.net core利用MySqlBulkLoader大数据批量导入MySQL

最近用core写了一个数据迁移小工具，从SQLServer读取数据，加工后导入MySQL，由于数据量太过庞大，数据表都过百万，常用的dapper已经无法满足。三大数据库都有自己的大数据批量导入数据的方式，

MSSQL有SqlBulkCopy，MYSQL有MySqlBulkLoader，Oracle有OracleBulkCopy，对应各自的驱动。

一：生成csv文件

public static class CSVEx
    {
        /// <summary>
        ///将DataTable转换为标准的CSV
        /// </summary>
        /// <param name="table">数据表</param>
        /// <returns>返回标准的CSV</returns>
        public static void ToCsv(this DataTable table)
        {
            //以半角逗号（即,）作分隔符，列为空也要表达其存在。
            //列内容如存在半角逗号（即,）则用半角引号（即""）将该字段值包含起来。
            //列内容如存在半角引号（即"）则应替换成半角双引号（""）转义，并用半角引号（即""）将该字段值包含起来。
            StringBuilder sb = new StringBuilder();
            DataColumn colum;
            foreach (DataRow row in table.Rows)
            {
                for (int i = 0; i < table.Columns.Count; i++)
                {
                    colum = table.Columns[i];
                    if (i != 0) sb.Append(",");
                    if (colum.DataType == typeof(string) && row[colum].ToString().Contains(","))
                    {
                        sb.Append("\"" + row[colum].ToString().Replace("\"", "\"\"") + "\"");
                    }
                    else sb.Append(row[colum].ToString());
                }
                sb.AppendLine();
            }
 
            File.WriteAllText(table.TableName + ".csv", sb.ToString());
        }
 
    }

　二：批量导入数据

public static class MySqlHelper
    {
        /// <summary>
        /// 批量导入
        /// </summary>
        /// <param name="_mySqlConnection"></param>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static int BulkLoad(MySqlConnection _mySqlConnection, DataTable table)
        {
            var columns = table.Columns.Cast<DataColumn>().Select(colum => colum.ColumnName).ToList();
            MySqlBulkLoader bulk = new MySqlBulkLoader(_mySqlConnection)
            {
                FieldTerminator = ",",
                FieldQuotationCharacter = '"',
                EscapeCharacter = '"',
                LineTerminator = "\r\n",
                FileName = table.TableName + ".csv",
                NumberOfLinesToSkip = 0,
                TableName = table.TableName,
 
            };
 
            bulk.Columns.AddRange(columns);
            return bulk.Load();
        }
    }