Question

代码必须用SQL Server的数据填充Array。然后将Array数据写入文件。现在它可以工作，但是可以优化我的“ For Next”。因为Counter可能确实很大，但这不是唯一要填充的数组

For i = 0 To Counter
Dim PR = (SQL.RunReader("SELECT Requirement FROM Programme_Requirements
JOIN Specialities ON Specialities.Id_Speciality=Programme_Requirements.Id_Speciality AND Specialities.SpecialityName='" & SpecialityName(i) &
"' JOIN Educational_Levels ON Educational_Levels.Id_EducationalLevel=Programme_Requirements.Id_EducationalLevel AND 
Educational_Levels.EducationalLevel ='" & DocumentTypeId(i) &
"' JOIN Forms_of_Study ON Forms_of_Study.Id_FormofStudy=Programme_Requirements.Id_FormofStudy AND 
Forms_of_Study.FormofStudyName ='" & EducationFormName(i) & "'", "Requirement"))
Next

Answer 1

不确定RunReader中发生了什么，请尝试此操作...

Private Sub ProcessArrays()
        Dim strSQL =
        "SELECT Requirement FROM Programme_Requirements
        JOIN Specialities ON Specialities.Id_Speciality=Programme_Requirements.Id_Speciality 
        JOIN Educational_Levels ON Educational_Levels.Id_EducationalLevel=Programme_Requirements.Id_EducationalLevel 
        JOIN Forms_of_Study ON Forms_of_Study.Id_FormofStudy=Programme_Requirements.Id_FormofStudy 
        WHERE  Specialities.SpecialityName= @SpecialtyName
        AND 
        Educational_Levels.EducationalLevel = @DocumentType
        AND 
        Forms_of_Study.FormofStudyName = @EducationFormName;"
        Using cn As New SqlConnection("Your connection string")
            Using cmd As New SqlCommand(strSQL, cn)
                cn.Open()
                For i As Integer = 0 To Counter
                    cmd.Parameters.Add("@SpecialtyName", SqlDbType.VarChar).Value = SpecialtyName(i)
                    cmd.Parameters.Add("@DocumentName", SqlDbType.VarChar).Value = DocumentTypeId(i)
                    cmd.Parameters.Add("@EducationFormName", SqlDbType.VarChar).Value = EducationFormName(i)
                    Using dr As SqlDataReader = cmd.ExecuteReader
                        'Use reader values
                    End Using
                Next
            End Using
        End Using
    End Sub

请我如何优化数据加载

1 个答案: