iPhone应用程序中的sqlite3

Question

我在sqlite3中建立3个表格。当我做下面的SELECT命令：

select us.saleSpecificProduct,us.fAtMall,u.name,u.gender,st.storeName 
    from UsersSale us,Users u,Stores st 
where u.userID=us.userID and st.storeID=us.saleStoreID order by us.saleID 

它工作正常的外壳，但如果我在我的iPhone应用程序把这个说法，我得到一个错误。

/* 
* read items from the database and store in itemw 
* 
*/ 
-(void)readItems { 

if (!database) return; // earlier problems 

// build select statement 
if (!selStmt) 
{ 
    const char *sql = "select us.saleSpecificProduct,us.fAtMall,u.name,u.gender,st.storeName from UsersSale us,Users u,Stores st where u.userID=us.userID and st.storeID=us.saleStoreID order by us.saleID"; 
     if (sqlite3_prepare_v2(database, sql, -1, &selStmt, NULL) != SQLITE_OK) 
    { 
     selStmt = nil; 
    } 

当我执行的应用程序，我在 “sqlite3_prepare_v2” }

有什么不对得到错误？

Answer 1

也许尝试把单引号里面

你的参数

因此，像：

WHERE u.userID = 'us.userID' AND st.storeID = 'us.saleStoreID' ORDER BY us.saleID 

你也应该尽量使用绑定获得安全声明：

例如

NSString *strGet = @" . . . WHERE u.userID = ? AND st.storeID = ? ORDER BY us.saleID" 

if(sqlite_prepare_v2(...) == SQLITE_OK) 
{ 
    sqlite3_bind_int(stmtGet, 1, us.userID); 
    sqlite3_bind_int(stmtGet, 2, us.saleStoreID); 

    while(sqlite3_step(stmtGet) == SQLITE_ROW) 
    { 
     DatabaseDataObject *myDataObj = [[DatabaseDataObject alloc] init]; 

     myDataObj.objID = sqlite3_column_int(0); 
     myDataObj.postcode = sqlite3_column_int(1); 

     // add to parameter array of objects 
     [myArr addObject:myDataObj]; 

     [myDataObj release]; 
    } 
}