用c语言动态操作sqilite3数据库

本文为转载，转载地址为：

http://www.cnblogs.com/elect-fans/archive/2012/08/04/2622467.html

/* 项目名称：用c语言动态操作sqilite3数据库 
* 项目成员：张双喜 
* 编译环境：gcc 
* 项目功能： 
* 1、动态创建表 
* 2、动态实现对表的基本操作（增、删、改、查） 
* 3、清空表数据、删除表（附加功能） 
* 项目总结： 
* 1、涉及的技术： 
* 1、int sqlite3_exec(sqlite3*, const char *sql, sqlite_callback, void*, char**); 
* 欲实现动态操作数据库，必须动态构造sql语句，构造sql语句可以用strcat函数，逐步拼接，直至完整构造出sql语句。 
* 2、欲实现简单菜单选项效果，须分离出实现每个子功能的函数，在switch中，选择的调用 
* 3、 
* 2、意外收获： 
* 1、想输入一条带有空格的字符串，不能用scanf函数，应为scanf函数遇到空格、换行、回车自动结束输入，所以scanf不能达到预期效果 
* ，解决该问题可以使用gets函数，但是gets是个危险函数，c语言不提倡使用，在使用gets函数前，一定要清空缓冲区，否则。会出现 
* 意想不到的输入结果，这就是先前没有清空缓冲区造成的。 
* 2、linux c 清空缓冲区的问题： 
* 个人见解： 
* 经测试，linux c 使用fflush(stdin)无法清空缓冲区，使用fflush(stdin)后，再使用gets函数，gets还是会从缓冲区中读取东西， 
* 因为缓冲区经fflush(stdin)没有被清空； 
* 经过在网上找资料，得知setbuf(stdin, NULL);这样一个函数，经测试，清理缓冲区成功。 
* 简言之：linux c 清空缓冲区的函数：setbuf(stdin, NULL); 
* 3、编程中问题及其解决方法： 
* 1、更新数据库update正确使用方法： 
* update table_name set name = 'new_name', sex = 'new_sex' where id = id_val; //是正确的 
* 上句中的,不能换成and， 
* 即： 
* update table_name set name = 'new_name' and sex = 'new_sex' where id = id_val; //是错误的 
* 2、字符串的问题： 
* char * p = "hello world!"; //该字符串是只读的不能修改字符串，不能改写，不能strcat(p, "jack"); 
* char str[] = "hello world!" //这样可以通过指针或不通过指针对字符串进行任意操作 
* char *p; 
* p = str; 
* 3、字符串清理零： 
* char str[10]; 
* memset(str, 0,sizeof(str)); 
* 张双喜 
* v1.0 
* 2010.9.29 14:39 
* update 1 
* 1、增加了一个测试表test_table，解决了，每次对操作数据库必须首先建立一个表的bug 
* 2、增加了确认退出功能 
* 
* 张双喜 
* v2.0 
* 2010.9.30 9:40 
* 
* */

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include "sqlite3.h"

 /*该结构体是方便对表内数据操作*/

 typedef struct table_column
 {
     char column_name[100];        //列名
     char column_type[200];        //列的数据类型
 }COLUMN;

 void db_create(sqlite3 * db, char * pTable_name, int column_num
 , COLUMN column[], int * create_flag);
 int rscallback(void * p, int column, char ** column_val
 ,char ** column_name);
 void db_show(sqlite3 * db, char * pTable_name);
 void db_insert(sqlite3 * db, char * pTable_name, int column_num
 , COLUMN column[], int * test_flag, int * create_flag);
 void db_update(sqlite3 * db, char * pTable_name, int column_Num
 , COLUMN column[], int * test_flag, int * create_flag);
 void db_delete(sqlite3 * db, char * pTable_name);
 void db_empty(sqlite3 * db, char * pTable_name);
 void db_drop(sqlite3 * db, char *pTable_name, int * test_flag
 , int * create_flag);
 void db_test(sqlite3 * db, char * pTable_name, int ** test_flag);
 void db_flag(sqlite3 * db, int * create_flag, int * test_flag
 , char * pTable_name);
 void db_reset_table_name(sqlite3 * db, char * pTable_name);

 int main(int argc, char* argv[])
 {
     sqlite3 * db;
     int empty = 1;
     int ret = 0;
     int create_flag = 1;
     int test_flag = 1;
     int test_flag_create = 1;
     char c = 'n';
     char * errmsg = NULL;
     int choice = -1;
     char table_name[20];
     char * pTable_name;
     int column_num;
     int i;
     COLUMN column[10];
     pTable_name = table_name;
     strcpy(pTable_name, "test_table");

     ret = sqlite3_open("student.db", &db);
     if(ret != SQLITE_OK)
     {
         perror("slqite3_open");
         exit(1);
     }

     while(choice != 0)
     {
 printf("please input your choise:/n");
 printf("-------------------------------------/n");
 printf("|0.exit|1.create|2.show|3.insert|4.update|5.delete|6.empty|7.drop|/n");
 printf("-------------------------------------/n");
         scanf("%d", &choice);

         switch(choice)
         {
             case 0:
 printf("you choise leave, y or n?/n");
                     setbuf(stdin, NULL);
                     scanf("%c", &c);
                     setbuf(stdin, NULL);
                     if(c == 'y')
                     {
                         if(test_flag == 0)
                         {
 db_drop(db, "test_table", &test_flag, &create_flag);
                         }

                         printf("goodbye!/n");

                         sqlite3_close(db);

                         return 0;
                     }
                     else
                     {
                         choice = -1;
                     }

                     break;

             case 1:
 printf("we will create a table for you, please input the name of your table:/n");
 scanf("%s",pTable_name);
 printf("please input the number of column:/n");
 scanf("%d", &column_num);
 printf("please input column_name column_type:/n");

 for(i = 0; i < column_num; i++)
   scanf("%s %s", column[i].column_name, column[i].column_type);

 db_create(db, table_name, column_num, column, &create_flag);
                     break;
             case 2:
 db_flag(db, &create_flag, &test_flag, table_name);
 db_show(db, table_name);
                     break;

             case 3:
 db_flag(db, &create_flag, &test_flag, table_name);
 db_insert(db, table_name, column_num, column, &test_flag, &create_flag);
                     break;
             case 4:
 db_flag(db, &create_flag, &test_flag, table_name);
 db_update(db, table_name, column_num, column, &test_flag, &create_flag);
                     break;
             case 5:
                     db_flag(db, &create_flag, &test_flag, table_name);
                     db_delete(db, table_name);
                     break;
             case 6:
                     db_flag(db, &create_flag, &test_flag, table_name);
                     db_empty(db, table_name);
                     break;
             case 7:
                     db_flag(db, &create_flag, &test_flag, table_name);
                     db_drop(db, table_name, &test_flag, &create_flag);
                     break;
             default:
                     printf("your choice is not exist!/n");
                     break;

         }

     }

     sqlite3_close(db);

     return 0;
 }

 void db_flag(sqlite3 * db, int * create_flag, int * test_flag
 , char * pTable_name)
 {
     if(create_flag)
     {
         if(*test_flag)
         {
             db_test(db, pTable_name, &test_flag);
         }

     }

     return;
 }

 void db_test(sqlite3 * db, char * pTable_name, int ** test_flag)
 {
     int ret;
     char * errmsg;

     **test_flag = 0;

     printf("because you have not create a table,so we create　\
 a test_table table for you!/n");
     ret = sqlite3_exec(db, "create table test_table (id integer primary key \
 autoincrement, name text, sex text, age integer);", NULL, NULL, &errmsg);
     if(ret != SQLITE_OK)
     {
         printf("error:%d:%s/n", ret, errmsg);
         exit(1);
     }
     ret = sqlite3_exec(db, "insert into test_table (name, sex, age) values \
 ('zsx', 'm', 23);",NULL ,NULL, &errmsg);
     if(ret != SQLITE_OK)
     {
         printf("error:%d:%s/n", ret, errmsg);
         exit(1);
     }

     return;
 }

 void db_create(sqlite3 * db, char * pTable_name, int column_num
 , COLUMN column[], int * create_flag)
 {
     int ret, i;
     char * errmsg = NULL;
     char sql[200];
     char * pSql;

     *create_flag = 0;

     pSql = sql;

     strcpy(pSql, "create table ");

     strcat(pSql, pTable_name);

     strcat(pSql, "(");

     strcat(pSql, column[0].column_name);
     strcat(pSql, " ");
     strcat(pSql, column[0].column_type);
     strcat(pSql, " primary key autoincrement");
     strcat(pSql, ", ");

     for(i = 1; i < column_num-1; i++)
     {
         strcat(pSql, column[i].column_name);
         strcat(pSql, " ");
         strcat(pSql, column[i].column_type);
         strcat(pSql, ", ");
     }

     strcat(pSql, column[column_num-1].column_name);
     strcat(pSql, " ");
     strcat(pSql, column[column_num-1].column_type);
     strcat(pSql, ");");

     printf("/nsqlite > %s/n/n",pSql);

     ret = sqlite3_exec(db, pSql, NULL, NULL, &errmsg);
     if(ret != SQLITE_OK)
     {
          printf("error:%d:%s/n", ret, errmsg);
          exit(1);
     }

     return;
 }

 int rscallback(void * p, int column, char ** column_val,char ** column_name)
 {
     int i;
     *(int *)p = 0;

     for(i = 0; i < column; i++)
     {
         printf("%s > %s/t/t",column_name[i], column_val[i]);
     }
     printf("/n");
     return 0;
 }

 void db_show(sqlite3 * db, char * pTable_name)
 {
     int ret = 0;
     char * errmsg = NULL;
     int empty = 1;
     char sql[200];
     char * pSql;

     pSql = sql;

     strcpy(pSql, "select * from ");
     strcat(pSql, pTable_name);
     strcat(pSql, ";");
     printf("/nsqlite > %s/n/n", pSql);

     ret = sqlite3_exec(db, pSql, rscallback, &empty, &errmsg);
     if(ret != SQLITE_OK)
     {
         printf("error:%d:%s/n", ret, errmsg);
         exit(1);
     }

     if(empty)
     {
         printf("the table is empty!/n");
     }

     printf("/n");
     return;
 }

 void db_insert(sqlite3 * db, char * pTable_name, int column_num
 , COLUMN column[], int * test_flag, int * create_flag)
 {
     int ret = 0;
     char * errmsg = NULL;
     char sql[200];
     char * pSql;
     char tmp[20];
     int i;
     char test_val[100];

     pSql = sql;
     strcpy(pSql, "insert into ");
     strcat(pSql, pTable_name);
     strcat(pSql, "(");

     if((*test_flag == 0) && (*create_flag))
     {
         strcat(pSql, " name, ");
         strcat(pSql, "sex, ");
         strcat(pSql, "age ) ");
         strcat(pSql, "values (");

         printf("please input name:/n");
         scanf("%s", test_val);
         strcat(pSql, " /'");
         strcat(pSql, test_val);
         strcat(pSql, "/', ");
         printf("please input sex:/n");
         scanf("%s", test_val);
         strcat(pSql, "/'");
         strcat(pSql, test_val);
         strcat(pSql,"/', ");
         printf("please input age:/n");
         scanf("%s",test_val);
         strcat(pSql,test_val);
         strcat(pSql, ");");
     }
     if(*create_flag == 0)
     {
         for(i = 1; i < column_num-1; i++)
         {
             strcat(pSql, column[i].column_name);
             strcat(pSql, ", ");
         }

         strcat(pSql, column[column_num-1].column_name);
         strcat(pSql, ") ");
         strcat(pSql, "values(");
         for(i = 1; i < column_num-1; i++)
         {
             printf("please input %s/n",column[i].column_name);
             if(strcmp(column[i].column_type,"text") == 0)
             {
                 strcat(pSql, "/'");
                 memset(tmp, 0, sizeof(tmp));
                 scanf("%s",tmp);
                 strcat(pSql, tmp);
                 strcat(pSql,"/'");
                 strcat(pSql, ",");
             }
             else
             {
                 memset(tmp,0,sizeof(tmp));
                 scanf("%s",tmp);
                 strcat(pSql, tmp);
                 strcat(pSql,",");
                 strcat(pSql," ");
             }
         }
         printf("please input %s/n",column[column_num-1].column_name);
         if(strcmp(column[column_num-1].column_type, "text") == 0)
         {
             scanf("%s",tmp);
             strcat(pSql, "/'");
             strcat(pSql, tmp);
             strcat(pSql, "/'");
             strcat(pSql, ");");
         }
         else
         {
             scanf("%s",tmp);
             strcat(pSql, tmp);
             strcat(pSql, ");");
         }
     }
     printf("/nsqlite > %s/n/n", pSql);

     ret = sqlite3_exec(db, pSql, NULL, NULL, &errmsg);
     if(ret != SQLITE_OK)
     {
         printf("error:%d:%s/n", ret, errmsg);
         exit(1);
     }

     return;
 }

 void db_update(sqlite3 * db, char * pTable_name, int column_num
 , COLUMN column[], int * test_flag, int * create_flag)
 {
     int ret = 0;
     char * errmsg = NULL;
     char sql[200];
     char * pSql;
     char new_val[20];
     char  new_id[3];
     int i;
     char test_val[100];


     pSql = sql;
     strcpy(pSql, "update ");
     strcat(pSql, pTable_name);
     strcat(pSql, " set ");

     if((*test_flag == 0) && (*create_flag))
     {
         strcat(pSql, "name = ");
         printf("please input a new name:/n");
         scanf("%s",test_val);
         strcat(pSql,"/'");
         strcat(pSql,test_val);
         strcat(pSql, "/', sex = ");
         printf("please input a new sex: /n");
         scanf("%s", test_val);
         strcat(pSql, "/'");
         strcat(pSql, test_val);
         strcat(pSql, "/', age = ");
         printf("please input a new age:/n");
         scanf("%s",test_val);
         strcat(pSql,test_val);
         strcat(pSql, " where id = ");
         printf("please input a id that you want to change:/n");
         scanf("%s",test_val);
         strcat(pSql, test_val);
         strcat(pSql, ";");
     }
     if(*create_flag == 0)
     {
         for(i = 1; i < column_num-1; i++)
         {
             strcat(pSql, column[i].column_name);
             strcat(pSql, " = ");
             if(strcmp(column[i].column_type, "text") ==0)
             {
                 strcat(pSql, "/'");
                 memset(new_val, 0, sizeof(new_val));
                 printf("please input a new %s/n", column[i].column_name);
                 scanf("%s",new_val);
                 strcat(pSql, new_val);
                 strcat(pSql, "/'");
                 strcat(pSql, " , ");
             }
             else
             {
                 memset(new_val, 0, sizeof(new_val));
                 printf("please input a new %s/n", column[i].column_name);
                 scanf("%s",new_val);
                 strcat(pSql, new_val);
                 strcat(pSql, " , ");
             }
         }

         strcat(pSql, column[i].column_name);
         strcat(pSql, " = ");

         if(strcmp(column[column_num-1].column_type, "text") ==0)
         {
             strcat(pSql, "/'");
             memset(new_val, 0, sizeof(new_val));
             printf("please input a new %s/n", column[i].column_name);
             scanf("%s",new_val);
             strcat(pSql, new_val);
             strcat(pSql, "/'");
             strcat(pSql, " ");
         }
         else
         {
             memset(new_val, 0, sizeof(new_val));
             printf("please input a new %s/n", column[i].column_name);
             scanf("%s",new_val);
             strcat(pSql, new_val);
             strcat(pSql, " ");
         }

         strcat(pSql, "where id = ");
         printf("please input the id that you want to change its value:/n");
         scanf("%s",new_id);
         strcat(pSql, new_id);
         strcat(pSql, ";");
     }
     printf("sqlite > %s/n/n",pSql);

     ret = sqlite3_exec(db, pSql, NULL, NULL, &errmsg);
     if(ret != SQLITE_OK)
     {
         printf("error:%d:%s/n", ret, errmsg);
         exit(1);
     }

     return;

 }

 void db_delete(sqlite3 * db, char * pTable_name)
 {
     int ret = 0;
     char * errmsg = NULL;
     char sql[200];
     char * pSql;
     char tmp_name[20];
     char tmp_id[3];


     pSql = sql;
     strcpy(pSql, "delete from ");
     strcat(pSql, pTable_name);
     strcat(pSql, " where id = ");
     printf("please input a id that you want to delete:/n");
     scanf("%s",tmp_id);
     strcat(pSql, tmp_id);
     strcat(pSql, ";");

     printf("/nsqlite > %s/n/n",pSql);

     ret = sqlite3_exec(db, pSql, NULL, NULL, &errmsg);
     if(ret != SQLITE_OK)
     {
         printf("error:%d:%s/n", ret, errmsg);
         exit(1);
     }

     return;
 }

 void db_empty(sqlite3 * db, char * pTable_name)
 {
     int ret = 0;
     char * errmsg = NULL;
     char sql[200];
     char * pSql;


     pSql = sql;
     strcpy(pSql, "delete from ");
     strcat(pSql, pTable_name);
     strcat(pSql,";");

     printf("/nsqlite > %s/n/n",pSql);

     ret = sqlite3_exec(db, pSql, NULL, NULL, &errmsg);
     if(ret != SQLITE_OK)
     {
         printf("error:%d:%s/n", ret, errmsg);
         exit(1);
     }

     return;
 }

 void db_drop(sqlite3 * db, char * pTable_name, int * test_flag
 , int * create_flag)
 {
     int ret = 0;
     char * errmsg = NULL;
     char sql[200];
     char * pSql;


     pSql = sql;
     strcpy(pSql, "drop table ");
     strcat(pSql, pTable_name);
     strcat(pSql,";");

     if(*test_flag)
     {
         printf("/nsqlite > %s/n/n",pSql);
     }

     if(*create_flag == 0)
     {
         printf("/nsqlite > %s/n/n",pSql);
     }

     ret = sqlite3_exec(db, pSql, NULL, NULL, &errmsg);
     if(ret != SQLITE_OK)
     {
         printf("error:%d:%s/n", ret, errmsg);
         exit(1);
     }

     return;
 }