我创建了 "database.db",一切都很顺利,但为什么它不能在最后删除表格?每次运行时,我都会在创建表格时收到“表格已存在”的错误消息。
int main()
{
sqlite3 *db; //Database Handle
char *zErr;
int rc;
char *sql;
rc = sqlite3_open("database.db", &db);
if(rc)
{
cout << "Can't open database: " << sqlite3_errmsg(db) << endl;;
sqlite3_close(db);
exit(1);
}
sql = "create table test(PID int primary key, Name text)"; //sql query
rc = sqlite3_exec(db, sql, NULL, NULL, &zErr); //execute sql statement
if(rc != SQLITE_OK)
{
if (zErr != NULL)
{
cout << "SQL error: " << zErr << endl;
sqlite3_free(zErr);
}
}
else
{
sql = "insert into test values (1,'John')";
rc = sqlite3_exec(db, sql, NULL, NULL, &zErr);
sql = "insert into test values (2,'Smith')";
rc = sqlite3_exec(db, sql, NULL, NULL, &zErr);
}
//delete the table on exit.
rc = sqlite3_exec(db, "delete from test", NULL, NULL, &zErr);
sqlite3_close(db);
return 0;
}
此外,主键是否可以根据数据库中最后一个更大的键自动生成?