检索数据时数据库崩溃问题

This is the Database field values.

下面是我用来从 sqlite 数据库获取数据的代码

-(void)readDataFromRestaurantTable
{
    [self openDataBase];

    const char *dbpath = [databasePath UTF8String];

    if (sqlite3_open(dbpath, & database) == SQLITE_OK)
    {
        sqlite3_stmt  *statement = NULL;

        NSString *querySQL = [NSString stringWithFormat: @"SELECT * FROM RestaurantDB"];
        const char *query_stmt = [querySQL UTF8String];

        if (sqlite3_prepare_v2(database, query_stmt, -1, &statement, NULL) == SQLITE_OK) {

            while (sqlite3_step(statement) == SQLITE_ROW)
            {
                strRestaurantName = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 1)];
                strRestaurantAddress = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 2)];
                strRestaurantPhone = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 3)];
                strRestaurantLatitude = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 4)];
                strRestaurantLongitude = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 5)];

                NSLog(@"strRestaurantName :--> %@",strRestaurantName);
            }
        }
        sqlite3_finalize(statement);
    }
    sqlite3_close(database);
}

在前面的代码块中，应用程序不会进入

if (sqlite3_prepare_v2(database, query_stmt, -1, &statement, NULL) == SQLITE_OK)
{

}

这是得到语句 = 0x00000000我认为正是因为这个原因，它才不会进入 if 块。

崩溃时出错

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSPlaceholderString initWithUTF8String:]: NULL cString'
First throw call stack:
(0x18dc012 0x12a1e7e 0x18dbdeb 0xcbdce6 0x78e4 0x7bdf 0x2ca817 0x2ca882 0x2ebed9 0x2ebd14 0x2ea1ea 0x2ea06c 0x2ebc57 0x12b5705 0x1ec920 0x1ec8b8 0x40f0b4 0x12b5705 0x1ec920 0x1ec8b8 0x2ad671 0x2adbcf 0x2ad6a6 0x412bb9 0x12b5705 0x1ec920 0x1ec8b8 0x2ad671 0x2adbcf 0x2acd38 0x21c33f 0x21c552 0x1fa3aa 0x1ebcf8 0x1da5df9 0x185ff3f 0x185f96f 0x1882734 0x1881f44 0x1881e1b 0x1da47e3 0x1da4668 0x1e965c 0x2712 0x2645 0x1)
libc++abi.dylib: terminate called throwing an exception

请指导我实际问题出在哪里。

这是由于尝试使用 a 创建 NSString 对象引起的NULL细绳。它位于以下行之一：

[[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, ...)];

因此，在使用 sql 语句的结果创建 NSString 之前，您需要像这样检查 NULL：

char *tmp = sqlite3_column_text(statement, 1);
if (tmp == NULL)
    strRestaurantName = nil;
else
    strRestaurantName = [[NSString alloc] initWithUTF8String:tmp];