vb.net - How do I query SQL data then insert or update depending on the result

Question

I am a beginner at this. But let me explain what I need to do and show you my code

1. I have a CSV file. inside the CSV I have a projectnumber, city,state,country
2. I have a SQL table with the same column
3. I want to use vb.net to check if projectnumber exists in sql table if exists then I want to run update statement. if it does not exists then I want to run insert statement.

I have the program working . but I am just wondering if this would be the correct way or my code is some hack way of doing it.

LEGEND: DTTable is data table with CSV inside

DT is data table with SQL result data

1. First I fill insert all lines in the CSV into a data table

       Dim parser As New FileIO.TextFieldParser(sRemoteAccessFolder & "text.csv")
       parser.Delimiters = New String() {","}
       parser.ReadLine()
       Do Until parser.EndOfData = True
           DTTable.Rows.Add(parser.ReadFields())
       Loop
       parser.Close()
   

2. then I use oledbdataadapter to run the select query and fill another data table with the result of the select statement

               SQLString = "select * from tblProjects where ProjectID='" & DTTable.Rows.Item(i).Item("ProjectNumber") & "'"
               da = New OleDb.OleDbDataAdapter(SQLString, Conn)
               da.Fill(dt)
   

3. then I run if statement

   If dt.Rows.Count = 0 then
       SQLString = "INSERT STATEMENT HERE"
       oCmd = New OleDb.OleDbCommand(SQLString, Conn)
       oCmd.ExecuteNonQuery()
   

   Else SQLString = "UPDATE STATEMENT HERE" oCmd = New OleDb.OleDbCommand(SQLString, Conn) oCmd.ExecuteNonQuery() End if

4. ALL above code is run inside a for loop, to go through all the lines in the CSV

   For i = 0 To DTTable.Rows.Count - 1

what do you think? please advise

thank you

Answer 1

就个人而言，我不会使用 .NET。我会将表导入到临时 SQL Server 表中，然后编写查询以将临时表中的数据插入/更新到常规表中。如果数据集很大，这肯定是您想要的方式。

如果这是您需要经常重复的过程，您可以制作一个 SSIS 包。

Answer 2

我会使用datareader = command.ExecuteReader(). 然后：

If datareader.Read() then
  'Update query using datareader(0) as a where predicate goes here
ElseIf datareader(0) = Nothing then
  'Insert query goes here
End If

我应该说，我也是一个相对新手，所以也许其他人可以提出一种更优雅的方法。