将几百万条数据导入到数据库中，怎么样高效率的导入？
下面我就介绍一个高效率的方法：
1、将数据库文件(DB.csv)导入到DataTable中：
/// <summary>
/// 将CSV文件的数据读取到DataTable中
/// </summary>
/// <param name="fileName">CSV文件路径</param>
/// <returns>返回读取了CSV数据的DataTable</returns>
public static DataTable OpenCSV(string filePath)
{
Encoding encoding = Encoding.GetEncoding("utf-8"); //Encoding.ASCII;//
DataTable dt = new DataTable();
FileStream fs = new FileStream(filePath, System.IO.FileMode.Open, System.IO.FileAccess.Read);
//StreamReader sr = new StreamReader(fs, Encoding.UTF8);
StreamReader sr = new StreamReader(fs, encoding);
//string fileContent = sr.ReadToEnd();
//encoding = sr.CurrentEncoding;
//记录每次读取的一行记录
string strLine = "";
//记录每行记录中的各字段内容
string[] aryLine = null;
string[] tableHead = null;
//标示列数
int columnCount = 0;
//标示是否是读取的第一行
bool IsFirst = true;
//逐行读取CSV中的数据
while ((strLine = sr.ReadLine()) != null)
{
//strLine = Common.ConvertStringUTF8(strLine, encoding);
//strLine = Common.ConvertStringUTF8(strLine);
if (IsFirst == true)
{
tableHead = strLine.Split(',');
IsFirst = false;
columnCount = tableHead.Length;
//创建列
for (int i = 0; i < columnCount; i++)
{
DataColumn dc = new DataColumn(tableHead[i]);
dt.Columns.Add(dc);
}
}
else
{
if (!String.IsNullOrEmpty(strLine))
{
aryLine = strLine.Split(',');
DataRow dr = dt.NewRow();
for (int j = 0; j < columnCount; j++)
{
dr[j] = aryLine[j];
}
dt.Rows.Add(dr);
}
}
}
if (aryLine != null && aryLine.Length > 0)
{
dt.DefaultView.Sort = tableHead[0] + " " + "asc";
}
sr.Close();
fs.Close();
return dt;
}
}
2、将数据库保存到数据库：
public static void TableValuedToDB(DataTable dt)
{
SqlConnection sqlConn = new SqlConnection(
ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString);
const string TSqlStatement =
"insert into table (col1,col2)" +
" SELECT nc.col1,nc.col2" +
" FROM @NewBulkTestTvp AS nc";
SqlCommand cmd = new SqlCommand(TSqlStatement, sqlConn);
SqlParameter catParam = cmd.Parameters.AddWithValue("@NewBulkTestTvp", dt);
catParam.SqlDbType = SqlDbType.Structured;
//表值参数的名字叫BulkUdt，在上面的建立测试环境的SQL中有。
catParam.TypeName = "dbo.BulkUdt";
try
{
sqlConn.Open();
if (dt != null && dt.Rows.Count != 0)
{
cmd.ExecuteNonQuery();
}
}
catch (Exception ex)
{
throw ex;
}
finally
{
sqlConn.Close();
}
}
3、在数据库创建表值参数类型:
create type dbo.BulkUdt(col1 bigint,col2 nvarchar(10));
4、开始导入数据：
Stopwatch sw = new Stopwatch();
string filePath = @"C:DB.csv";
DataTable dt = CSVFileHelper.OpenCSV(filePath);
sw.Start();
TableValuedToDB(dt);
sw.Stop();
Trace.WriteLine(string.Format("Elapsed Time is {0} Milliseconds", sw.ElapsedMilliseconds));