我在我的项目中使用 FMDB，我在终端中构建了第一个 sqlite3 数据库，并将其加载到我的项目中。后来我对该数据库进行了一些更改，因此我将其从项目中删除（移动到垃圾箱），然后再次“添加文件”。但是运行结果似乎还是和以前的数据库一致，或者有时只是没有查询结果。我还尝试删除数据库并运行项目，它仍在运行且没有错误...此外，我导入了另一个名称的较新数据库，它也无法工作。那么我需要做些什么来完全删除objective-c中的数据库并重新加载一个吗？谢谢！
我的代码如下所示：
- (IBAction)submitButton:(id)sender {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:@"finalCarpool.db"];
FMDatabase* db = [FMDatabase databaseWithPath:writableDBPath];
NSLog(@"Is SQLite compiled with it's thread safe options turned on? %@!", [FMDatabase isSQLiteThreadSafe] ? @"Yes" : @"No");
if (![db open]) {
NSLog(@"Could not open db.");
}
FMResultSet *rs = [db executeQuery:@"select * from userinfo"];
int count=0;
while ([rs next]) {
count++;
NSLog(@"%i",count);
}
FMResultSet *rs2 = [db executeQuery:@"select id from userinfo where username = ? AND password= ?", usernameTextField.text,passwordTextField.text];
if ([rs2 next]) {
NSString *welcomeMessage=[[NSString alloc]initWithFormat:@"Welcome, %@",usernameTextField.text];
UIAlertView *myAlert = [[UIAlertView alloc]
initWithTitle:@"Successfully Login!"
message:welcomeMessage
delegate:nil
cancelButtonTitle:@"Okay"
otherButtonTitles:nil];
[myAlert show];
[self.loginDelegate backToLaunch];
}
else {
UIAlertView *myAlert = [[UIAlertView alloc]
initWithTitle:@"Something is wrong..."
message:@"Your username and/or password doesn't match!Please try again!"
delegate:nil
cancelButtonTitle:@"Okay"
otherButtonTitles:nil];
[myAlert show];
usernameTextField.text=Nil;
passwordTextField.text=Nil;
}
[usernameTextField resignFirstResponder];
[passwordTextField resignFirstResponder];
}