Starbuck

Authentication vs. Authorization

2011-03-18T11:19:00.000-07:00

I was asked this question at one of my job interviews. So I decided to look it up and settle it once and for all.

Authentication is the mechanism where the system may securely identify their users. Basically the system asks:

* Who is the user?
* Is the user really who he/she represents himself to be?

The answers to these questions are unique information known only between the user and the system. Examples include password, finger print, retinal scan...etc.

Authorization is the mechanism where the system determines the level of access to grant an authenticated user. In a nut shell, the system asks:

* Is user X authorized to access resource R?
* Is user X authorized to perform operation P?
* Is user X authorized to perform operation P on resource R?

CSS - when to use class, id?

2011-03-14T07:49:00.000-07:00

Use IDs when there is only one occurrence per page (eg. menu, content pane, banner). Use classes when there are one or more occurrences per page.

Query to generate table with all dates between date range

2011-03-09T13:53:00.000-08:00

This crazy query basically creates 2 temporarily tables:
1. table with all dates between date range
2. table with data we want

These 2 table are then joined to give the number of requests made group by day.

here it goes...

SELECT CONVERT(varchar(10), derivedtbl_1.date, 101) AS date,
derivedtbl_2.count

FROM (SELECT DISTINCT TOP (100) PERCENT DATEADD(dd, Days.Row, DATEADD(mm, Months.Row, DATEADD(yy, Years.Row, @startDate))) AS date
FROM (SELECT 0 AS Row
UNION ALL
SELECT 1 AS Expr1
UNION ALL
SELECT 2 AS Expr1
UNION ALL
SELECT 3 AS Expr1
UNION ALL
SELECT 4 AS Expr1
UNION ALL
SELECT 5 AS Expr1
UNION ALL
SELECT 6 AS Expr1
UNION ALL
SELECT 7 AS Expr1
UNION ALL
SELECT 8 AS Expr1
UNION ALL
SELECT 9 AS Expr1
UNION ALL
SELECT 10 AS Expr1
UNION ALL
SELECT 11 AS Expr1
UNION ALL
SELECT 12 AS Expr1
UNION ALL
SELECT 13 AS Expr1
UNION ALL
SELECT 14 AS Expr1
UNION ALL
SELECT 15 AS Expr1
UNION ALL
SELECT 16 AS Expr1
UNION ALL
SELECT 17 AS Expr1
UNION ALL
SELECT 18 AS Expr1
UNION ALL
SELECT 19 AS Expr1
UNION ALL
SELECT 20 AS Expr1) AS Years INNER JOIN
(SELECT 0 AS Row
UNION ALL
SELECT 1 AS Expr1
UNION ALL
SELECT 2 AS Expr1
UNION ALL
SELECT 3 AS Expr1
UNION ALL
SELECT 4 AS Expr1
UNION ALL
SELECT 5 AS Expr1
UNION ALL
SELECT 6 AS Expr1
UNION ALL
SELECT 7 AS Expr1
UNION ALL
SELECT 8 AS Expr1
UNION ALL
SELECT 9 AS Expr1
UNION ALL
SELECT 10 AS Expr1
UNION ALL
SELECT 11 AS Expr1) AS Months ON DATEADD(mm, Months.Row, DATEADD(yy, Years.Row, @startDate)) <= @endDate INNER JOIN
(SELECT 0 AS Row
UNION ALL
SELECT 1 AS Expr1
UNION ALL
SELECT 2 AS Expr1
UNION ALL
SELECT 3 AS Expr1
UNION ALL
SELECT 4 AS Expr1
UNION ALL
SELECT 5 AS Expr1
UNION ALL
SELECT 6 AS Expr1
UNION ALL
SELECT 7 AS Expr1
UNION ALL
SELECT 8 AS Expr1
UNION ALL
SELECT 9 AS Expr1
UNION ALL
SELECT 10 AS Expr1
UNION ALL
SELECT 11 AS Expr1
UNION ALL
SELECT 12 AS Expr1
UNION ALL
SELECT 13 AS Expr1
UNION ALL
SELECT 14 AS Expr1
UNION ALL
SELECT 15 AS Expr1
UNION ALL
SELECT 16 AS Expr1
UNION ALL
SELECT 17 AS Expr1
UNION ALL
SELECT 18 AS Expr1
UNION ALL
SELECT 19 AS Expr1
UNION ALL
SELECT 20 AS Expr1
UNION ALL
SELECT 21 AS Expr1
UNION ALL
SELECT 22 AS Expr1
UNION ALL
SELECT 23 AS Expr1
UNION ALL
SELECT 24 AS Expr1
UNION ALL
SELECT 25 AS Expr1
UNION ALL
SELECT 26 AS Expr1
UNION ALL
SELECT 27 AS Expr1
UNION ALL
SELECT 28 AS Expr1
UNION ALL
SELECT 29 AS Expr1
UNION ALL
SELECT 30 AS Expr1) AS Days
ON DATEADD(dd, Days.Row, DATEADD(mm, Months.Row, DATEADD(yy, Years.Row, @startDate))) <= @endDate
WHERE (DATEADD(yy, Years.Row, @startDate) <= @endDate)
ORDER BY date) AS derivedtbl_1

LEFT OUTER JOIN

(SELECT COUNT(*) AS count, CONVERT(varchar(10), b.DateRequested, 101) AS date

FROM [TDBK-SQLDA-CX13.P-TDBFG.COM\CX13].[IS].dbo.T_Team101_Request_Assistance_Group a INNER JOIN
[TDBK-SQLDA-CX13.P-TDBFG.COM\CX13].[IS].dbo.T_Team101_Request_Assistance b ON a.RequestID = b.id INNER JOIN
[TDBK-SQLDA-CX13.P-TDBFG.COM\CX13].[IS].dbo.T_C_Team101_Groups c ON a.Team101ID = c.id

WHERE (b.DateRequested <= DATEADD(day, 1, @endDate)) AND
(b.DateRequested >= @startDate) AND
(c.GroupName = @group)

GROUP BY b.DateRequested) AS derivedtbl_2

ON CONVERT(varchar(10), derivedtbl_1.date, 101) = CONVERT(varchar(10), derivedtbl_2.date, 101)

Reportviewer print - blank pages

2011-02-24T13:43:00.000-08:00

If a blank page is inserted after printing each page of a report (created with the Reportviewer control in Visual Studio 2010), narrow the width of the report in .rdlc file.

Learning stored procedures

2011-02-18T08:30:00.000-08:00

Advantages of sp:
- capable of handling very complex queries
- utilizes resources of the db server not the app server
- convenient for moving app from platfrom to platform - business logic stays with the db

Sp structure:
CREATE PROCEDURE [PROCEDURE NAME]

/*
variables:
@variableName type
*/

AS

/*
SQL statements
*/

What is ADO .NET Entity Framework

2011-02-16T07:29:00.000-08:00

- a set of data access APIs
- targeting ADO .NET 4.0
- EFv4 (2nd edition) shipped with .NET 4.0 and VS 2010
- Entity Data Model is treated indepenently from its underlying datastore

WHAT IS LINQ??

- stands for Language Integrated Query
- able to query objects, ADO .NET (dataset, database, entities), XML

LINQ - http://msdn.microsoft.com/en-us/magazine/cc337893.aspx

LINQ to Entities - http://www.linqdev.com/PublicPortal/publicportal/linq-to-entities.aspx

a test to make sure I'm off the Seneca feed list

2011-02-15T14:52:00.000-08:00

My copy command

2009-12-06T22:09:00.000-08:00

This can only handle a line of 1500 characters...

#include
#include
#define LINESIZE 1500+1

int main(int argc, char *argv[]) {
FILE *src;
FILE *dest;
src = fopen (argv[1], "r");
dest = fopen (argv[2], "w");
char sf[LINESIZE];

if (src) {
while (1 == fscanf(src, "%[^\n]\n", sf)) {
sf[strlen(sf)+1] = '\0';
fprintf(dest, "%s\n", sf);
}
fclose(src);
}
else {
printf("Cannot open source file.\n");
}
fclose(dest);
return 0;
}

Printing a file backwards

2009-12-06T22:07:00.000-08:00

int main(){
Student S;
fstream fback("std.bin",ios::in| ios::binary);
fback.seekg(-(sizeof(Student)), ios::end);
while (!fback.read((char *)&S, sizeof(Student)).fail()) {
cout << S << endl;
fback.seekg(-2 * (sizeof(Student)), ios::cur);
}
return 0;
}

++, --: yet another prove why they should be avoided

2009-11-29T21:52:00.000-08:00

I was doing a walk through from one the old tests:

x = -2.1;

after the line...

x = -x++;

3 compilers assigned 3 different values to x:

VC++: 3.1 - incremented, negated (not necessarily in this order), assigned
linux: -1.1 - incremented, assigned (why never negated?)
borland: 2.1 - negated, assigned (never incremented)

io_checklist with comments

2009-11-23T19:08:00.000-08:00

I added some comments to setItems() in io_checklist:

void IO_CheckList::setItems(const char *str){
int i;
unsigned int maxlen = 0;
int strLen= strlen((char*)str);
_itemstr = new char[strLen+1];
strcpy(_itemstr, (char*)str); // copy str into _itemstr
for(_len = 0,i=0;i if(_itemstr[i] == '\n'){
_len++; // number of items separated by '\n'
}
}
_items = new char*[_len+1]; //_items is pointer to an array of pointer
_status = new bool[_len+1];
for(i=0;i<_len+1;i++){
_status[i] = false;
}

/* Following lines of code:
_itemstr contains a string of items in the checklist, each one separated by '\n';
_items is made to point to the beginning of the string before the for loop;
Through the for loop, _itemstr is cycled through character by character.
Each time a '\n' is reached, _item is made to point to the character after the '\n'.
The '\n' is replaced with NULL and thus truncating the rest of the string so _item pointer in the array of pointers points to only 1 item in the checklist. */

_items[0] = _itemstr; // point to where _itemstr is pointing to
for(_len = 1,i=0;i if(_itemstr[i] == '\n'){
_items[_len]=&_itemstr[i+1]; // when '\n' is reached, _item points to first character after '\n'
_itemstr[i] = 0; // replace '\n' with NULL
if(strlen(_items[_len-1])> maxlen){
maxlen = strlen(_items[_len-1]); // keep track of the longest string copied
}
_len++; // keep track of number of items
}
}
if(strlen(_items[_len-1])> maxlen){
maxlen = strlen(_items[_len-1]);
}
IO_Frame::set(IO_Field::getRow(), IO_Field::getCol(), maxlen + 6, _len+2);
_titlelen = maxlen;
}

Assignment 2 progress

2009-11-17T21:49:00.000-08:00

Just committed io_field (probably the easiest class for this assignment =P)- it's now done according to spec on wiki. The only kinks I ran into was trying to get the value of

_owner->getTop()
_owner->getLeft()

Since getTop() and getLeft() are functions of io_frame, _owner is an io_form pointer but inherits from io_frame I had to make sure that the inheritance is declared.

My next step is to look through io_checklist because Fardad said that there may be some extra functions that need to be added to io_field.

Delayed blog - first 2 IRC meetings

2009-11-05T16:13:00.000-08:00

This is a little delayed...not that good with words. =) Better late than never!
We had 2 irc meetings with Fardad during study break. We learnt what it means and how to update and commit on SVN.
oh and one important rule NEVER COMMIT SOMETHING THAT'S NOT BUILDABLE.
At this point we are in the process of committing our assigned classes(menubar and field for me).

My command line SVN doesn't work (not that it matters that much coz GUI works just fine). I checked PATH in my environmental variables and it's included. Anyone else having the same problem?

On a lighter note...Does anyone else find the SVN tortoise adorable?? I think I'll make a T-shirt out of it one day.

OOP344 Assignment progress 2

2009-10-11T19:57:00.000-07:00

With Jonathan's help I was able to pass all tests on VCC and LINUX (Thank you Jonathan!)
But now I'm having trouble compiling in borland.
I compiled with the command
bcc32 main.c ciol.c (I hope this is the right command)
But I got a whole bunch of "no prototype" warnings:
call to function "io_init" with no protype in function main
or
call to function "test 1" with no protype in function main

I've included the .h file in both main and ciol.c
Anyone has any idea what's going on?

OOP344 Assignment progress

2009-10-10T14:10:00.000-07:00

My program has successfully passed all tests except for 2:

Test 9.14:
Complaint about curpos. It says that curpos should be at 20, mine returned 19. But fieldlen of 20 is passed to io_edit. Shouldn't curpos be 1 less than fieldlen?
Anyone else having this problem?

Test 9.23:
Complaint about curpos and offset. It seems that curpos and offset should not be moved in this function. But IsTextEditor is set to false we should be able to move curpos and offset as long as the string returned is the orginal one and not the modified one.
Any thoughts on that?

oops posted the wrong io_display!

2009-09-27T21:49:00.000-07:00

Posted the old one I was playing around with...the current one is this:

for (io_move(row, col), len<=0 ? len=strlen(str) : len; len > 0; len--, *str++) {
*str ? io_putch(*str) : io_putch(' ');
}

Still missing one space though...

io_display in one line

2009-09-27T20:45:00.000-07:00

This does not fully work.
It's a success against cases where strlen(str) > len and len <= 0.
However when strlen(str) < len it fills up the remaining field with all but one space (eg. if str is "abc" and len is 6, it would only print "abc" plus 2 spaces). I've given up on it, at least for tonight.

for (io_move(row, col), len<=0 ? len=strlen(str) : len; len > 0; len--, *str++) {
len>0 && *str=='\0' ? io_putch(' ') : io_putch(*str);
}

My solution to OOP344 Challenge#1

2009-09-19T20:15:00.000-07:00

Here's my solution, I have a feeling that it's a little more complicated than it needs to be but it works...If anyone can help me make it simpler I'd appreciate it. =)

void GetInt(char *strint, int val){
/* sprintf(strint,"%d", val); */
int i, valcpy = val, n = 1, j;
for (i=0; valcpy>0; i++) {
valcpy /= 10;
n *= 10;
}
n /= 10;
for (i,j=0; i>0 ; i--,j++) {
valcpy = val / n;
strint[j] = valcpy + 48;
val -= valcpy * n;
n /= 10;
}
strint[j] = '\0';
}