 
   
6. #include "sqlite_db.h"
   
7. 
   
8. int main()
   
9. {
   
10.   sqlite_db db;
    
11.   try
    
12.   {
    
13.     db.open("test.db");
    
14.     std::cout<<"sqlite version = "<<db.version()<<std::endl;
    
15. 
    
16.     // First we create the table
    
17.     std::string query("CREATE TABLE customers (Id integer,Name varchar(16)," \
    
18.          "City varchar(16));");
    
19.     db.exec_dml(query);
    
20. 
    
21.     // Add some records to the table
    
22.     query = "INSERT INTO customers VALUES (2004001,'Smith','Brussels');";
    
23.     db.exec_dml(query);
    
24.     query = "INSERT INTO customers VALUES (2004002,'Powell','London');";
    
25.     db.exec_dml(query);
    
26.     query = "INSERT INTO customers VALUES (2004003,'Brown','New-York');";
    
27.     db.exec_dml(query);
    
28. 
    
29.     // Read the records back
    
30.     query = "SELECT * FROM customers;";
    
31.     sqlite_result res = db.exec_sql(query);
    
32.     for(sqlite_result::size_type i = 0;i < res.size();++i)
    
33.     {
    
34.       sqlite_fields row = res[i];
    
35.       for(sqlite_fields::const_iterator it = row.begin();it != row.end();++it)
    
36.       {
    
37.         std::cout<<(*it).first<<" = "<<(*it).second<<std::endl;
    
38.       }
    
39.       std::cout<<std::endl;
    
40.     }
    
41.   }
    
42.   catch(sqlite_exception &ex)
    
43.   {
    
44.     std::cout<<ex.what()<<std::endl;
    
45.   }
    
46. 
    
47.   getch();
    
48.   return 0;
    
49. }
    
50.                                                                            
    

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谢过先了，想用封装过的sqite3做点东东。