Bulk Insert into SQL Server 2008 - sql-server-2008

Question

for (int i = 0; i < myClass.Length; i++)
{
string upSql = "UPDATE CumulativeTable SET EngPosFT = #EngPosFT,EngFTAv=#EngFTAv WHERE RegNumber =#RegNumber AND Session=#Session AND Form=#Form AND Class=#Class";
SqlCommand cmdB = new SqlCommand(upSql, connection);
cmdB.CommandTimeout = 980000;
cmdB.Parameters.AddWithValue("#EngPosFT", Convert.ToInt32(Pos.GetValue(i)));
cmdB.Parameters.AddWithValue("#RegNumber", myClass.GetValue(i));
cmdB.Parameters.AddWithValue("#EngFTAv", Math.Round((engtot / arrayCount), 2));
cmdB.Parameters.AddWithValue("#Session", drpSess.SelectedValue);
cmdB.Parameters.AddWithValue("#Form", drpForm.SelectedValue);
cmdB.Parameters.AddWithValue("#Class", drpClass.SelectedValue);
int idd = Convert.ToInt32(cmdB.ExecuteScalar());
}
assuming myClass.Length is 60. This does 60 update statements. How can I limit it to 1 update statement. Please code example using the above code will be appreciated. Thanks
Tried using this
StringBuilder command = new StringBuilder();
SqlCommand cmdB = null;
for (int i = 0; i < myClass.Length; i++)
{
command.Append("UPDATE CumulativeTable SET" + " EngPosFT = " + Convert.ToInt32(Pos.GetValue(i)) + "," + " EngFTAv = " + Math.Round((engtot / arrayCount), 2) +
" WHERE RegNumber = " + myClass.GetValue(i) + " AND Session= " + drpSess.SelectedValue + " AND Form= " + drpForm.SelectedValue + " AND Class= " + drpClass.SelectedValue + ";");
//or command.AppendFormat("UPDATE CumulativeTable SET EngPosFT = {0},EngFTAv={1} WHERE RegNumber ={2} AND Session={3} AND Form={4} AND Class={5};", Convert.ToInt32(Pos.GetValue(i)), Math.Round((engtot / arrayCount), 2), myClass.GetValue(i), drpSess.SelectedValue, drpForm.SelectedValue, drpClass.SelectedValue);
}//max length is 128 error is encountered

Answer 1

Look at the BULK INSERT T-SQL command. But since I don't have a lot of personal experience with that command, I do see some immediate opportunity to improve this code using the same sql by creating the command and parameters outside of the loop, and only making the necessary changes inside the loop:
string upSql = "UPDATE CumulativeTable SET EngPosFT = #EngPosFT,EngFTAv=#EngFTAv WHERE RegNumber =#RegNumber AND Session=#Session AND Form=#Form AND Class=#Class";
SqlCommand cmdB = new SqlCommand(upSql, connection);
cmdB.CommandTimeout = 980000;
//I had to guess at the sql types you used here.
//Adjust this to match your actual column data types
cmdB.Parameters.Add("#EngPosFT", SqlDbType.Int);
cmdB.Parameters.Add("#RegNumber", SqlDbType.Int);
//It's really better to use explicit types here, too.
//I'll just update the first parameter as an example of how it looks:
cmdB.Parameters.Add("#EngFTAv", SqlDbType.Decimal).Value = Math.Round((engtot / arrayCount), 2));
cmdB.Parameters.AddWithValue("#Session", drpSess.SelectedValue);
cmdB.Parameters.AddWithValue("#Form", drpForm.SelectedValue);
cmdB.Parameters.AddWithValue("#Class", SqlDbTypedrpClass.SelectedValue);
for (int i = 0; i < myClass.Length; i++)
{
cmdB.Parameters[0].Value = Convert.ToInt32(Pos.GetValue(i)));
cmdB.Parameters[1].Value = myClass.GetValue(i));
int idd = Convert.ToInt32(cmdB.ExecuteScalar());
}

Answer 2

It would be better in this case to create a stored procedure that accepts a Table Valued Parameter. On the .NET side of things, you create a DataTable object containing a row for each set of values you want to use.
On the SQL Server side of things, you can treat the parameter as another table in a query. So inside the stored proc, you'd have:
UPDATE a
SET
EngPosFT = b.EngPosFT,
EngFTAv=b.EngFTAv
FROM
CumulativeTable a
inner join
#MyParm b
on
a.RegNumber =b.RegNumber AND
a.Session=b.Session AND
a.Form=b.Form AND
a.Class=b.Class
Where #MyParm is your table valued parameter.
This will then be processed as a single round-trip to the server.

Answer 3

In such scenarios it is always best to write a Stored Procedure and call that stored proc in the for loop, passing the necessary arguments at each call.

Answer 4

using System;
using System.Data;
using System.Data.SqlClient;
namespace DataTableExample
{
class Program
{
static void Main(string[] args)
{
DataTable prodSalesData = new DataTable("ProductSalesData");
// Create Column 1: SaleDate
DataColumn dateColumn = new DataColumn();
dateColumn.DataType = Type.GetType("System.DateTime");
dateColumn.ColumnName = "SaleDate";
// Create Column 2: ProductName
DataColumn productNameColumn = new DataColumn();
productNameColumn.ColumnName = "ProductName";
// Create Column 3: TotalSales
DataColumn totalSalesColumn = new DataColumn();
totalSalesColumn.DataType = Type.GetType("System.Int32");
totalSalesColumn.ColumnName = "TotalSales";
// Add the columns to the ProductSalesData DataTable
prodSalesData.Columns.Add(dateColumn);
prodSalesData.Columns.Add(productNameColumn);
prodSalesData.Columns.Add(totalSalesColumn);
// Let's populate the datatable with our stats.
// You can add as many rows as you want here!
// Create a new row
DataRow dailyProductSalesRow = prodSalesData.NewRow();
dailyProductSalesRow["SaleDate"] = DateTime.Now.Date;
dailyProductSalesRow["ProductName"] = "Nike";
dailyProductSalesRow["TotalSales"] = 10;
// Add the row to the ProductSalesData DataTable
prodSalesData.Rows.Add(dailyProductSalesRow);
// Copy the DataTable to SQL Server using SqlBulkCopy
using (SqlConnection dbConnection = new SqlConnection("Data Source=ProductHost;Initial Catalog=dbProduct;Integrated Security=SSPI;Connection Timeout=60;Min Pool Size=2;Max Pool Size=20;"))
{
dbConnection.Open();
using (SqlBulkCopy s = new SqlBulkCopy(dbConnection))
{
s.DestinationTableName = prodSalesData.TableName;
foreach (var column in prodSalesData.Columns)
s.ColumnMappings.Add(column.ToString(), column.ToString());
s.WriteToServer(prodSalesData);
}
}
}
}
}