ODBC. Creating File DSN

If you have File DSN  on other Box you can copy *.dsn file and edit it if required.

How to find info about your PC

run from command line systeminfo

http://bshireesh.blogspot.ca/2008/11/know-configuration-of-your-pc.html

Useful links on SQL

Article about Using sp_who2

List of queries useful for troubleshooting SQL slowness (see 'Related Post' section)

How to truncate SQL Log

http://stackoverflow.com/questions/40402/what-is-the-command-to-truncate-a-sql-server-log-file

In management studio:

• Right-click the database, choose properties, then options.
• Make sure "Recovery model" is set to "Simple", not "Full"
• Click Ok
• Right-click the database again, choose tasks -> shrink files
• Change file type to "log"
• Click ok.

Alternatively, the SQL to do it:

 ALTER DATABASE mydatabase SET RECOVERY SIMPLE
 DBCC SHRINKFILE (mydatabase_Log, 1)

Ref: http://msdn.microsoft.com/en-us/library/ms189493.aspx

Process Monitoring Tools

1. Process Monitor v3.0.3

Process Monitor is an advanced system monitoring tool that enables you to monitor file system, Registry and process/thread activity in real-time. It offers filters and highlighting rules that enables you to limit and focus the... [Read more]

http://www.snapfiles.com/freeware/system/fwmonitor.html

Why cursor is a bad idea?

Cursor is a bad idea, since it lock a table used to populate a cursor while you loop through the cursor and do  some operation on fetched records.

Here is some article about it http://www.sqlbook.com/SQL/Avoiding-using-SQL-Cursors-20.aspx

Read Committed and Repetable Read

Good article on it in StackOverflow

1) The default isolation level of Read Committed means that Dirty Reads will not occur (although phantom or non-repeatable reads might). It does not guarantee that single rows are locked.

A non-repeatable read can occur in the following situation:

1. Transaction 1 begins2. Transaction 1 read a row3. Transaction 2 begins4. Transaction 2 changes the value of the same row read by Transaction 1
5. Transaction 2 commits6. Transaction 1 reads the row again. Transaction 1 has inconsistent data.

2) Repeatable Read isolation level means the above situation cannot occur (though phantom reads still might). A phantom read can occur in the following situation:

1. Transaction 1 begins2. Transaction 1 read a row3. Transaction 2 begins4. Transaction 2 deletes the row read by Transaction 1
5. Transaction 2 commits. Transaction 1 can no longer repeat its initial read, 
   since the row no longer exists.

If you want to guarantee that data does not chnage while you read it, you would need the Serializable isolation level. I would strongly advise agianst not using the Serializable isolation level unless you absolutely have to, as concurrency will suffer.

Schema comparasion tools

1. Red Gate Software

Creating new root certificate

In SSL communication you would need a certificate signed by recognized CA. You can generate the new certificate, but if it is not signed  by root certificate it would not be excepted. Is this possible to generate a root certificate without having access to recognized CA. The answer is yes

makecert -sv SignRoot.pvk -cy authority -r signroot.cer -a
    sha1 -n "CN=Dev Certification Authority" -ss my -sr localmachine

See article SSL with Self-hosted WCF Service for more detail. It also shows how to generate new certificate, sign it by the root certificate and associate it with a port.

Difference between cluster and cloud computing

Although these two paradigms are similar they can be distinguished be the following
1. clusters usually have corporate access, while clouds have public access through internet
2. clusters have not usage measurement, while clouds do and actually and it provide service by demand
3. resources are usually pre-reserved in clusters while in clouds they are demand driven (rapid elastic)

Here is a good article WHAT ARE THE DIFFERENCE BETWEEN CLOUD, CLUSTER AND GRID COMPUTING?

Tips and Triks

How To Show Full File Path in VS 2005 Title Bar

Unattended Service installation
     installUtil.exe /username=domain\username /password=password /unattended C:\My.exe

Useful commands/statements

1. Check if Procedure exist before creating it

EXISTS (SELECT * FROM sys.objects WHERE type = 'P' AND name = 'MyProc')

Return bool

Ex.

IF EXISTS (SELECT * FROM sys.objects WHERE type = 'P' AND name = 'MyProc')
DROP PROCEDURE MyProc
GO
CREATE PROCEDURE MyProc...

2.

SET NOCOUNT ON  - Stops the message indicating the number of rows affected by a Transact-SQL statement from being returned as part of the results.

For stored procedures that contain several statements that do not return much actual data, this can provide a significant performance boost because network traffic is greatly reduced.

3.  SP
 sp_help [object] provides info on object

Sharing files between VirtualBox host OS and and guest OS

How to share files between host OS and guest OS in VirtualBox.
Host OS: Windows 7
Guest OS: Linux version Ubuntu

Create Shared Folder. Settings -> Shared Folders. Click on add icon, specify Folder Path and Folder Name, check Auto-mount. Folder Path is path on Host OS to be shared. Folder Name is a reference used by guest OS.
VirtualBox will create folder sf-[Folder Name] under /media .
There is a pitfall here. This directory is not accessible. Access permission to this directory is  not given by default to the user who install VirtualBox and set up Shared Folder.
Here is instruction of how to grant the access permission to this directory (see )

1. Open a terminal.
2. Enter "su -" (without quotes), hit Enter.
3. Enter the root password, hit Enter.
4. Type in "usermod -a -G vboxsf username", without quotes, replacing username with the user you want to add to the group, hit Enter.
5. You may have to reboot to remount the share, the easiest way to do this is probably to reboot the VM.

Permutation algorithms

Find out all possible permutation of set of string.

We assume that a given set is lexicographical sorted set.

Algorithm of finding next permutation (we start with original element)
step 1 find left atom
step 2 find right element
step 3 swap
step 4 reverse the order of tail of index of left element (before swapping)


Find left atom. Start with next to the last atom. Move left until the current atom is less then next to it atom. This atom will be left atom.
Find right atom. Start with the last atom. Move left until the current element is great found  left element.

Example. Next to the element { "1" "3" "5" "4" "2" "0" }
                                                       |            |
1 step - left is "3", atoms[1] (current atom "5" less then "3")
2 step - right is "4", atoms[3] (atom "4" is great then "3")
3 step - "1" "4" "5" "3" "2" "0"
4 step - "1" "4" "0" "2" "3" "5" (reverse tail of atoms[1] )

Example.  A B C

1. left = B right = C.
    A C B -> A C B
2. left = A right = B
    B C A -> B A C
3. left = A right = C
    B C A -> B C A
5. left = B right = C
    C B A =>C A B
6. left = A right=B
    C B A => C B A

Code

public StringPerm Successor()
{
  StringPerm result = new StringPerm(this.element);
  int left, right;

  // Step #1 - Find left value 
  left = result.order - 2;  
  while ((result.element[left].CompareTo(result.element[left + 1])) >= 0
         && (left >= 1))
  {
    --left;
  }
  if ((left == 0) &&
      (this.element[left].CompareTo(this.element[left + 1])) >= 0)
  {
    return null;
  }

  // Step #2 - find right; first value > left
  right = result.order - 1;
  while (result.element[left].CompareTo(result.element[right]) >= 0)
  {
    --right;
  }

  // Step #3 - swap [left] and [right]
  string temp = result.element[left];
  result.element[left] = result.element[right];
  result.element[right] = temp;

  // Step #4 - reverse order the tail
  int i = left + 1;        
  int j = result.order - 1;
  while (i < j)
  {
    temp = result.element[i];
    result.element[i++] = result.element[j];
    result.element[j--] = temp;
  }

  return result;
}

Use recursion to get all permutation.

Here is a good article
   

How to get SID of Windows user group

Use utility psgetsid.exe. It is part  of PSTools package.

Ex. psgetsid.exe Adminitrator

Useful command

1. Run as
runas /user:mkalai [executable]

2. Start and stop remote service from command line

sc \\machine stop <service>

sc \\machine start <service>

Example
C:>net  start "Ariel Document Mailing Dispatch Services"
Y:\>sc \\cm-pp-mts01 start "Ariel Document Mailing Dispatch Services"
Y:\>sc \\cm-pp-mts01 stop "Ariel Document Mailing Dispatch Services"

3. Finding info about your PC
systeminfo

Tips for Launching WCF Test Client

When you create WCF Service Library project the command Debug gets set as follows
Start Action: Start Project
Start Options
      Command line arguments:  /client:"WcfTestClient.exe"

When you want to launch your own client set specify your executable for /client switch and set Working directory to where the executable resides

SQL error handling

Use try/catch to handle errors

BEGIN TRY
   . . .
END TRY
BEGIN CATCH
  ... (here you handle error and re-throw exception if you want. To throw exception you can do
       something like this RAISERROR('your error msg', 16, 1). Severity must be 16
END CATCH

The following system function provide error info. It can be used to format error message for logging or re-throwing within from CATCH block.

• ERROR_NUMBER() returns the number of the error.
• ERROR_SEVERITY() returns the severity.
• ERROR_STATE() returns the error state number.
• ERROR_PROCEDURE() returns the name of the stored procedure or trigger where the error occurred.
• ERROR_LINE() returns the line number inside the routine that caused the error.
• ERROR_MESSAGE() returns the complete text of the error message. The text includes the values supplied for any substitutable parameters, such as lengths, object names, or times.

How to query database schema and objects

Run select statement against system object information_schema.tables for tables list and information_schema.columns for columns list

Example

Select table_name from information_schema.tables where table_name like '%cust%'

Select column_name from information_schema.columns where table_name = 'customers'

Sp sp_help [object] can be also helpful

How to find stored procedure that contains the given text

SELECT DISTINCT so.name FROM sys.sysobjects so 

INNER JOIN sys.syscomments sc ON sc.id=so.id 

WHERE sc.TEXT LIKE '%your tesxt%'

Code First Migration Links

1. EF3 Code First Migration Walkthrough.            

 http://blogs.msdn.com/b/adonet/archive/2012/02/09/ef-4-3-code-based-migrations-walkthrough.aspx

This post will provide an overview of the functionality that is available inside of Visual Studio for interacting with migrations. We will focus on the code-based workflow for using migrations. In this workflow each change is written out to a code-based migration that can reside in your project.  

Main commands:

 Add-Migration <MigrationName>

 Update-Database

Run from Package Manager Console. Tools->Library Package Manager->Package Manager Console

2. Best books for SQL database
http://stackoverflow.com/questions/2413805/best-books-for-sql-server-database-design

                                                                                                                   

Glossary of Open Java Script and Web Frameworks from Scott Hanselman

http://www.hanselman.com/blog/TheBigGlossaryOfOpenSourceJavaScriptAndWebFrameworksWithCoolNames.aspx?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+ScottHanselman+%28Scott+Hanselman+-+ComputerZen.com%29

Reflector from RedGate

http://www.reflector.net/

Allows view, navigate, and search through the class hierarchies of .NET Assemblies even if you do not have the code for them.

Trial period 30 days.
Price: 70/130/190(VSPro)

Useful commands for Windows Administrators

http://www.robvanderwoude.com/ntadmincommands.php#Cmd13

How to read SQL error log

Run exec xp_readerrorlog

Keybord shortcut in Visual Studio

Navigator dialog box - Ctrl + comma

Optimistic concurrency in Entity Framework

To enable optimistic concurrency checking mark Entity property to be monitored for concurrency checking with attribute 'Concurrency Mode' as 'Fixed'. This can be done in properties window for a Entity property of interest in Entity Designer.

If any conflict occurs OptimisticConcurrencyException will be thrown. 

SSL access configuration for WCF

SSL will be used when Transport is set for wsHttpBinding

http://msdn.microsoft.com/en-us/library/ms731925.aspx

Apparently if mode is set to 'None' then any security requirements which would include SSL will be removed.

     <wsHttpBinding>

        <binding>

          <security mode="None">

            <transport clientCredentialType="None" />

          </security>

        </binding>

      </wsHttpBinding>