用C# 编写一个导出mysql 数据库文档的完整代码

以下是一个使用C#编写的导出MySQL数据库文档的示例代码：

using System;
using System.IO;
using MySql.Data.MySqlClient;

namespace ExportMySQLDoc
{
    class Program
    {
        static void Main(string[] args)
        {
            string connectionString = "Server=your_server;Database=your_database;Uid=your_username;Pwd=your_password;";
            string outputFilePath = "database_doc.txt";
            
            try
            {
                using (MySqlConnection connection = new MySqlConnection(connectionString))
                {
                    connection.Open();

                    string sql = "SELECT TABLE_NAME, COLUMN_NAME, DATA_TYPE, COLUMN_TYPE, IS_NULLABLE, COLUMN_KEY, COLUMN_DEFAULT, EXTRA, COLUMN_COMMENT " +
                                 "FROM INFORMATION_SCHEMA.COLUMNS " +
                                 "WHERE TABLE_SCHEMA = DATABASE();";

                    MySqlCommand command = new MySqlCommand(sql, connection);
                    MySqlDataReader reader = command.ExecuteReader();

                    using (StreamWriter writer = new StreamWriter(outputFilePath))
                    {
                        writer.WriteLine("Table Name | Column Name | Data Type | Column Type | Is Nullable | Column Key | Column Default | Extra | Column Comment");
                        writer.WriteLine("-----------|-------------|-----------|-------------|--------------|------------|----------------|-------|----------------");

                        while (reader.Read())
                        {
                            writer.WriteLine($"{reader["TABLE_NAME"]} | {reader["COLUMN_NAME"]} | {reader["DATA_TYPE"]} | {reader["COLUMN_TYPE"]} | {reader["IS_NULLABLE"]} | {reader["COLUMN_KEY"]} | {reader["COLUMN_DEFAULT"]} | {reader["EXTRA"]} | {reader["COLUMN_COMMENT"]}");
                        }
                    }

                    reader.Close();
                }

                Console.WriteLine("Database documentation exported successfully.");
            }
            catch (Exception ex)
            {
                Console.WriteLine($"An error occurred: {ex.Message}");
            }

            Console.ReadLine();
        }
    }
}

请注意，你需要替换your_server，your_database，your_username和your_password为你自己的MySQL服务器信息。

此代码将查询MySQL数据库的INFORMATION_SCHEMA.COLUMNS视图，并将结果导出到名为database_doc.txt的文件中。导出的文档将包含表名、列名、数据类型、列类型、是否可为空、列主键、列默认值、额外信息和列注释