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Archive for July 2011

TECH: Encrypting a file

  1. In order to encrypt a file
    openssl des3 -e -k opensesame -in inputfile.tar -out outputfile.des3
    openssl aes-256-cbc -e -salt -k password -in inputfile.tar -out outputfile.enc
  2. In order to decrypt a file
    openssl des3 -d -k opensesame -in outputfile.des3 -out inputfile.tar
    openssl aes-256-cbc -d -salt -k password -in outputfile.dec -out origfile.tar
  3. Decrypt, Gunzip, untar in 1 step (and vice versa)
    openssl des3 -d -k opensesame -in input.tgz.des3  | gzip -c -d - | tar -xf -
    tar -cf - contentsDir | gzip -c - | openssl des3 -e -k opensesame -out output.tgz.des3

Written by curious

July 27, 2011 at 1:12 pm

Posted in tech-tips

Protected: IND: Madhushala

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Written by curious

July 19, 2011 at 12:11 pm

Posted in india

.NET: Bulk Inserts

Using Entity Framework and want to do a bulk copy to SQL Server database:

using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Transactions;

string bulkCopyConnStr = ConfigurationManager.ConnectionStrings["BulkOperations"].ConnectionString;

List<trade> trades = new List<trade>();
foreach (OptionTO inst in instruments)
  if (inst.value != null)
    var newTrade = new trade
      bookid = inst.bookId,
      strike = inst.K,
      impliedVol = inst.sigma

using (SqlConnection conn = new SqlConnection(bulkCopyConnStr))
  using (var tx = conn.BeginTransaction())
    SqlBulkCopy bc = new SqlBulkCopy(conn,
      SqlBulkCopyOptions.CheckConstraints |
      SqlBulkCopyOptions.FireTriggers |
      SqlBulkCopyOptions.KeepNulls, tx);
    bc.BatchSize = 10000;
    bc.DestinationTableName = "trade";

Note: this code uses EntityDataReader class for trades.AsDataReader() call.

You will ofcourse need to put this in your app.config

  <add name="BulkOperations" connectionString="data source=DBSERVER;Initial Catalog=DBINSTANCE;user id=DBUSER;password=DBPASSWD;MultipleActiveResultSets=True;persist security info=False;packet size=4096" providerName="" />

Written by curious

July 6, 2011 at 9:13 am

Posted in dotNET