1
1.1【sqlite3_open】
1.1.1函数原型
【int sqlite3_open(const char *filename, /* Database filename (UTF-8) */sqlite3 **ppDb /* OUT: SQLite db handle */);】
1.1.2函数功能
打开数据库文件(创建一个数据库连接)
1.1.3函数参数
【filename】:数据库文件路径
【ppDb】:操作数据库指针存放空间的首地址
1.1.4返回值
【成功】:返回【SQLITE_OK】
【失败】:返回错误码
1.2【sqlite3_close】
1.2.1函数原型
【int sqlite3_close(sqlite3 *);】
1.2.2函数功能
关闭数据库连接
1.2.3函数参数
1.2.4返回值
1.3【sqlite3_exec】
1.3.1函数原型
【int sqlite3_exec(sqlite3*, /* An open database */
const char *sql, /* SQL to be evaluated */
int (*callback)(void*,int,char**,char**), /* Callback function */
void *, /* 1st argument to callback */
char **errmsg/* Error msg written here */);】
1.3.2函数功能
执行一条SQL语句
1.3.3函数参数
【sqlite3*】:数据库句柄
【sql】:要执行的SQL语句字符串首地址
【callback】:只有在select时才会使用,其余调用时传递【NULL】
【void*】:给回调函数的传参
【errmsg】:出错信息存放空间首地址(使用完毕后使用sqlite3_free释放空间)
1.3.4返回值
【成功】:返回【SQLITE_OK】
【失败】:返回错误码
源码示例(1):
c
typedef struct student
{
char name[32];
char sex[8];
int age;
}stu_t;
int main(void)
{
sqlite3 *pdb = NULL;
int ret = 0;
char cmdbuf[1024] = {0};
char *perrmsg = NULL;
stu_t s = {"张三", "男", 18};
ret = sqlite3_open("student.db", &pdb);
if (ret != SQLITE_OK)
{
fprintf(stderr, "sqlite3_open failed:%s\n", sqlite3_errmsg(pdb));
return -1;
}
sprintf(cmdbuf, "create table if not exists student (id integer primary key asc, name varchar(255), sex varchar(32), age integer);");
ret = sqlite3_exec(pdb, cmdbuf, NULL, NULL, &perrmsg);
if (ret != SQLITE_OK)
{
fprintf(stderr, "sqlite3_exec failed:%s\n", perrmsg);
sqlite3_free(perrmsg);
sqlite3_close(pdb);
return -1;
}
sprintf(cmdbuf, "insert into student values (NULL, '%s', '%s', %d);", s.name, s.sex, s.age);
ret = sqlite3_exec(pdb, cmdbuf, NULL, NULL, &perrmsg);
if (ret != SQLITE_OK)
{
fprintf(stderr, "sqlite3_exec failed:%s\n", perrmsg);
sqlite3_free(perrmsg);
sqlite3_close(pdb);
return -1;
}
sqlite3_close(pdb);
return 0;
}
源码示例(2):
c
/*练习:将一张单词表中单词及其含义插入到数据库中*/
int LoadDictToDB(void)
{
sqlite3 *pdb = NULL;
char cmdbuf[4096] = {0};
int ret = 0;
char *perrmsg = NULL;
FILE *fp = NULL;
char tmpbuff[4096] = {0};
char *pret = NULL;
char *ptmpword = NULL;
char *ptmpmean = NULL;
long len = 0;
long curlen = 0;
ret = sqlite3_open("dict.db", &pdb);
if (ret != SQLITE_OK)
{
fprintf(stderr, "fail to sqlite3_open:%s\n", sqlite3_errmsg(pdb));
return -1;
}
sprintf(cmdbuf, "create table if not exists dict (编号 integer primary key asc, 单词 varchar(64), 含义 varchar(4096));");
ret = sqlite3_exec(pdb, cmdbuf, NULL, NULL, &perrmsg);
if (ret != SQLITE_OK)
{
fprintf(stderr, "fail to sqlite3_exec:%s\n", perrmsg);
sqlite3_free(perrmsg);
sqlite3_close(pdb);
return -1;
}
fp = fopen("dict.txt", "r");
if (NULL == fp)
{
perror("fail to fopen");
return -1;
}
fseek(fp, 0, SEEK_END);
len = ftell(fp);
rewind(fp);
while (1)
{
pret = fgets(tmpbuff, sizeof(tmpbuff), fp);
if (NULL == pret)
{
break;
}
curlen = ftell(fp);
printf("已加载 %.2lf%%\r", (double)curlen / (double)len * 100);
fflush(stdout);
ptmpword = strtok(tmpbuff, " ");
ptmpmean = strtok(NULL, "\r");
sprintf(cmdbuf, "insert into dict values (NULL, \"%s\", \"%s\");", ptmpword, ptmpmean);
ret = sqlite3_exec(pdb, cmdbuf, NULL, NULL, &perrmsg);
if (ret != SQLITE_OK)
{
fprintf(stderr, "fail to sqlite3_exec:%s\n", perrmsg);
sqlite3_free(perrmsg);
sqlite3_close(pdb);
return -1;
}
}
sqlite3_close(pdb);
return 0;
}
int main(void)
{
if (access("dict.db", F_OK))
{
LoadDictToDB();
}
return 0;
}