switch(System.Type.GetTypeCode(dt.Rows[i][j].GetType())) { case System.TypeCode.Byte: case System.TypeCode.Char: case System.TypeCode.Decimal: case System.TypeCode.Double: case System.TypeCode.Int16: case System.TypeCode.Int32: case System.TypeCode.Int64: case System.TypeCode.SByte: case System.TypeCode.Single: case System.TypeCode.UInt16: case System.TypeCode.UInt32: case System.TypeCode.UInt64: valueStr += dt.Rows[i][j].ToString() +","; break; case System.TypeCode.DateTime: case System.TypeCode.String: valueStr += "'" + dt.Rows[i][j].ToString() +"',"; break; case System.TypeCode.Boolean: { if ((bool)dt.Rows[i][j]==true) valueStr += "1,"; else valueStr += "0,"; break; } default: valueStr +=" null,"; break; } }
将DataTable的TableName属性设置为数据库中表的名称,然后调用该方法public static string ExecuteInsert(DataTable dt)
{
string sql="";
string fieldStr="";
string valueStr="";
int i=0;
try
{
for(i=0;i<dt.Columns.Count;i++)
{
fieldStr += dt.Columns[i].ColumnName + ",";
} fieldStr = fieldStr.Substring(0,fieldStr.Length-1);
for(i=0;i<dt.Rows.Count;i++)
{
sql = "insert into {0}({1}) values({2})";
valueStr ="";
for(int j=0;j<dt.Columns.Count;j++)
{
switch(System.Type.GetTypeCode(dt.Rows[i][j].GetType()))
{
case System.TypeCode.Byte:
case System.TypeCode.Char:
case System.TypeCode.Decimal:
case System.TypeCode.Double:
case System.TypeCode.Int16:
case System.TypeCode.Int32:
case System.TypeCode.Int64:
case System.TypeCode.SByte:
case System.TypeCode.Single:
case System.TypeCode.UInt16:
case System.TypeCode.UInt32:
case System.TypeCode.UInt64:
valueStr += dt.Rows[i][j].ToString() +",";
break;
case System.TypeCode.DateTime:
case System.TypeCode.String:
valueStr += "'" + dt.Rows[i][j].ToString() +"',";
break;
case System.TypeCode.Boolean:
{
if ((bool)dt.Rows[i][j]==true)
valueStr += "1,";
else
valueStr += "0,"; break;
}
default:
valueStr +=" null,";
break;
}
}
valueStr = valueStr.Substring(0,valueStr.Length-1);
sql = string.Format(sql,dt.TableName,fieldStr,valueStr);
ExecuteNonQuery(sql);
}
return "ok";
} catch(Exception ex)
{
return ex.Message; }
}
SqlConnection myConnection = New SqlConnection(strConn) ;
SqlDataAdapter adapterupdate2 = New SqlDataAdapter ;
For int = 1 To i
String strInsertMes ;
String N_Time ;
strInsertMes = "insert into BOMD values("
strInsertMes += "'" & CODP_ITEM.Text & "'"
strInsertMes += "," & "'" & L_datatable.Rows(int - 1).Item(0) & "'"
strInsertMes += "," & "'" & L_datatable.Rows(int - 1).Item(1) & "'"
strInsertMes += "," & "'" & L_datatable.Rows(int - 1).Item(2) & "'"
strInsertMes += "," & "'" & L_datatable.Rows(int - 1).Item(3) & "'"
strInsertMes += "," & "'" & L_datatable.Rows(int - 1).Item(4) & "'"
strInsertMes += "," & "'" & L_datatable.Rows(int - 1).Item(5) & "'"
strInsertMes += "," & "'" & L_datatable.Rows(int - 1).Item(6) & "'"
strInsertMes += "," & "'" & L_datatable.Rows(int - 1).Item(7) & "'"
strInsertMes += "," & "'" & type & "'"
strInsertMes += ")"
adapterupdate2.SelectCommand = New SqlCommand(strInsertMes, myConnection)
adapterupdate2.SelectCommand.ExecuteNonQuery()
Next int
在.Net1.1中无论是对于批量插入整个DataTable中的所有数据到数据库中,还是进行不同数据源之间的迁移,都不是很方便。而在.Net2.0中,SQLClient命名空间下增加了几个新类帮助我们通过DataTable或DataReader批量迁移数据。数据源可以来自关系数据库或者XML文件,甚至WebService返回结果。其中最重要的一个类就是SqlBulkCopy类,使用它可以很方便的帮助我们把数据源的数据迁移到目标数据库中。
下面我们先通过一个简单的例子说明这个类的使用:DateTime startTime;
protected void Button1_Click(object sender, EventArgs e)
{
startTime = DateTime.Now;
string SrcConString;
string DesConString;
SqlConnection SrcCon = new SqlConnection();
SqlConnection DesCon = new SqlConnection();
SqlCommand SrcCom = new SqlCommand();
SqlDataAdapter SrcAdapter = new SqlDataAdapter();
DataTable dt = new DataTable();
SrcConString =
ConfigurationManager.ConnectionStrings["SrcDBConnectionString"].ConnectionString;
DesConString =
ConfigurationManager.ConnectionStrings["DesDBConnectionString"].ConnectionString;
SrcCon.ConnectionString = SrcConString;
SrcCom.Connection = SrcCon;
SrcCom.CommandText = " SELECT * From [SrcTable]";
SrcCom.CommandType = CommandType.Text;
SrcCom.Connection.Open();
SrcAdapter.SelectCommand = SrcCom;
SrcAdapter.Fill(dt);
SqlBulkCopy DesBulkOp;
DesBulkOp = new SqlBulkCopy(DesConString,
SqlBulkCopyOptions.UseInternalTransaction);
DesBulkOp.BulkCopyTimeout = 500000000;
DesBulkOp.SqlRowsCopied +=
new SqlRowsCopiedEventHandler(OnRowsCopied);
DesBulkOp.NotifyAfter = dt.Rows.Count;
try
{
DesBulkOp.DestinationTableName = "SrcTable";
DesBulkOp.WriteToServer(dt);
}
catch (Exception ex)
{
lblResult.Text = ex.Message;
}
finally
{
SrcCon.Close();
DesCon.Close();
}
}
private void OnRowsCopied(object sender, SqlRowsCopiedEventArgs args)
{
lblCounter.Text += args.RowsCopied.ToString() + " rows are copied<Br>";
TimeSpan copyTime = DateTime.Now - startTime;
lblCounter.Text += "Copy Time:" + copyTime.Seconds.ToString() + "." + copyTime.Milliseconds.ToString() + " seconds";
}
接着具体分析这几行代码:
SqlBulkCopy DesBulkOp;
DesBulkOp = new SqlBulkCopy(DesConString, SqlBulkCopyOptions.UseInternalTransaction);先生成SqlBulkCopy 实例,构造函数指定了目标数据库,使用SqlBulkCopyOptions.UseInternalTransaction是指迁移动作指定在一个Transaction当中,如果数据迁移中产生错误或异常将发生回滚。其他选项请参考MSDN。
DesBulkOp.BulkCopyTimeout = 500000000;
指定操作完成的Timeout时间
DesBulkOp.SqlRowsCopied += new SqlRowsCopiedEventHandler(OnRowsCopied);
DesBulkOp.NotifyAfter = dt.Rows.Count;
try
{
DesBulkOp.DestinationTableName = "SrcTable";
DesBulkOp.WriteToServer(dt);
}
NotifyAfter属性指定通知通知事件前处理的数据行数,在这里指定为表的行数,并添加SqlRowsCopied事件输出整个迁移过程的时间。WriteToServer方法就是将数据源拷备到目标数据库。在使用WriteToServer方法之前必须先指定DestinationTableName属性,也就是目标数据库的表名,
我们还可以自己定义一个Transaction,例如:
SqlTransaction Transaction;
Transaction =
SrcCom.Connection.BeginTransaction();
SqlBulkCopy DesBulkOp;
DesBulkOp = new SqlBulkCopy(new SqlConnection(DesConString),
SqlBulkCopyOptions.Default,
Transaction);
try
{
//..
}
catch{}
finally
{
Transaction.Commit();
}
另外还有一个SqlBulkCopyColumnMapping类,可以让数据源字段映射到目标数据中命名不同的字段上。也就是说如果目标数据和源数据的列名不同时,可以用这个类进行映射:
SqlBulkCopyColumnMapping ColMap = new SqlBulkCopyColumnMapping("SrcCol", "DesCol");
DesBulkOp.ColumnMappings.Add(ColMap);
或者可以直接添加映射:
DesBulkOp.ColumnMappings.Add("SrcCol", "DesCol");
性能问题:
我使用上面的例子测试,迁移了2万条左右的记录,花的时间不到一秒,应改说性能还是不错的。另外,使用SQL Profile监视迁移事件,可以看见请求记录非常少,只有几条而已。据说使用SqlBulkCopy可以大大减少数据迁移的时间