Question

（我应该说这对于vb.net来说还是比较新的）

我在覆盖数据库中的条目时遇到问题。我认为问题是SqlDataAdapter.Update没有使用我创建的新数据表信息正确覆盖数据库。

据我了解，当我告诉它更新时，它应该完全用数据表替换数据库中的信息......不是吗？

简而言之，这就是问题所在：

基本上，我有一个数据库（.mdf文件），其中有一个名为'test'的表。我使用SqlDataAdapter使用'test'制作数据集。我有一个我在csv中解析的数据表 - 它被称为'ToLoad'。我现在要清除'test'数据表，复制csv数据表中的所有条目，然后将其保存到数据库中。

我已经调试了所有这一切似乎工作正常，除非我使用SqlDataAdapter.Update我得到一个错误告诉我我不能复制主键。这是因为在从数据表中输入新条目之前，不会完全从数据库中清除旧条目。

我已经检查过测试数据表在代码的早期实际被清除了......它确实如此。我已经检查过新的csv条目被复制到'test'数据表......并且它们是。

您可以提供的任何帮助真的赞赏

由于克雷格

'MAKE A NEW SQL CONNECTION
Dim DBConnection As New SqlConnection

'SET THE CONNECTION STRING.
DBConnection.ConnectionString = "Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Project\Members.mdf;Integrated Security=True"

'OPEN THE CONNECTION TO THE DATABASE
DBConnection.Open()

'OPEN AN ADAPTER AND SELECT EVERYTHING FROM THE 'TEST' TABLE
Dim mySqlDataAdapter As New SqlDataAdapter("SELECT * FROM Test", DBConnection)
Dim mySqlCommandBuilder As New SqlCommandBuilder(mySqlDataAdapter)





Dim DBDataset As DataSet = New DataSet

'FILL THE DATASET WITH THE TEST TABLE  
 mySqlDataAdapter.Fill(DBDataset, "Test")

'CLEAR ALL ENTRIES IN THE DATATABLE (SO I CAN FILL IT FROM SCRATCH)
 DBDataset.Tables("test").Clear()





 ''SET UP A LOOP TO ADD EACH RECORD FROM THE CSV DATATABLE TO THE DATABASE DATATABLE

  Dim CSV_row_number As Int16
  CSV_row_number = ds.Tables("toload").Rows.Count


  Dim i As Int16   
  i = 0
       Do Until i = CSV_row_number - 1


            'MAKES TWO NEW DATAROW OBJECTS
            Dim DB_row As DataRow
            Dim CSV_row As DataRow

            'SET THE CSV_ROW OBJECT EQUAL TO ROW(i) OF THE CSV DATATABLE
            CSV_row = ds.Tables("toload").Rows(i)

            DB_row = DBDataset.Tables("test").NewRow()

            'THIS SETS ALL OF THE COLUMNS IN THIS NEW ROW AS EQUAL TO ROW1 IN THE CSV DATATABLE
            DB_row("Name") = CSV_row("Name")
            DB_row("Quality") = CSV_row("Address")
            DBDataset.Tables("test").Rows.Add(DB_row)

            i = i + 1

        Loop



 mySqlDataAdapter.Update(DBDataset.Tables("Test"))

Answer 1

经过一段时间的谷歌搜索和一些反复试验后，我自己解决了这个问题。发布我的代码，以防其他人使用

克雷格

 'MAKE A NEW SQL CONNECTION
    Dim DBConnection As New SqlConnection

    'SET THE CONNECTION STRING. YOU GET THIS BY GOING TO SERVER EXPLORER, THEN CLICKING ON THE DATABASE
    'THE CONNECTION STRING IS IN PROPERTIES 
    DBConnection.ConnectionString = "Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Users\ME\Project\Members.mdf;Integrated Security=True"

    'OPEN THE CONNECTION TO THE DATABASE
    DBConnection.Open()



    'THIS OPENS AN ADAPTER TO THE DATABASE, AND SELECTS EVERYTHING FROM THE 'TEST' TABLE IN THAT DATABASE
    Dim mySqlDataAdapter As New SqlDataAdapter("SELECT * FROM MemberList", DBConnection)
    'THIS LETS US USE SQL ON THE DATATABLE (IT GETS PASSED THE ABOVE SQL STATEMENT)
    Dim mySqlCommandBuilder As New SqlCommandBuilder(mySqlDataAdapter)


    'THIS MAKES ANOTHER NEW DATASET 
    Dim DBDataset As DataSet = New DataSet


    ''THIS FILLS THAT DATASET WITH THE TEST TABLE (WHICH THE DATA ADAPTOR GRABBED ABOVE) 
    mySqlDataAdapter.FillSchema(DBDataset, SchemaType.Source, "MemberList")
    mySqlDataAdapter.Fill(DBDataset, "MemberList")


    'THIS MAKES A NEW DATATABLE 
    'I THEN MAKE ALL CHANGES NEEDED 

    Dim EDITmembers As DataTable
    EDITmembers = DBDataset.Tables("MemberList")


    ''FIRST, IM GOING TO CLEAR ALL ENTRIES IN THE DATATABLE (SO I CAN FILL IT FROM SCRATCH)

    'COUNT THE NUMBER OF ENTRIES TO CLEAR
    Dim RowsInDB As Integer
    RowsInDB = EDITmembers.Rows.Count()

    'SET UP A LOOP TO CLEAR THEM
    Dim Data_row As DataRow
    Dim k As Integer = 0

    Do Until k = RowsInDB

        Data_row = EDITmembers.Rows(k)

        Data_row.Delete()

        k = k + 1

    Loop

    'ONCE ALL THE ROWS ARE CLEARED, SAVE THE CHANGES BY UPDATING THE ACTUAL DATABASE
    mySqlDataAdapter.Update(DBDataset, "MemberList")





    ''THEN I SET UP A LOOP TO ADD EACH RECORD FROM THE CSV DATATABLE TO THE DATABASE DATATABLE
    ''I FIRST NEED TO KNOW HOW MANY ITERATIONS OF THE LOOP TO DO

    Dim CSV_row_number As Int16
    'COUNT THE NUMBER OF ROWS AND SET THE ABOVE INT EQUAL TO THIS
    CSV_row_number = ToLoad.Rows.Count


    Dim j As Int16   
    j = 0
    Do Until j = CSV_row_number - 1


        'THIS MAKES TWO NEW DATAROW OBJECTS
        Dim DB_row As DataRow
        Dim CSV_row As DataRow

        'THIS SETS THE CSV_ROW OBJECT EQUAL TO THE FIRST ROW OF THE CSV DATATABLE
        CSV_row = ToLoad.Rows(j)


        'THIS SETS DB_ROW EQUAL TO A NEW ROW IN THE DATATABLE MADE FROM THE DATABASE
        DB_row = EDITmembers.NewRow()

        'THIS SETS ALL OF THE COLUMNS IN THIS NEW ROW AS EQUAL TO THE CORRESPONDING ROW IN THE CSV DATATABLE
        DB_row("Contact Name") = CSV_row("Contact Name")
        DB_row("Do not mail") = CSV_row("Do not mail")
        DB_row("Membership Type") = CSV_row("Membership Type")
        DB_row("Street Address") = CSV_row("Street Address")
        DB_row("Supplemental Address 1") = CSV_row("Supplemental Address 1")
        DB_row("Supplemental Address 2") = CSV_row("Supplemental Address 2")
        DB_row("City") = CSV_row("City")
        DB_row("Postal Code") = CSV_row("Postal Code")
        DB_row("Email") = CSV_row("Email")
        DB_row("Phone (primary)") = CSV_row("Phone (primary)")


        EDITmembers.Rows.Add(DB_row)

        j = j + 1

    Loop




   'UPDATE THE DATABASE WITH ALL THE CHANGES
    mySqlDataAdapter.Update(DBDataset, "MemberList")
    MessageBox.Show("done!")

SqlDataAdapter.Update没有更新

1 个答案: