最近用core寫了一個數據遷移小工具,從SQLServer讀取數據,加工后導入MySQL,由於數據量太過龐大,數據表都過百萬,常用的dapper已經無法滿足。三大數據庫都有自己的大數據批量導入數據的方式,
MSSQL有SqlBulkCopy,MYSQL有MySqlBulkLoader,Oracle有OracleBulkCopy,對應各自的驅動。
一:生成csv文件
public static class CSVEx
{
/// <summary>
///將DataTable轉換為標准的CSV
/// </summary>
/// <param name="table">數據表</param>
/// <returns>返回標准的CSV</returns>
public static void ToCsv(this DataTable table)
{
//以半角逗號(即,)作分隔符,列為空也要表達其存在。
//列內容如存在半角逗號(即,)則用半角引號(即"")將該字段值包含起來。
//列內容如存在半角引號(即")則應替換成半角雙引號("")轉義,並用半角引號(即"")將該字段值包含起來。
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:批量導入數據
public static class MySqlHelper
{
/// <summary>
/// 批量導入
/// </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();
}
}
demo地址:https://github.com/xiaopotian1990/MySqlBulkLoaderDemo
