用c语言动态操作sqilite3数据库v2.0

/* 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;

}