I have a class named Entry declared like this:
class Entry{
string Id {get;set;}
string Name {get;set;}
}
and then a method that will accept multiple such Entry objects for insertion into the database using ADO.NET:
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
...
}
}
And my question is this: should I keep using the above way of sending multiple insert statements (build a giant string of insert statements and their parameters and send it over the network), or should I keep an open connection and send a single insert statement for each Entry like this:
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();
}
}
}
What do you think? Will there be a performance difference in the Sql Server between the two? Are there any other consequences I should be aware of?
This question is related to
c#
sql-server-2005
ado.net
multiple-insert
If I were you I would not use either of them.
The disadvantage of the first one is that the parameter names might collide if there are same values in the list.
The disadvantage of the second one is that you are creating command and parameters for each entity.
The best way is to have the command text and parameters constructed once (use Parameters.Add to add the parameters) change their values in the loop and execute the command. That way the statement will be prepared only once. You should also open the connection before you start the loop and close it after it.
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++;
}
You can directly insert a DataTable if it is created correctly.
First make sure that the access table columns have the same column names and similar types. Then you can use this function which I believe is very fast and elegant.
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);
}
Following up @Tim Mahy - There's two possible ways to feed SqlBulkCopy: a DataReader or via DataTable. Here the code for DataTable:
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);
}
When it are a lot of entries consider to use SqlBulkCopy. The performance is much faster than a series of single inserts.
You should execute the command on every loop instead of building a huge command Text(btw,StringBuilder is made for this) The underlying Connection will not close and re-open for each loop, let the connection pool manager handle this. Have a look at this link for further informations: Tuning Up ADO.NET Connection Pooling in ASP.NET Applications
If you want to ensure that every command is executed successfully you can use a Transaction and Rollback if needed,
Stored procedure to insert multiple records using single insertion:
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
Code behind:
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();
}
The truly terrible way to do it is to execute each INSERT statement as its own batch:
Batch 1:
INSERT INTO Entries (id, name) VALUES (1, 'Ian Boyd);
Batch 2:
INSERT INTO Entries (id, name) VALUES (2, 'Bottlenecked);
Batch 3:
INSERT INTO Entries (id, name) VALUES (3, 'Marek Grzenkowicz);
Batch 4:
INSERT INTO Entries (id, name) VALUES (4, 'Giorgi);
Batch 5:
INSERT INTO Entries (id, name) VALUES (5, 'AMissico);
Note: Parameterization, error checking, and any other nit-picks elided for expoistory purposes.
This is truly, horrible, terrible way to do things. It gives truely awful performance, because you suffer the network round-trip-time every time.
A much better solution is to batch all the INSERT statements into one batch:
Batch 1:
INSERT INTO Entries (id, name) VALUES (1, 'Ian Boyd');
INSERT INTO Entries (id, name) VALUES (2, 'Bottlenecked');
INSERT INTO Entries (id, name) VALUES (3, 'Marek Grzenkowicz');
INSERT INTO Entries (id, name) VALUES (4, 'Giorgi');
INSERT INTO Entries (id, name) VALUES (5, 'AMissico');
This way you only suffer one-round trip. This version has huge performance wins; on the order of 5x faster.
Even better is to use the VALUES clause:
INSERT INTO Entries (id, name)
VALUES
(1, 'Ian Boyd'),
(2, 'Bottlenecked'),
(3, 'Marek Grzenkowicz'),
(4, 'Giorgi'),
(5, 'AMissico');
This gives you some performance improvements over the 5 separate INSERTs version; it lets the server do what it's good at: operating on sets:
SQL Sever loves to operate on sets of data; it's where it's a viking!
The above T-SQL examples have all the parameteriztion stuff removed for clarity. But in reality you want to parameterize queries
But Bruno has an important point; SQL Server's driver only lets you include 2,100 parameters in a batch. The above query has two values:
@id, @name
If you import 1,051 rows in a single batch, that's 2,102 parameters - you'll get the error:
Too many parameters were provided in this RPC request
That is why i generally insert 5 or 10 rows at a time. Adding more rows per batch doesn't improve performance that much - there's diminishing returns.
It keeps the number of parameters low, it doesn't get anywhere near the T-SQL batch size limit. There's also the fact that a VALUES clause is limited to 1000 tuples anyway.
Your first approach is good, but you do have the issues of:
So the goal is to generate a string such as:
INSERT INTO Entries (id, name) VALUES
(@p1, @p2),
(@p3, @p4),
(@p5, @p6),
(@p7, @p8),
(@p9, @p10)
I'll change your code by the seat of my pants
IEnumerable<Entry> entries = GetStuffToInsert();
SqlCommand cmd = new SqlCommand();
StringBuilder sql = new StringBuilder();
Int32 batchSize = 0; //how many rows we have build up so far
Int32 p = 1; //the current paramter name (i.e. "@p1") we're going to use
foreach(var entry in entries)
{
//Build the names of the parameters
String pId = String.Format("@p{0}", p); //the "Id" parameter name (i.e. "p1")
String pName = String.Format("@p{0}", p+1); //the "Name" parameter name (i.e. "p2")
p += 2;
//Build a single "(p1, p2)" row
String row = String.Format("({0}, {1})", pId, pName); //a single values tuple
//Add the row to our running SQL batch
if (batchSize > 0)
sb.AppendLine(",");
sb.Append(row);
batchSize += 1;
//Add the parameter values for this row
cmd.Parameters.Add(pID, System.Data.SqlDbType.Int ).Value = entry.Id;
cmd.Parameters.Add(pName, System.Data.SqlDbType.String).Value = entry.Name;
if (batchSize >= 5)
{
String sql = "INSERT INTO Entries (id, name) VALUES"+"\r\n"+
sb.ToString();
cmd.CommandText = sql;
cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
sb.Clear();
batchSize = 0;
p = 1;
}
}
//handle the last few stragglers
if (batchSize > 0)
{
String sql = "INSERT INTO Entries (id, name) VALUES"+"\r\n"+
sb.ToString();
cmd.CommandText = sql;
cmd.ExecuteNonQuery();
}
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[0].Value = oSetting.Key;
oCommand.Parameters[1].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();
throw;
}
}
}
}
}
Source: Stackoverflow.com