创建具有相同列名和列数据类型的新版本数据表

Question

通过创建具有相同表的新 .accdb 并将表从 .mdbs 转换为 .accdbs，并且这些表具有相同的列名和相同的列数据类型。使用 OleDB 和 sql 来执行非查询。当我尝试从旧数据表列中为新列使用相同的数据类型时，我遇到了问题。我带来了填充 dTable

adp.Fill(dTable)

以下代码让我遇到了除 varchar 之外的不同数据类型的列。

Public Sub ConvertTable(dTable As DataTable, tableName As String)

    Dim i As Int16 = 0
    Dim j As Int16 = 0
    strConnOutput = SharedRoutines.GetAccessACEConnectionString(aceDatabase)
    Using con2 As New OleDbConnection(strConnOutput)
        con2.Open()
        Dim sqlText As String = ""

        'Set up query to create a table with the same name as the'
        'spreadsheet.'
        sqlText = "CREATE TABLE [" & tableName & "] ("

        'Create all the columns that exist in the spreadsheet.'
        For Each col As DataColumn In dTable.Columns
            sqlText &= "[" & col.ColumnName & "] varchar, "
        Next
        'Clean up the end of the CREATE query.'
        sqlText = sqlText.Substring(0, sqlText.Length - 2) & ")"

        Using cmValid As New OleDbCommand(sqlText, con2)
            cmValid.ExecuteNonQuery()
        End Using

        'Set the INSERT SQL query for the data in the spreadsheet.'
        sqlText = "INSERT INTO [" & tableName & "] ("
        'Add all the columns to the INSERT query.'
        For Each col As DataColumn In dTable.Columns
            sqlText &= "[" & col.ColumnName & "], "
        Next
        'Clean up the end of the query string and prepare for the parameters.'
        sqlText = sqlText.Substring(0, sqlText.Length - 2) & ") VALUES ("
        'Add all the parameter placeholders to the INSERT query.'
        For Each col As DataColumn In dTable.Columns
            sqlText &= "?, "
        Next
        'Clean up the end of the INSERT query.'
        sqlText = sqlText.Substring(0, sqlText.Length - 2) & ")"

        Try
            'Loop through all the rows of data in the spreadsheet.'
            For Each rw As DataRow In dTable.Rows
                Using cmValid As New OleDbCommand(sqlText, con2)

                    'Add a parameter for each column.'
                    For Each col As DataColumn In dTable.Columns
                        cmValid.Parameters.Add(New OleDbParameter(col.ColumnName, rw(col.ColumnName)))
                    Next
                    'Send data to the new table.'
                    cmValid.ExecuteNonQuery()

                End Using
            Next
        Catch ex As Exception
            j += 1
            convertResponse &= tableName & " from " & aceDatabase & " was not completed."
            MessageBox.Show(tableName & " from " & aceDatabase & " was not completed. Message:" & ex.ToString)
        End Try



        dTable.Dispose()
        i += 1

        convertResponse &= "Table " & tableName & " was added to " & aceDatabase & ControlChars.CrLf
    End Using

End Sub

我改变了 For Each 循环

        For Each col As DataColumn In dTable.Columns
            sqlText &= "[" & col.ColumnName & "] " & col.DataType.ToString & ", "
        Next

但现在 executeNonQuery() 正在引发语法错误。不是 col.dataType.Tostring 吗？ 带有 varchar 的 SqlText CREATE TABLE [BASIC_DESCRIPTION] ([ColumnName] varchar, [Order] varchar) 和....相比 CREATE TABLE [BASIC_DESCRIPTION] ([ColumnName] System.String, [Order] System.Int32) 我的问题是我需要在 sqlText 中添加什么以确保正在创建的新列与旧表的类型相同？我找到的最接近的答案是这个。 Link

Answer 1

我不是 VB.NET 人，但我会尝试放弃 .ToString 并希望它是隐式的，或者将其设为 .ToString() 因为它是一个方法调用。

Answer 2

从 here 创建了一个 GetDBType 函数并执行了 ToString。

      'Create all the columns that exist in the spreadsheet.'
        For Each col As DataColumn In dTable.Columns
            Dim colSQLType As SqlDbType = GetDBType(col.DataType)
            Dim colType As String = colSQLType.ToString

            sqlText &= "[" & col.ColumnName & "] " & colType & ", "
        Next