Question

我有一些旧的SQL代码在从数据库查询时使用左连接。我不知道如何使用EF做到这一点，但我可以想象它更简单。（VB.NET最新版本）

这是SQL代码：

'Now Change each of the dimension values on the EDD stack to EDD dimension Values
' - if Not deleted And on the stack

SqlString = "SELECT * FROM StackUp " +
            "LEFT JOIN StackUpItems On IdStackUp=StackUpID " +
            "LEFT JOIN DimensionValues ON DimensionValuesId=IdDimensionvalues " +
            "WHERE IdStackUp=" + StackUpId.ToString + " AND " +
            "isnull(IsDimensionValuesDeleted,0)=0 AND isnull(StackUpItems.IsDeleted,0)=0  ;"
SqlDataAdapter = New SqlDataAdapter(SqlString, SqlConnectionString)
TableNow = New DataTable
SqlDataAdapter.Fill(TableNow)

我尝试过一些东西，但是当我谈到这些类型的查询时，我不知道我在做什么。

以下是我的数据库对象的代码：

Function ToggleIsEDD(ByVal StackUpId) As Boolean

  'main try
  Try
      Dim IdNow As Integer = StackUpId
      Dim StackUpNow As IEnumerable(Of Stackup) = (From a In Db.Stackup Where a.IdStackup = IdNow).ToList

Answer 1

以下是我的工作：

''Now Change each of the dimension values on the EDD stack to EDD dimension Values
        '' - if Not deleted And on the stack
        '================================================================
        'This might need "or not null" statements within query as well
        '================================================================
        StackUpNow = (From a In Db.StackupItems
                      Where a.IdStackupItem =
                          IdNow And Not a.Stackup.IsDeleted And Not a.DimensionValues.IsDimensionValuesDeleted
                          ).ToList

左边加入实体框架6

1 个答案: