来自SQLI的C++奇怪文本

Question

我想创建一个构造函数来填充sqlite数据库中的数据。 当我运行创建对象的for循环并填充我的表格时，一切似乎都正常工作接受一些奇怪的输出。我认为这可能与内存指针有关，但我对C++很陌生，我不确定我做错了什么。

库存构造

Inventory::Inventory(int id) 
{ 
CC_Number cn; 
char result[100]; // array to hold the result. 
strcpy(result,"SELECT * FROM Inventory Where Inventory_ID = "); 
strcat(result,cn.int_to_char(id)); 
strcat(result,";"); 
db = new CC_Database("CC_Prepper_Inventory.sqlite"); 

vector<vector<string> > r = db->query(result); 
db->close(); 
for(vector<vector<string> >::iterator it = r.begin(); it < r.end(); ++it) 
{ 
    vector<string> row = *it; 
    CC_String cs; 
     setInv_ID(atoi(cs.toConChar(row.at(0)))); 
     Item item(atoi(cs.toConChar(row.at(1)))); 
     setItem(item); 
     setQnty(atof(cs.toConChar(row.at(2)))); 
     Location loc(atoi(cs.toConChar(row.at(3)))); 
     setLoc(loc); 
} 

} 

项目构造

Item::Item(int id) 
{ 
CC_Number cn; 
char result[100]; // array to hold the result. 
strcpy(result,"SELECT * FROM Item Where Item_ID = "); 
strcat(result,cn.int_to_char(id)); 
strcat(result,";"); 
db = new CC_Database("CC_Prepper_Inventory.sqlite"); 

vector<vector<string> > r = db->query(result); 
db->close(); 
for(vector<vector<string> >::iterator it = r.begin(); it < r.end(); ++it) 
{ 
    vector<string> row = *it; 
    CC_String cs; 
     setItem_ID(atoi(cs.toConChar(row.at(0)))); 

     setCat_ID(atoi(cs.toConChar(row.at(1)))); 
     setItem_Name(cs.toConChar(row.at(2))); 
} 

} 

位置构造

Location::Location(int id) 
{ 
CC_Number cn; 
char result[100]; // array to hold the result. 
strcpy(result,"SELECT Loc_ID, Loc_Name FROM Location Where Loc_ID = "); 
strcat(result,cn.int_to_char(id)); 
strcat(result,";"); 
db = new CC_Database("CC_Prepper_Inventory.sqlite"); 

vector<vector<string> > r = db->query(result); 
db->close(); 
for(vector<vector<string> >::iterator it = r.begin(); it < r.end(); ++it) 
{ 
    vector<string> row = *it; 
    CC_String cs; 
     setLoc_ID(id); 
     setLoc_Name(cs.toConChar(row.at(1))); 
} 
} 

类构造函数

Category::Category(int id) 
{ 
CC_Number cn; 
char result[100]; // array to hold the result. 
strcpy(result,"SELECT * FROM Category Where Cat_ID = "); 
strcat(result,cn.int_to_char(id)); 
strcat(result,";"); 
db = new CC_Database("CC_Prepper_Inventory.sqlite"); 

vector<vector<string> > r = db->query(result); 
db->close(); 
for(vector<vector<string> >::iterator it = r.begin(); it < r.end(); ++it) 
{ 
    vector<string> row = *it; 
    CC_String cs; 
     setCat_ID(id); 
     setCat_Name(cs.toConChar(row.at(1))); 
} 
} 

For循环用于调用构造函数

void MainWindow::fillTable() 
{ 
ui->mainTable->clear(); 
db = new CC_Database("CC_Prepper_Inventory.sqlite"); 
vector<vector<string> > result = db->query("SELECT Inventory_ID FROM Inventory;"); 
db->close(); 
ui->mainTable->setRowCount(result.size()); 
int j = 0; 
for(vector<vector<string> >::iterator it = result.begin(); it < result.end(); ++it) 
{ 
    vector<string> row = *it; 
    Inventory i(atoi(cs.toConChar(row.at(0)))); 

    cout << i.getItem().getItem_Name() << endl; 
    cout << i.getItem().getCategory().getCatName() << endl; 
    cout << cn.dbl_to_char(i.getQnty()) << endl; 
    cout << i.getLoc().getLocName() << endl; 

    QTableWidgetItem *newItem1 = new QTableWidgetItem(QString::fromStdString(i.getItem().getItem_Name())); 
    QTableWidgetItem *newItem2 = new QTableWidgetItem(QString::fromStdString(i.getItem().getCategory().getCatName())); 
    QTableWidgetItem *newItem3 = new  QTableWidgetItem(QString::fromStdString(cn.dbl_to_char(i.getQnty()))); 
    QTableWidgetItem *newItem4 = new  QTableWidgetItem(QString::fromStdString(i.getLoc().getLocName())); 
    ui->mainTable->setItem(j,1,newItem1); 
    ui->mainTable->setItem(j,2,newItem2); 
    ui->mainTable->setItem(j,3,newItem3); 
    ui->mainTable->setItem(j,4,newItem4); 
    i.clear(); 
    j++; 
} 

QStringList qsl; 
qsl << "Item" << "Category" << "Quantity" << "Location"; 
ui->mainTable->setHorizontalHeaderLabels(qsl); 
} 

这里是输出，当我清点结果。

Food 
1 
B.O.L. 

Food 
3 
B.O.L. 

Food 
4 

0�an error 
Food 
3.14 
LE Item (
Item_ID INTEGER PRIMARY KEY AUTOINCREMENT, 
Cat_ID INTEGER NOT NULL, 
Item_Name TEXT NOT NULL)P++Ytablesqlite_sequencesqlite_sequenceCREATE TABLE sqlite_sequence(name,seq)� �� 

Food 
5  

我知道这是信息超载，但我不知道怎么解释我的问题。

Answer 1

我相信问题不在您发布的行中，但在其他地方。但是你的代码敦促一些修改：

1. 不使用字符数组来保存的SQL查询，使用的std :: string

2. 不要打开每一个查询到数据库的连接.. 。打开一次，执行多个查询