C#でCSVファイルからデータを読み取ってデータベースに保存する方法

using IronXL;
using System.Data;

public class CSVReader
{
    // Reads a CSV file and converts it to a DataTable
    public DataTable ReadCSV(string filePath)
    {
        WorkBook workbook = WorkBook.Load(filePath);
        WorkSheet sheet = workbook.DefaultWorkSheet;
        // Convert to DataTable for easier processing
        DataTable dataTable = sheet.ToDataTable(true); // Set to 'true' if your CSV has a header row
        return dataTable;
    }
}

Imports IronXL
Imports System.Data

Public Class CSVReader
	' Reads a CSV file and converts it to a DataTable
	Public Function ReadCSV(ByVal filePath As String) As DataTable
		Dim workbook As WorkBook = WorkBook.Load(filePath)
		Dim sheet As WorkSheet = workbook.DefaultWorkSheet
		' Convert to DataTable for easier processing
		Dim dataTable As DataTable = sheet.ToDataTable(True) ' Set to 'true' if your CSV has a header row
		Return dataTable
	End Function
End Class

using System.Data.SqlClient; // For .NET Core/.NET 5+, use Microsoft.Data.SqlClient instead

public class DatabaseConnector
{
    // Connection string to connect to the database
    private string connectionString = "your_connection_string_here";

    public SqlConnection ConnectToDatabase()
    {
        SqlConnection connection = new SqlConnection(connectionString);
        connection.Open();
        return connection;
    }
}

Imports System.Data.SqlClient ' For .NET Core/.NET 5+, use Microsoft.Data.SqlClient instead

Public Class DatabaseConnector
    ' Connection string to connect to the database
    Private connectionString As String = "your_connection_string_here"

    Public Function ConnectToDatabase() As SqlConnection
        Dim connection As New SqlConnection(connectionString)
        connection.Open()
        Return connection
    End Function
End Class

using System;
using System.Data;
using System.Data.SqlClient; // For .NET Core/.NET 5+, use Microsoft.Data.SqlClient instead

public class DataImporter
{
    public void ImportData(DataTable dataTable)
    {
        using (SqlConnection connection = new DatabaseConnector().ConnectToDatabase())
        {
            // Check if the table exists and create it if it does not.
            string tableName = "CSVData"; // Use a valid SQL table name format
            string checkTable = $"IF NOT EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = '{tableName}') BEGIN ";
            string createTable = "CREATE TABLE " + tableName + " (";
            for (int i = 0; i < dataTable.Columns.Count; i++)
            {
                createTable += $"[{dataTable.Columns[i].ColumnName}] NVARCHAR(MAX)";
                if (i < dataTable.Columns.Count - 1)
                    createTable += ", ";
            }
            createTable += ") END";
            SqlCommand createTableCommand = new SqlCommand(checkTable + createTable, connection);
            createTableCommand.ExecuteNonQuery();

            // Now we use SqlBulkCopy to import the data
            using (SqlBulkCopy bulkCopy = new SqlBulkCopy(connection))
            {
                bulkCopy.DestinationTableName = tableName;
                try
                {
                    bulkCopy.WriteToServer(dataTable);
                    Console.WriteLine("Data imported successfully!");
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
            }
        }
    }
}

Imports System
Imports System.Data
Imports System.Data.SqlClient ' For .NET Core/.NET 5+, use Microsoft.Data.SqlClient instead

Public Class DataImporter
    Public Sub ImportData(dataTable As DataTable)
        Using connection As SqlConnection = New DatabaseConnector().ConnectToDatabase()
            ' Check if the table exists and create it if it does not.
            Dim tableName As String = "CSVData" ' Use a valid SQL table name format
            Dim checkTable As String = $"IF NOT EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = '{tableName}') BEGIN "
            Dim createTable As String = "CREATE TABLE " & tableName & " ("
            For i As Integer = 0 To dataTable.Columns.Count - 1
                createTable &= $"[{dataTable.Columns(i).ColumnName}] NVARCHAR(MAX)"
                If i < dataTable.Columns.Count - 1 Then
                    createTable &= ", "
                End If
            Next
            createTable &= ") END"
            Dim createTableCommand As New SqlCommand(checkTable & createTable, connection)
            createTableCommand.ExecuteNonQuery()

            ' Now we use SqlBulkCopy to import the data
            Using bulkCopy As New SqlBulkCopy(connection)
                bulkCopy.DestinationTableName = tableName
                Try
                    bulkCopy.WriteToServer(dataTable)
                    Console.WriteLine("Data imported successfully!")
                Catch ex As Exception
                    Console.WriteLine(ex.Message)
                End Try
            End Using
        End Using
    End Sub
End Class

class Program
{
    static void Main(string[] args)
    {
        string filePath = "path_to_your_csv_file.csv";
        CSVReader reader = new CSVReader();
        DataTable dataTable = reader.ReadCSV(filePath);
        DataImporter importer = new DataImporter();
        importer.ImportData(dataTable);
        Console.WriteLine("Data imported successfully!");
    }
}

Friend Class Program
	Shared Sub Main(ByVal args() As String)
		Dim filePath As String = "path_to_your_csv_file.csv"
		Dim reader As New CSVReader()
		Dim dataTable As DataTable = reader.ReadCSV(filePath)
		Dim importer As New DataImporter()
		importer.ImportData(dataTable)
		Console.WriteLine("Data imported successfully!")
	End Sub
End Class