我有一个类名为Entry
声明如下:
class Entry{
string Id {get;set;}
string Name {get;set;}
}
然后,将接受用于插入到使用ADO.NET数据库多个这样Entry
对象的方法:
static void InsertEntries(IEnumerable<Entry> entries){
//build a SqlCommand object
using(SqlCommand cmd = new SqlCommand()){
...
const string refcmdText = "INSERT INTO Entries (id, name) VALUES (@id{0},@name{0});";
int count = 0;
string query = string.Empty;
//build a large query
foreach(var entry in entries){
query += string.Format(refcmdText, count);
cmd.Parameters.AddWithValue(string.Format("@id{0}",count), entry.Id);
cmd.Parameters.AddWithValue(string.Format("@name{0}",count), entry.Name);
count++;
}
cmd.CommandText=query;
//and then execute the command
...
}
}
我的问题是这样的:我应该继续使用发送多重插入语句(建INSERT语句及其参数的一个巨大的字符串,并将其发送通过网络)的上述办法,还是应该保持开放的连接,并发送一个INSERT语句象这样的每Entry
:
using(SqlCommand cmd = new SqlCommand(){
using(SqlConnection conn = new SqlConnection(){
//assign connection string and open connection
...
cmd.Connection = conn;
foreach(var entry in entries){
cmd.CommandText= "INSERT INTO Entries (id, name) VALUES (@id,@name);";
cmd.Parameters.AddWithValue("@id", entry.Id);
cmd.Parameters.AddWithValue("@name", entry.Name);
cmd.ExecuteNonQuery();
}
}
}
你怎么看?会不会出现两者之间在SQL Server的性能差异?是否有任何其他后果,我应该知道的?
如果我是你,我不会使用其中任何一个。
第一个缺点是,如果在列表中值相同的参数名称可能会发生冲突。
第二个的缺点是,你为每个实体创建命令和参数。
最好的办法是让命令文本和构建一旦参数(使用Parameters.Add
添加参数)改变它们的值在循环并执行命令。这样,该语句将被一次准备。你开始循环之前,您还应该打开连接后它关闭。
static void InsertSettings(IEnumerable<Entry> settings) {
using (SqlConnection oConnection = new SqlConnection("Data Source=(local);Initial Catalog=Wip;Integrated Security=True")) {
oConnection.Open();
using (SqlTransaction oTransaction = oConnection.BeginTransaction()) {
using (SqlCommand oCommand = oConnection.CreateCommand()) {
oCommand.Transaction = oTransaction;
oCommand.CommandType = CommandType.Text;
oCommand.CommandText = "INSERT INTO [Setting] ([Key], [Value]) VALUES (@key, @value);";
oCommand.Parameters.Add(new SqlParameter("@key", SqlDbType.NChar));
oCommand.Parameters.Add(new SqlParameter("@value", SqlDbType.NChar));
try {
foreach (var oSetting in settings) {
oCommand.Parameters["@key"].Value = oSetting.Key;
oCommand.Parameters["@value"].Value = oSetting.Value;
if (oCommand.ExecuteNonQuery() != 1) {
//'handled as needed,
//' but this snippet will throw an exception to force a rollback
throw new InvalidProgramException();
}
}
oTransaction.Commit();
} catch (Exception) {
oTransaction.Rollback();
oConnection.Close();
throw;
}
}
}
}
}
你应该在每一个循环,而不是建立一个庞大的命令文本(顺便说一句,StringBuilder为该制造)的基础连接不会关闭并重新打开每个循环,让连接池管理器处理这个执行命令。看看这个链接进行进一步的信息:Tuning Up ADO.NET Connection Pooling in ASP.NET Applications
如果你想确保,每次执行命令成功,如果需要,你可以使用一个Transaction和回滚,
随访@Tim马伊 - 有两种可能的方式养活SqlBulkCopy的:一个DataReader或通过数据表。这里DataTable中的代码:
DataTable dt = new DataTable();
dt.Columns.Add(new DataColumn("Id", typeof(string)));
dt.Columns.Add(new DataColumn("Name", typeof(string)));
foreach (Entry entry in entries)
dt.Rows.Add(new string[] { entry.Id, entry.Name });
using (SqlBulkCopy bc = new SqlBulkCopy(connection))
{ // the following 3 lines might not be neccessary
bc.DestinationTableName = "Entries";
bc.ColumnMappings.Add("Id", "Id");
bc.ColumnMappings.Add("Name", "Name");
bc.WriteToServer(dt);
}
当很多条目考虑使用SqlBulkCopy。性能比一个系列的单刀片的速度要快得多。
您可以直接插入DataTable
是否正确创建它。
首先确保访问表列具有相同的列名和类型相似。然后你就可以使用这个功能,我相信这是非常快速和优雅。
public void AccessBulkCopy(DataTable table)
{
foreach (DataRow r in table.Rows)
r.SetAdded();
var myAdapter = new OleDbDataAdapter("SELECT * FROM " + table.TableName, _myAccessConn);
var cbr = new OleDbCommandBuilder(myAdapter);
cbr.QuotePrefix = "[";
cbr.QuoteSuffix = "]";
cbr.GetInsertCommand(true);
myAdapter.Update(table);
}
存储过程中插入使用单一插入多个记录:
ALTER PROCEDURE [dbo].[Ins]
@i varchar(50),
@n varchar(50),
@a varchar(50),
@i1 varchar(50),
@n1 varchar(50),
@a1 varchar(50),
@i2 varchar(50),
@n2 varchar(50),
@a2 varchar(50)
AS
INSERT INTO t1
SELECT @i AS Expr1, @i1 AS Expr2, @i2 AS Expr3
UNION ALL
SELECT @n AS Expr1, @n1 AS Expr2, @n2 AS Expr3
UNION ALL
SELECT @a AS Expr1, @a1 AS Expr2, @a2 AS Expr3
RETURN
后面的代码:
protected void Button1_Click(object sender, EventArgs e)
{
cn.Open();
SqlCommand cmd = new SqlCommand("Ins",cn);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("@i",TextBox1.Text);
cmd.Parameters.AddWithValue("@n",TextBox2.Text);
cmd.Parameters.AddWithValue("@a",TextBox3.Text);
cmd.Parameters.AddWithValue("@i1",TextBox4.Text);
cmd.Parameters.AddWithValue("@n1",TextBox5.Text);
cmd.Parameters.AddWithValue("@a1",TextBox6.Text);
cmd.Parameters.AddWithValue("@i2",TextBox7.Text);
cmd.Parameters.AddWithValue("@n2",TextBox8.Text);
cmd.Parameters.AddWithValue("@a2",TextBox9.Text);
cmd.ExecuteNonQuery();
cn.Close();
Response.Write("inserted");
clear();
}
ClsConectaBanco bd = new ClsConectaBanco();
StringBuilder sb = new StringBuilder();
sb.Append(" INSERT INTO FAT_BALANCETE ");
sb.Append(" ([DT_LANCAMENTO] ");
sb.Append(" ,[ID_LANCAMENTO_CONTABIL] ");
sb.Append(" ,[NR_DOC_CONTABIL] ");
sb.Append(" ,[TP_LANCAMENTO_GERADO] ");
sb.Append(" ,[VL_LANCAMENTO] ");
sb.Append(" ,[TP_NATUREZA] ");
sb.Append(" ,[CD_EMPRESA] ");
sb.Append(" ,[CD_FILIAL] ");
sb.Append(" ,[CD_CONTA_CONTABIL] ");
sb.Append(" ,[DS_CONTA_CONTABIL] ");
sb.Append(" ,[ID_CONTA_CONTABIL] ");
sb.Append(" ,[DS_TRIMESTRE] ");
sb.Append(" ,[DS_SEMESTRE] ");
sb.Append(" ,[NR_TRIMESTRE] ");
sb.Append(" ,[NR_SEMESTRE] ");
sb.Append(" ,[NR_ANO] ");
sb.Append(" ,[NR_MES] ");
sb.Append(" ,[NM_FILIAL]) ");
sb.Append(" VALUES ");
sb.Append(" (@DT_LANCAMENTO ");
sb.Append(" ,@ID_LANCAMENTO_CONTABIL ");
sb.Append(" ,@NR_DOC_CONTABIL ");
sb.Append(" ,@TP_LANCAMENTO_GERADO ");
sb.Append(" ,@VL_LANCAMENTO ");
sb.Append(" ,@TP_NATUREZA ");
sb.Append(" ,@CD_EMPRESA ");
sb.Append(" ,@CD_FILIAL ");
sb.Append(" ,@CD_CONTA_CONTABIL ");
sb.Append(" ,@DS_CONTA_CONTABIL ");
sb.Append(" ,@ID_CONTA_CONTABIL ");
sb.Append(" ,@DS_TRIMESTRE ");
sb.Append(" ,@DS_SEMESTRE ");
sb.Append(" ,@NR_TRIMESTRE ");
sb.Append(" ,@NR_SEMESTRE ");
sb.Append(" ,@NR_ANO ");
sb.Append(" ,@NR_MES ");
sb.Append(" ,@NM_FILIAL) ");
SqlCommand cmd = new SqlCommand(sb.ToString(), bd.CriaConexaoSQL());
bd.AbrirConexao();
cmd.Parameters.Add("@DT_LANCAMENTO", SqlDbType.Date);
cmd.Parameters.Add("@ID_LANCAMENTO_CONTABIL", SqlDbType.Int);
cmd.Parameters.Add("@NR_DOC_CONTABIL", SqlDbType.VarChar,255);
cmd.Parameters.Add("@TP_LANCAMENTO_GERADO", SqlDbType.VarChar,255);
cmd.Parameters.Add("@VL_LANCAMENTO", SqlDbType.Decimal);
cmd.Parameters["@VL_LANCAMENTO"].Precision = 15;
cmd.Parameters["@VL_LANCAMENTO"].Scale = 2;
cmd.Parameters.Add("@TP_NATUREZA", SqlDbType.VarChar, 1);
cmd.Parameters.Add("@CD_EMPRESA",SqlDbType.Int);
cmd.Parameters.Add("@CD_FILIAL", SqlDbType.Int);
cmd.Parameters.Add("@CD_CONTA_CONTABIL", SqlDbType.VarChar, 255);
cmd.Parameters.Add("@DS_CONTA_CONTABIL", SqlDbType.VarChar, 255);
cmd.Parameters.Add("@ID_CONTA_CONTABIL", SqlDbType.VarChar,50);
cmd.Parameters.Add("@DS_TRIMESTRE", SqlDbType.VarChar, 4);
cmd.Parameters.Add("@DS_SEMESTRE", SqlDbType.VarChar, 4);
cmd.Parameters.Add("@NR_TRIMESTRE", SqlDbType.Int);
cmd.Parameters.Add("@NR_SEMESTRE", SqlDbType.Int);
cmd.Parameters.Add("@NR_ANO", SqlDbType.Int);
cmd.Parameters.Add("@NR_MES", SqlDbType.Int);
cmd.Parameters.Add("@NM_FILIAL", SqlDbType.VarChar, 255);
cmd.Prepare();
foreach (dtoVisaoBenner obj in lista)
{
cmd.Parameters["@DT_LANCAMENTO"].Value = obj.CTLDATA;
cmd.Parameters["@ID_LANCAMENTO_CONTABIL"].Value = obj.CTLHANDLE.ToString();
cmd.Parameters["@NR_DOC_CONTABIL"].Value = obj.CTLDOCTO.ToString();
cmd.Parameters["@TP_LANCAMENTO_GERADO"].Value = obj.LANCAMENTOGERADO;
cmd.Parameters["@VL_LANCAMENTO"].Value = obj.CTLANVALORF;
cmd.Parameters["@TP_NATUREZA"].Value = obj.NATUREZA;
cmd.Parameters["@CD_EMPRESA"].Value = obj.EMPRESA;
cmd.Parameters["@CD_FILIAL"].Value = obj.FILIAL;
cmd.Parameters["@CD_CONTA_CONTABIL"].Value = obj.CONTAHANDLE.ToString();
cmd.Parameters["@DS_CONTA_CONTABIL"].Value = obj.CONTANOME.ToString();
cmd.Parameters["@ID_CONTA_CONTABIL"].Value = obj.CONTA;
cmd.Parameters["@DS_TRIMESTRE"].Value = obj.TRIMESTRE;
cmd.Parameters["@DS_SEMESTRE"].Value = obj.SEMESTRE;
cmd.Parameters["@NR_TRIMESTRE"].Value = obj.NRTRIMESTRE;
cmd.Parameters["@NR_SEMESTRE"].Value = obj.NRSEMESTRE;
cmd.Parameters["@NR_ANO"].Value = obj.NRANO;
cmd.Parameters["@NR_MES"].Value = obj.NRMES;
cmd.Parameters["@NM_FILIAL"].Value = obj.NOME;
cmd.ExecuteNonQuery();
rowAffected++;
}