我正在使用hibernate＆gt; 5.2.10.Final，并使用FETCH JOIN来急切加载内部实体。
@OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
@JoinTable(name = "XYX", joinColumns = @JoinColumn(name = "TT"), inverseJoinColumns = @JoinColumn(name = "TT"))
@Fetch(FetchMode.JOIN)
private Set<PWR> pwrs;
由于FetchType设置为Lazy，而FetchMode设置为JOIN，因此在相关查询中，pwrs会急切地加载。
所以，我的问题是，如果我们使用FetchMode作为JOIN，我们不会使用FetchType吗？
答案 0 :(得分：0)
public class MainViewModel: INotifyPropertyChanged
{
Random _rnd = new Random();
private MyGridData _selectedData;
private ObservableCollection<MyGridData> _gridData;
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
public MainViewModel()
{
var newData = new List<MyGridData>
{
new MyGridData { Column1 = "AAAAAA 01", Column2 = "aaaaaaaa 02" },
new MyGridData { Column1 = "BBBBBB 01", Column2 = "bbbbbbbb 02" },
new MyGridData { Column1 = "CCCCCC 01", Column2 = "cccccccc 02" },
};
GridData = new ObservableCollection<MyGridData>(newData);
}
public MyGridData SelectedData
{
get { return _selectedData; }
set
{
if (value == _selectedData) //if same item selected
return;
_selectedData = value;
OnPropertyChanged();
DoSomethingWhenValueChanged(); // Will add a new line
}
}
public ObservableCollection<MyGridData> GridData
{
get { return _gridData; }
set
{
if (value == _gridData)
return;
_gridData = value;
OnPropertyChanged();
}
}
private void DoSomethingWhenValueChanged()
{
var newData = GridData.ToList();
newData.Add(new MyGridData { Column1 = (_rnd.Next(100)).ToString(), Column2 = (_rnd.Next(1000)).ToString() }); //Add new random item
GridData = new ObservableCollection<MyGridData>(newData); //update your DataGrid
}
}
public class MyGridData
{
public string Column1 { get; set; }
public string Column2 { get; set; }
}
会覆盖@Fetch(FetchMode.JOIN)您无法同时使用这两者。