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  • Can I use anything other than BIGINT as Primary Key data type in SQLite?

    - by weenet
    I was psyched about the possibility of using SQLite as a database solution during development so that I could focus on writing the code first and dynamically generating the db at runtime using NHibernate's ShemaExport functionality. However, I'm running into a few issues, not the least of which is that it seems that SQLite requires me to use Int64 for my primary keys (vs, say, Int32 or Guid). Is there any way around this?

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  • How to retain a row which is foreign key in another table and remove other duplicate rows?

    - by Mithril
    I have two table: A: id code 1 A1 2 A1 3 B1 4 B1 5 C1 6 C1 ===================== B: id Aid 1 1 2 4 (B doesn't contain the Aid which link to code C1) Let me explain the overall flow: I want to make each row in table A have different code(by delete duplicate),and I want to retain the Aid which I can find in table B.If Aid which not be saved in table B,I retain the id bigger one. so I can not just do something as below: DELETE FROM A WHERE id NOT IN (SELECT MAX(id) FROM A GROUP BY code, ) I can get each duplicate_code_groups by below sql statement: SELECT code FROM A GROUP BY code HAVING COUNT(*) > 1 Is there some code in sql like for (var ids in duplicate_code_groups){ for (var id in ids) { if (id in B){ return id } } return max(ids) } and put the return id into a idtable?? I just don't know how to write such code in sql. then I can do DELETE FROM A WHERE id NOT IN idtable

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  • In SQL Server 2000, how to delete the specified rows in a table that does not have a primary key?

    - by Yousui
    Hi, Let's say we have a table with some data in it. IF OBJECT_ID('dbo.table1') IS NOT NULL BEGIN DROP TABLE dbo.table1; END CREATE TABLE table1 ( DATA INT ); --------------------------------------------------------------------- -- Generating testing data --------------------------------------------------------------------- INSERT INTO dbo.table1(data) SELECT 100 UNION ALL SELECT 200 UNION ALL SELECT NULL UNION ALL SELECT 400 UNION ALL SELECT 400 UNION ALL SELECT 500 UNION ALL SELECT NULL; How to delete the 2nd, 5th, 6th records in the table? The order id defined by the following query. SELECT data FROM dbo.table1 ORDER BY data DESC; Note, this is in SQL Server 2000 environment. Thanks.

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  • .NET-MVC Modelbinder not binding because of primary key, all other fields are right. What's happenin

    - by ropstah
    I want to perform an Add object scenario in .NET using the modelbinder. Function AddObject() As ActionResult Return View() End Function <AcceptVerbs(HttpVerbs.Post)> _ Function AddObject(<Bind(Exclude:="ObjectId")> ByVal o As BLL.Object) As ActionResult o.Save() End Function However, I get an error: 'o.ObjectId' is not declared or the module containing it is not loaded in the debugging session. While inspecting the object, all other fields are set properly. I've tried all combinations regarding: with/without Html.Hidden("ObjectId") to with/without <Bind(Exclude:="ObjectId")> and even setting o.ObjectId to Nothing, all with the same results. What am I doing wrong?

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  • Printing the results in the original order

    - by Sam
    String[] numbers = new String[] {"3", "4", "s", "a", "c", "h", "i", "n", "t", "e", "n", "d", "u", "l", "k"}; Map<String, Integer> map = new HashMap<String, Integer>(); for (int i = 0; i < numbers.length; i++) { String key = numbers[i]; if (map.containsKey(key)) { int occurrence = map.get(key); occurrence++; map.put(key, occurrence); } else { map.put(key, 1); }// end of if else }// end of for loop Iterator<String> iterator = map.keySet().iterator(); while (iterator.hasNext()) { String key = iterator.next(); int occurrence = map.get(key); System.out.println(key + " occur " + occurrence + " time(s)."); } This program tries to count the number of occurrences of a string. When I execute it I am getting the answer, but the output is not in the original order, it is shuffled. How can I output the strings in the original order?

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  • which sql query is more efficient: select count(*) or select ... where key>value?

    - by davka
    I need to periodically update a local cache with new additions to some DB table. The table rows contain an auto-increment sequential number (SN) field. The cache keeps this number too, so basically I just need to fetch all rows with SN larger than the highest I already have. SELECT * FROM table where SN > <max_cached_SN> However, the majority of the attempts will bring no data (I just need to make sure that I have an absolutely up-to-date local copy). So I wander if this will be more efficient: count = SELECT count(*) from table; if (count > <cache_size>) // fetch new rows as above I suppose that selecting by an indexed numeric field is quite efficient, so I wander whether using count has benefit. On the other hand, this test/update will be done quite frequently and by many clients, so there is a motivation to optimize it.

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  • Where can I find a compact programming keyboard with logical key placement?

    - by Lefler
    I recently, at the order of my chiropractor, bought a laptop stand to elevate my screen. A result of this is that I need a standalone keyboard. Normal keyboards have numeric keypads on the right side, which moves my mouse further to the right... not an optimal position chiropractically speaking. I don't use the numeric keypad, but all the compact keyboards I can find use some random placement algorithm on the arrow, page up/down, and most importantly -- the insert,delete,home and end keys. Those misplaced keys are crippling my code entry. Does anyone know of a keyboard that is minus the keypad, but places those VERY IMPORTANT keys in a more standard position?

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  • Generate Delete Statement From Foreign Key Relationships in SQL 2008 ?

    - by Element
    Is it possible via script/tool to generate a delete statement based on the tables fk relations. i.e. I have the table: DelMe(ID) and there are 30 tables with fk references to its ID that I need to delete first, is there some tool/script that I can run that will generate the 30 delete statements based on the FK relations for me ? (btw I know about cascade delete on the relations, I can't use it in this existing db) I'm using Microsoft SQL Server 2008

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  • SQL - Query to display average as either "longer than" or "shorter than"

    - by user1840801
    Here are the tables I've created: CREATE TABLE Plane_new (Pnum char(3), Feature varchar2(20), Ptype varchar2(15), primary key (Pnum)); CREATE TABLE Employee_new (eid char(3), ename varchar(10), salary number(7,2), mid char(3), PRIMARY KEY (eid), FOREIGN KEY (mid) REFERENCES Employee_new); CREATE TABLE Pilot_new (eid char(3), Licence char(9), primary key (eid), foreign key (eid) references Employee_new on delete cascade); CREATE TABLE FlightI_new (Fnum char(4), Fdate date, Duration number(2), Pid char(3), Pnum char(3), primary key (Fnum), foreign key (Pid) references Pilot_new (eid), foreign key (Pnum) references Plane_new); And here is the query I must complete: For each flight, display its number, the name of the pilot who implemented the flight and the words ‘Longer than average’ if the flight duration was longer than average or the words ‘Shorter than average’ if the flight duration was shorter than or equal to the average. For the column holding the words ‘Longer than average’ or ‘Shorter than average’ make a header Length. Here is what I've come up with - with no luck! SELECT F.Fnum, E.ename, CASE Length WHEN F.Duration>(SELECT AVG(F.Duration) FROM FlightI_new F) THEN "Longer than average" WHEN F.Duration<=(SELECT AVG(F.Duration) FROM FlightI_new F) THEN 'Shorter than average' END FROM FlightI_new F LEFT OUTER JOIN Employee_new E ON F.Pid=E.eid GROUP BY F.Fnum, E.ename; Where am I going wrong?

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  • How can I sum array values by unique key?

    - by AndrewSpilak
    For example array ( product1_quantity => 5, product1_quantity => 1, product2_quantity => 3, product2_quantity => 7, product3_quantity => 2, ) with result: product1_quantity - 6, product2_quantity - 10, product3_quantity - 2 Thanx! sorry, guys stupid example, instead this really Array ( [0] = Array ( [product1] = 7 ) [1] = Array ( [product1] = 2 ) [2] = Array ( [product2] = 3 ) ) ?

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  • Problem with RewriteCond %{QUERY_STRING}, backreference not dispaying in final URL

    - by eb_Dev
    Hi, I have the following in my .htaccess file: RewriteCond %{QUERY_STRING} ^route\=product\/category\&path\=35\&page\=([0-9]+)$ RewriteRule ^index.php$ http://%{HTTP_HOST}/product/category/35/page_$1? [R=301,L] It's not behaving as expected though, when I enter the URL: http://mywebsite.com/index.php?route=product/category&path=35&page=2 It gets rewritten to: http://mywebsite.com/product/category/35/page_ Could someone tell me what I have done wrong please? Thanks, eb_dev

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  • Add collison detection to enemy sprites?

    - by xBroak
    i'd like to add the same collision detection used by the player sprite to the enemy sprites or 'creeps' ive added all the relevant code I can see yet collisons are still not being detected and handled, please find below the class, I have no idea what is wrong currently, the list of walls to collide with is 'wall_list' import pygame import pauseScreen as dm import re from pygame.sprite import Sprite from pygame import Rect, Color from random import randint, choice from vec2d import vec2d from simpleanimation import SimpleAnimation import displattxt black = (0,0,0) white = (255,255,255) blue = (0,0,255) green = (101,194,151) global currentEditTool currentEditTool = "Tree" global editMap editMap = False open('MapMaker.txt', 'w').close() def draw_background(screen, tile_img): screen.fill(black) img_rect = tile_img.get_rect() global rect rect = img_rect nrows = int(screen.get_height() / img_rect.height) + 1 ncols = int(screen.get_width() / img_rect.width) + 1 for y in range(nrows): for x in range(ncols): img_rect.topleft = (x * img_rect.width, y * img_rect.height) screen.blit(tile_img, img_rect) def changeTool(): if currentEditTool == "Tree": None elif currentEditTool == "Rock": None def pauseGame(): red = 255, 0, 0 green = 0,255, 0 blue = 0, 0,255 screen.fill(black) pygame.display.update() if editMap == False: choose = dm.dumbmenu(screen, [ 'Resume', 'Enable Map Editor', 'Quit Game'], 64,64,None,32,1.4,green,red) if choose == 0: print("hi") elif choose ==1: global editMap editMap = True elif choose ==2: print("bob") elif choose ==3: print("bob") elif choose ==4: print("bob") else: None else: choose = dm.dumbmenu(screen, [ 'Resume', 'Disable Map Editor', 'Quit Game'], 64,64,None,32,1.4,green,red) if choose == 0: print("Resume") elif choose ==1: print("Dis ME") global editMap editMap = False elif choose ==2: print("bob") elif choose ==3: print("bob") elif choose ==4: print("bob") else: None class Wall(pygame.sprite.Sprite): # Constructor function def __init__(self,x,y,width,height): pygame.sprite.Sprite.__init__(self) self.image = pygame.Surface([width, height]) self.image.fill(green) self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x class insertTree(pygame.sprite.Sprite): def __init__(self,x,y,width,height, typ): pygame.sprite.Sprite.__init__(self) self.image = pygame.image.load("images/map/tree.png").convert() self.image.set_colorkey(white) self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x class insertRock(pygame.sprite.Sprite): def __init__(self,x,y,width,height, typ): pygame.sprite.Sprite.__init__(self) self.image = pygame.image.load("images/map/rock.png").convert() self.image.set_colorkey(white) self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x class Creep(pygame.sprite.Sprite): """ A creep sprite that bounces off walls and changes its direction from time to time. """ change_x=0 change_y=0 def __init__( self, screen, creep_image, explosion_images, field, init_position, init_direction, speed): """ Create a new Creep. screen: The screen on which the creep lives (must be a pygame Surface object, such as pygame.display) creep_image: Image (surface) object for the creep explosion_images: A list of image objects for the explosion animation. field: A Rect specifying the 'playing field' boundaries. The Creep will bounce off the 'walls' of this field. init_position: A vec2d or a pair specifying the initial position of the creep on the screen. init_direction: A vec2d or a pair specifying the initial direction of the creep. Must have an angle that is a multiple of 45 degres. speed: Creep speed, in pixels/millisecond (px/ms) """ Sprite.__init__(self) self.screen = screen self.speed = speed self.field = field self.rect = creep_image.get_rect() # base_image holds the original image, positioned to # angle 0. # image will be rotated. # self.base_image = creep_image self.image = self.base_image self.explosion_images = explosion_images # A vector specifying the creep's position on the screen # self.pos = vec2d(init_position) # The direction is a normalized vector # self.direction = vec2d(init_direction).normalized() self.state = Creep.ALIVE self.health = 15 def is_alive(self): return self.state in (Creep.ALIVE, Creep.EXPLODING) def changespeed(self,x,y): self.change_x+=x self.change_y+=y def update(self, time_passed, walls): """ Update the creep. time_passed: The time passed (in ms) since the previous update. """ if self.state == Creep.ALIVE: # Maybe it's time to change the direction ? # self._change_direction(time_passed) # Make the creep point in the correct direction. # Since our direction vector is in screen coordinates # (i.e. right bottom is 1, 1), and rotate() rotates # counter-clockwise, the angle must be inverted to # work correctly. # self.image = pygame.transform.rotate( self.base_image, -self.direction.angle) # Compute and apply the displacement to the position # vector. The displacement is a vector, having the angle # of self.direction (which is normalized to not affect # the magnitude of the displacement) # displacement = vec2d( self.direction.x * self.speed * time_passed, self.direction.y * self.speed * time_passed) self.pos += displacement # When the image is rotated, its size is changed. # We must take the size into account for detecting # collisions with the walls. # self.image_w, self.image_h = self.image.get_size() bounds_rect = self.field.inflate( -self.image_w, -self.image_h) if self.pos.x < bounds_rect.left: self.pos.x = bounds_rect.left self.direction.x *= -1 elif self.pos.x > bounds_rect.right: self.pos.x = bounds_rect.right self.direction.x *= -1 elif self.pos.y < bounds_rect.top: self.pos.y = bounds_rect.top self.direction.y *= -1 elif self.pos.y > bounds_rect.bottom: self.pos.y = bounds_rect.bottom self.direction.y *= -1 # collision detection old_x=bounds_rect.left new_x=old_x+self.direction.x bounds_rect.left = new_x # hit a wall? collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes bounds_rect.left=old_x old_y=self.pos.y new_y=old_y+self.direction.y self.pos.y = new_y collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes self.pos.y=old_y elif self.state == Creep.EXPLODING: if self.explode_animation.active: self.explode_animation.update(time_passed) else: self.state = Creep.DEAD self.kill() elif self.state == Creep.DEAD: pass #------------------ PRIVATE PARTS ------------------# # States the creep can be in. # # ALIVE: The creep is roaming around the screen # EXPLODING: # The creep is now exploding, just a moment before dying. # DEAD: The creep is dead and inactive # (ALIVE, EXPLODING, DEAD) = range(3) _counter = 0 def _change_direction(self, time_passed): """ Turn by 45 degrees in a random direction once per 0.4 to 0.5 seconds. """ self._counter += time_passed if self._counter > randint(400, 500): self.direction.rotate(45 * randint(-1, 1)) self._counter = 0 def _point_is_inside(self, point): """ Is the point (given as a vec2d) inside our creep's body? """ img_point = point - vec2d( int(self.pos.x - self.image_w / 2), int(self.pos.y - self.image_h / 2)) try: pix = self.image.get_at(img_point) return pix[3] > 0 except IndexError: return False def _decrease_health(self, n): """ Decrease my health by n (or to 0, if it's currently less than n) """ self.health = max(0, self.health - n) if self.health == 0: self._explode() def _explode(self): """ Starts the explosion animation that ends the Creep's life. """ self.state = Creep.EXPLODING pos = ( self.pos.x - self.explosion_images[0].get_width() / 2, self.pos.y - self.explosion_images[0].get_height() / 2) self.explode_animation = SimpleAnimation( self.screen, pos, self.explosion_images, 100, 300) global remainingCreeps remainingCreeps-=1 if remainingCreeps == 0: print("all dead") def draw(self): """ Blit the creep onto the screen that was provided in the constructor. """ if self.state == Creep.ALIVE: # The creep image is placed at self.pos. To allow for # smooth movement even when the creep rotates and the # image size changes, its placement is always # centered. # self.draw_rect = self.image.get_rect().move( self.pos.x - self.image_w / 2, self.pos.y - self.image_h / 2) self.screen.blit(self.image, self.draw_rect) # The health bar is 15x4 px. # health_bar_x = self.pos.x - 7 health_bar_y = self.pos.y - self.image_h / 2 - 6 self.screen.fill( Color('red'), (health_bar_x, health_bar_y, 15, 4)) self.screen.fill( Color('green'), ( health_bar_x, health_bar_y, self.health, 4)) elif self.state == Creep.EXPLODING: self.explode_animation.draw() elif self.state == Creep.DEAD: pass def mouse_click_event(self, pos): """ The mouse was clicked in pos. """ if self._point_is_inside(vec2d(pos)): self._decrease_health(3) #begin new player class Player(pygame.sprite.Sprite): change_x=0 change_y=0 frame = 0 def __init__(self,x,y): pygame.sprite.Sprite.__init__(self) # LOAD PLATER IMAGES # Set height, width self.images = [] for i in range(1,17): img = pygame.image.load("images/player/" + str(i)+".png").convert() #player images img.set_colorkey(white) self.images.append(img) self.image = self.images[0] self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x self.health = 15 self.image_w, self.image_h = self.image.get_size() health_bar_x = self.rect.x - 7 health_bar_y = self.rect.y - self.image_h / 2 - 6 screen.fill( Color('red'), (health_bar_x, health_bar_y, 15, 4)) screen.fill( Color('green'), ( health_bar_x, health_bar_y, self.health, 4)) def changespeed(self,x,y): self.change_x+=x self.change_y+=y def _decrease_health(self, n): """ Decrease my health by n (or to 0, if it's currently less than n) """ self.health = max(0, self.health - n) if self.health == 0: self._explode() def update(self,walls): # collision detection old_x=self.rect.x new_x=old_x+self.change_x self.rect.x = new_x # hit a wall? collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes self.rect.x=old_x old_y=self.rect.y new_y=old_y+self.change_y self.rect.y = new_y collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes self.rect.y=old_y # right to left if self.change_x < 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 # Grab the image, divide by 4 # every 4 frames. self.image = self.images[self.frame//4] # Move left to right. # images 4...7 instead of 0...3. if self.change_x > 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 self.image = self.images[self.frame//4+4] if self.change_y > 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 self.image = self.images[self.frame//4+4+4] if self.change_y < 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 self.image = self.images[self.frame//4+4+4+4] score = 0 # initialize pyGame pygame.init() # 800x600 sized screen global screen screen = pygame.display.set_mode([800, 600]) screen.fill(black) #bg_tile_img = pygame.image.load('images/map/grass.png').convert_alpha() #draw_background(screen, bg_tile_img) #pygame.display.flip() # Set title pygame.display.set_caption('Test') #background = pygame.Surface(screen.get_size()) #background = background.convert() #background.fill(black) # Create the player player = Player( 50,50 ) player.rect.x=50 player.rect.y=50 movingsprites = pygame.sprite.RenderPlain() movingsprites.add(player) # Make the walls. (x_pos, y_pos, width, height) global wall_list wall_list=pygame.sprite.RenderPlain() wall=Wall(0,0,10,600) # left wall wall_list.add(wall) wall=Wall(10,0,790,10) # top wall wall_list.add(wall) #wall=Wall(10,200,100,10) # poke wall wall_list.add(wall) wall=Wall(790,0,10,600) #(x,y,thickness, height) wall_list.add(wall) wall=Wall(10,590,790,10) #(x,y,thickness, height) wall_list.add(wall) f = open('MapMaker.txt') num_lines = sum(1 for line in f) print(num_lines) lineCount = 0 with open("MapMaker.txt") as infile: for line in infile: f = open('MapMaker.txt') print(line) coords = line.split(',') #print(coords[0]) #print(coords[1]) #print(coords[2]) #print(coords[3]) #print(coords[4]) if "tree" in line: print("tree in") wall=insertTree(int(coords[0]),int(coords[1]), int(coords[2]),int(coords[3]),coords[4]) wall_list.add(wall) elif "rock" in line: print("rock in") wall=insertRock(int(coords[0]),int(coords[1]), int(coords[2]),int(coords[3]),coords[4] ) wall_list.add(wall) width = 20 height = 540 height = height - 48 for i in range(0,23): width = width + 32 name = insertTree(width,540,790,10,"tree") #wall_list.add(name) name = insertTree(width,height,690,10,"tree") #wall_list.add(name) CREEP_SPAWN_TIME = 200 # frames creep_spawn = CREEP_SPAWN_TIME clock = pygame.time.Clock() bg_tile_img = pygame.image.load('images/map/grass.png').convert() img_rect = bg_tile_img FIELD_RECT = Rect(50, 50, 700, 500) CREEP_FILENAMES = [ 'images/player/1.png', 'images/player/1.png', 'images/player/1.png'] N_CREEPS = 3 creep_images = [ pygame.image.load(filename).convert_alpha() for filename in CREEP_FILENAMES] explosion_img = pygame.image.load('images/map/tree.png').convert_alpha() explosion_images = [ explosion_img, pygame.transform.rotate(explosion_img, 90)] creeps = pygame.sprite.RenderPlain() done = False #bg_tile_img = pygame.image.load('images/map/grass.png').convert() #draw_background(screen, bg_tile_img) totalCreeps = 0 remainingCreeps = 3 while done == False: creep_images = pygame.image.load("images/player/1.png").convert() creep_images.set_colorkey(white) draw_background(screen, bg_tile_img) if len(creeps) != N_CREEPS: if totalCreeps < N_CREEPS: totalCreeps = totalCreeps + 1 print(totalCreeps) creeps.add( Creep( screen=screen, creep_image=creep_images, explosion_images=explosion_images, field=FIELD_RECT, init_position=( randint(FIELD_RECT.left, FIELD_RECT.right), randint(FIELD_RECT.top, FIELD_RECT.bottom)), init_direction=(choice([-1, 1]), choice([-1, 1])), speed=0.01)) for creep in creeps: creep.update(60,wall_list) creep.draw() for event in pygame.event.get(): if event.type == pygame.QUIT: done=True if event.type == pygame.KEYDOWN: if event.key == pygame.K_LEFT: player.changespeed(-2,0) creep.changespeed(-2,0) if event.key == pygame.K_RIGHT: player.changespeed(2,0) creep.changespeed(2,0) if event.key == pygame.K_UP: player.changespeed(0,-2) creep.changespeed(0,-2) if event.key == pygame.K_DOWN: player.changespeed(0,2) creep.changespeed(0,2) if event.key == pygame.K_ESCAPE: pauseGame() if event.key == pygame.K_1: global currentEditTool currentEditTool = "Tree" changeTool() if event.key == pygame.K_2: global currentEditTool currentEditTool = "Rock" changeTool() if event.type == pygame.KEYUP: if event.key == pygame.K_LEFT: player.changespeed(2,0) creep.changespeed(2,0) if event.key == pygame.K_RIGHT: player.changespeed(-2,0) creep.changespeed(-2,0) if event.key == pygame.K_UP: player.changespeed(0,2) creep.changespeed(0,2) if event.key == pygame.K_DOWN: player.changespeed(0,-2) creep.changespeed(0,-2) if event.type == pygame.MOUSEBUTTONDOWN and pygame.mouse.get_pressed()[0]: for creep in creeps: creep.mouse_click_event(pygame.mouse.get_pos()) if editMap == True: x,y = pygame.mouse.get_pos() if currentEditTool == "Tree": name = insertTree(x-10,y-25, 10 , 10, "tree") wall_list.add(name) wall_list.draw(screen) f = open('MapMaker.txt', "a+") image = pygame.image.load("images/map/tree.png").convert() screen.blit(image, (30,10)) pygame.display.flip() f.write(str(x) + "," + str(y) + ",790,10, tree\n") #f.write("wall=insertTree(" + str(x) + "," + str(y) + ",790,10)\nwall_list.add(wall)\n") elif currentEditTool == "Rock": name = insertRock(x-10,y-25, 10 , 10,"rock") wall_list.add(name) wall_list.draw(screen) f = open('MapMaker.txt', "a+") f.write(str(x) + "," + str(y) + ",790,10,rock\n") #f.write("wall=insertRock(" + str(x) + "," + str(y) + ",790,10)\nwall_list.add(wall)\n") else: None #pygame.display.flip() player.update(wall_list) movingsprites.draw(screen) wall_list.draw(screen) pygame.display.flip() clock.tick(60) pygame.quit()

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  • heimdal kerberos in openldap issue

    - by Brian
    I think I posted this on the wrong 'sister site', so here it is. I'm having a bit of trouble getting Kerberos (Heimdal version) to work nicely with OpenLDAP. The kerberos database is being stored in LDAP itself. The KDC uses SASL EXTERNAL authentication as root to access the container ou. I created the database in LDAP fine using kadmin -l, but it won't let me use kadmin without the -l flag: root@rds0:~# kadmin -l kadmin> list * krbtgt/REALM kadmin/changepw kadmin/admin changepw/kerberos kadmin/hprop WELLKNOWN/ANONYMOUS WELLKNOWN/org.h5l.fast-cookie@WELLKNOWN:ORG.H5L default brian.empson brian.empson/admin host/rds0.example.net ldap/rds0.example.net host/localhost kadmin> exit root@rds0:~# kadmin kadmin> list * brian.empson/admin@REALM's Password: <----- With right password kadmin: kadm5_get_principals: Key table entry not found kadmin> list * brian.empson/admin@REALM's Password: <------ With wrong password kadmin: kadm5_get_principals: Already tried ENC-TS-info, looping kadmin> I can get tickets without a problem: root@rds0:~# klist Credentials cache: FILE:/tmp/krb5cc_0 Principal: brian.empson@REALM Issued Expires Principal Nov 11 14:14:40 2012 Nov 12 00:14:37 2012 krbtgt/REALM@REALM Nov 11 14:40:35 2012 Nov 12 00:14:37 2012 ldap/rds0.example.net@REALM But I can't seem to change my own password without kadmin -l: root@rds0:~# kpasswd brian.empson@REALM's Password: <---- Right password New password: Verify password - New password: Auth error : Authentication failed root@rds0:~# kpasswd brian.empson@REALM's Password: <---- Wrong password kpasswd: krb5_get_init_creds: Already tried ENC-TS-info, looping kadmin's logs are not helpful at all: 2012-11-11T13:48:33 krb5_recvauth: Key table entry not found 2012-11-11T13:51:18 krb5_recvauth: Key table entry not found 2012-11-11T13:53:02 krb5_recvauth: Key table entry not found 2012-11-11T14:16:34 krb5_recvauth: Key table entry not found 2012-11-11T14:20:24 krb5_recvauth: Key table entry not found 2012-11-11T14:20:44 krb5_recvauth: Key table entry not found 2012-11-11T14:21:29 krb5_recvauth: Key table entry not found 2012-11-11T14:21:46 krb5_recvauth: Key table entry not found 2012-11-11T14:23:09 krb5_recvauth: Key table entry not found 2012-11-11T14:45:39 krb5_recvauth: Key table entry not found The KDC reports that both accounts succeed in authenticating: 2012-11-11T14:48:03 AS-REQ brian.empson@REALM from IPv4:192.168.72.10 for kadmin/changepw@REALM 2012-11-11T14:48:03 Client sent patypes: REQ-ENC-PA-REP 2012-11-11T14:48:03 Looking for PK-INIT(ietf) pa-data -- brian.empson@REALM 2012-11-11T14:48:03 Looking for PK-INIT(win2k) pa-data -- brian.empson@REALM 2012-11-11T14:48:03 Looking for ENC-TS pa-data -- brian.empson@REALM 2012-11-11T14:48:03 Need to use PA-ENC-TIMESTAMP/PA-PK-AS-REQ 2012-11-11T14:48:03 sending 294 bytes to IPv4:192.168.72.10 2012-11-11T14:48:03 AS-REQ brian.empson@REALM from IPv4:192.168.72.10 for kadmin/changepw@REALM 2012-11-11T14:48:03 Client sent patypes: ENC-TS, REQ-ENC-PA-REP 2012-11-11T14:48:03 Looking for PK-INIT(ietf) pa-data -- brian.empson@REALM 2012-11-11T14:48:03 Looking for PK-INIT(win2k) pa-data -- brian.empson@REALM 2012-11-11T14:48:03 Looking for ENC-TS pa-data -- brian.empson@REALM 2012-11-11T14:48:03 ENC-TS Pre-authentication succeeded -- brian.empson@REALM using aes256-cts-hmac-sha1-96 2012-11-11T14:48:03 ENC-TS pre-authentication succeeded -- brian.empson@REALM 2012-11-11T14:48:03 AS-REQ authtime: 2012-11-11T14:48:03 starttime: unset endtime: 2012-11-11T14:53:00 renew till: unset 2012-11-11T14:48:03 Client supported enctypes: aes256-cts-hmac-sha1-96, aes128-cts-hmac-sha1-96, des3-cbc-sha1, arcfour-hmac-md5, using aes256-cts-hmac-sha1-96/aes256-cts-hmac-sha1-96 2012-11-11T14:48:03 sending 704 bytes to IPv4:192.168.72.10 2012-11-11T14:45:39 AS-REQ brian.empson/admin@REALM from IPv4:192.168.72.10 for kadmin/admin@REALM 2012-11-11T14:45:39 Client sent patypes: REQ-ENC-PA-REP 2012-11-11T14:45:39 Looking for PK-INIT(ietf) pa-data -- brian.empson/admin@REALM 2012-11-11T14:45:39 Looking for PK-INIT(win2k) pa-data -- brian.empson/admin@REALM 2012-11-11T14:45:39 Looking for ENC-TS pa-data -- brian.empson/admin@REALM 2012-11-11T14:45:39 Need to use PA-ENC-TIMESTAMP/PA-PK-AS-REQ 2012-11-11T14:45:39 sending 303 bytes to IPv4:192.168.72.10 2012-11-11T14:45:39 AS-REQ brian.empson/admin@REALM from IPv4:192.168.72.10 for kadmin/admin@REALM 2012-11-11T14:45:39 Client sent patypes: ENC-TS, REQ-ENC-PA-REP 2012-11-11T14:45:39 Looking for PK-INIT(ietf) pa-data -- brian.empson/admin@REALM 2012-11-11T14:45:39 Looking for PK-INIT(win2k) pa-data -- brian.empson/admin@REALM 2012-11-11T14:45:39 Looking for ENC-TS pa-data -- brian.empson/admin@REALM 2012-11-11T14:45:39 ENC-TS Pre-authentication succeeded -- brian.empson/admin@REALM using aes256-cts-hmac-sha1-96 2012-11-11T14:45:39 ENC-TS pre-authentication succeeded -- brian.empson/admin@REALM 2012-11-11T14:45:39 AS-REQ authtime: 2012-11-11T14:45:39 starttime: unset endtime: 2012-11-11T15:45:39 renew till: unset 2012-11-11T14:45:39 Client supported enctypes: aes256-cts-hmac-sha1-96, aes128-cts-hmac-sha1-96, des3-cbc-sha1, arcfour-hmac-md5, using aes256-cts-hmac-sha1-96/aes256-cts-hmac-sha1-96 2012-11-11T14:45:39 sending 717 bytes to IPv4:192.168.72.10 I wish I had more detailed logging messages, running kadmind in debug mode seems to almost work but it just kicks me back to the shell when I type in the correct password. GSSAPI via LDAP doesn't work either, but I suspect it's because some parts of kerberos aren't working either: root@rds0:~# ldapsearch -Y GSSAPI -H ldaps:/// -b "o=mybase" o=mybase SASL/GSSAPI authentication started ldap_sasl_interactive_bind_s: Other (e.g., implementation specific) error (80) additional info: SASL(-1): generic failure: GSSAPI Error: Unspecified GSS failure. Minor code may provide more information () root@rds0:~# ldapsearch -Y EXTERNAL -H ldapi:/// -b "o=mybase" o=mybase SASL/EXTERNAL authentication started SASL username: gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth SASL SSF: 0 # extended LDIF <snip> Would anyone be able to point me in the right direction?

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  • Integrating Flickr with ASP.Net application

    - by sreejukg
    Flickr is the popular photo management and sharing application offered by yahoo. The services from flicker allow you to store and share photos and videos online. Flicker offers strong API support for almost all services they provide. Using this API, developers can integrate photos to their public website. Since 2005, developers have collaborated on top of Flickr's APIs to build fun, creative, and gorgeous experiences around photos that extend beyond Flickr. In this article I am going to demonstrate how easily you can bring the photos stored on flicker to your website. Let me explain the scenario this article is trying to address. I have a flicker account where I upload photos and share in many ways offered by Flickr. Now I have a public website, instead of re-upload the photos again to public website, I want to show this from Flickr. Also I need complete control over what photo to display. So I went and referred the Flickr documentation and there is API support ready to address my scenario (and more… ). FlickerAPI for ASP.Net To Integrate Flicker with ASP.Net applications, there is a library available in CodePlex. You can find it here http://flickrnet.codeplex.com/ Visit the URL and download the latest version. The download includes a Zip file, when you unzip you will get a number of dlls. Since I am going to use ASP.Net application, I need FlickrNet.dll. See the screenshot of all the dlls, and there is a help file available in the download (.chm) for your reference. Once you have the dll, you need to use Flickr API from your website. I assume you have a flicker account and you are familiar with Flicker services. Arrange your photos using Sets in Flickr In flicker, you can define sets and add your uploaded photos to sets. You can compare set to photo album. A set is a logical collection of photos, which is an excellent option for you to categorize your photos. Typically you will have a number of sets each set having few photos. You can write application that brings photos from sets to your website. For the purpose of this article I already created a set Flickr and added some photos to it. Once you logged in to Flickr, you can see the Sets under the Menu. In the Sets page, you will see all the sets you have created. As you notice, you can see certain sample images I have uploaded just to test the functionality. Though I wish I couldn’t create good photos so please bear with me. I have created 2 photo sets named Blue Album and Red Album. Click on the image for the set, will take you to the corresponding set page. In the set “Red Album” there are 4 photos and the set has a unique ID (highlighted in the URL). You can simply retrieve the photos with the set id from your application. In this article I am going to retrieve the images from Red album in my ASP.Net page. For that First I need to setup FlickrAPI for my usage. Configure Flickr API Key As I mentioned, we are going to use Flickr API to retrieve the photos stored in Flickr. In order to get access to Flickr API, you need an API key. To create an API key, navigate to the URL http://www.flickr.com/services/apps/create/ Click on Request an API key link, now you need to tell Flickr whether your application in commercial or non-commercial. I have selected a non-commercial key. Now you need to enter certain information about your application. Once you enter the details, Click on the submit button. Now Flickr will create the API key for your application. Generating non-commercial API key is very easy, in couple of steps the key will be generated and you can use the key in your application immediately. ASP.Net application for retrieving photos Now we need write an ASP.Net application that display pictures from Flickr. Create an empty web application (I named this as FlickerIntegration) and add a reference to FlickerNet.dll. Add a web form page to the application where you will retrieve and display photos(I have named this as Gallery.aspx). After doing all these, the solution explorer will look similar to following. I have used the below code in the Gallery.aspx page. The output for the above code is as follows. I am going to explain the code line by line here. First it is adding a reference to the FlickrNet namespace. using FlickrNet; Then create a Flickr object by using your API key. Flickr f = new Flickr("<yourAPIKey>"); Now when you retrieve photos, you can decide what all fields you need to retrieve from Flickr. Every photo in Flickr contains lots of information. Retrieving all will affect the performance. For the demonstration purpose, I have retrieved all the available fields as follows. PhotoSearchExtras.All But if you want to specify the fields you can use logical OR operator(|). For e.g. the following statement will retrieve owner name and date taken. PhotoSearchExtras extraInfo = PhotoSearchExtras.OwnerName | PhotoSearchExtras.DateTaken; Then retrieve all the photos from a photo set using PhotoSetsGetPhotos method. I have passed the PhotoSearchExtras object created earlier. PhotosetPhotoCollection photos = f.PhotosetsGetPhotos("72157629872940852", extraInfo); The PhotoSetsGetPhotos method will return a collection of Photo objects. You can just navigate through the collection using a foreach statement. foreach (Photo p in photos) {     //access each photo properties } Photo class have lot of properties that map with the properties from Flickr. The chm documentation comes along with the CodePlex download is a great asset for you to understand the fields. In the above code I just used the following p.LargeUrl – retrieves the large image url for the photo. p.ThumbnailUrl – retrieves the thumbnail url for the photo p.Title – retrieves the Title of the photo p.DateUploaded – retrieves the date of upload Visual Studio intellisense will give you all properties, so it is easy, you can just try with Visual Studio intellisense to find the right properties you are looking for. Most of hem are self-explanatory. So you can try retrieving the required properties. In the above code, I just pushed the photos to the page. In real time you can use the retrieved photos along with JQuery libraries to create animated photo galleries, slideshows etc. Configuration and Troubleshooting If you get access denied error while executing the code, you need to disable the caching in Flickr API. FlickrNet cache the photos to your local disk when retrieved. You can specify a cache folder where the application need write permission. You can specify the Cache folder in the code as follows. Flickr.CacheLocation = Server.MapPath("./FlickerCache/"); If the application doesn’t have have write permission to the cache folder, the application will throw access denied error. If you cannot give write permission to the cache folder, then you must disable the caching. You can do this from code as follows. Flickr.CacheDisabled = true; Disabling cache will have an impact on the performance. Take care! Also you can define the Flickr settings in web.config file.You can find the documentation here. http://flickrnet.codeplex.com/wikipage?title=ExampleConfigFile&ProjectName=flickrnet Flickr is a great place for storing and sharing photos. The API access allows developers to do seamless integration with the photos uploaded on Flickr.

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  • The Incremental Architect&acute;s Napkin &ndash; #3 &ndash; Make Evolvability inevitable

    - by Ralf Westphal
    Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/06/04/the-incremental-architectacutes-napkin-ndash-3-ndash-make-evolvability-inevitable.aspxThe easier something to measure the more likely it will be produced. Deviations between what is and what should be can be readily detected. That´s what automated acceptance tests are for. That´s what sprint reviews in Scrum are for. It´s no small wonder our software looks like it looks. It has all the traits whose conformance with requirements can easily be measured. And it´s lacking traits which cannot easily be measured. Evolvability (or Changeability) is such a trait. If an operation is correct, if an operation if fast enough, that can be checked very easily. But whether Evolvability is high or low, that cannot be checked by taking a measure or two. Evolvability might correlate with certain traits, e.g. number of lines of code (LOC) per function or Cyclomatic Complexity or test coverage. But there is no threshold value signalling “evolvability too low”; also Evolvability is hardly tangible for the customer. Nevertheless Evolvability is of great importance - at least in the long run. You can get away without much of it for a short time. Eventually, though, it´s needed like any other requirement. Or even more. Because without Evolvability no other requirement can be implemented. Evolvability is the foundation on which all else is build. Such fundamental importance is in stark contrast with its immeasurability. To compensate this, Evolvability must be put at the very center of software development. It must become the hub around everything else revolves. Since we cannot measure Evolvability, though, we cannot start watching it more. Instead we need to establish practices to keep it high (enough) at all times. Chefs have known that for long. That´s why everybody in a restaurant kitchen is constantly seeing after cleanliness. Hygiene is important as is to have clean tools at standardized locations. Only then the health of the patrons can be guaranteed and production efficiency is constantly high. Still a kitchen´s level of cleanliness is easier to measure than software Evolvability. That´s why important practices like reviews, pair programming, or TDD are not enough, I guess. What we need to keep Evolvability in focus and high is… to continually evolve. Change must not be something to avoid but too embrace. To me that means the whole change cycle from requirement analysis to delivery needs to be gone through more often. Scrum´s sprints of 4, 2 even 1 week are too long. Kanban´s flow of user stories across is too unreliable; it takes as long as it takes. Instead we should fix the cycle time at 2 days max. I call that Spinning. No increment must take longer than from this morning until tomorrow evening to finish. Then it should be acceptance checked by the customer (or his/her representative, e.g. a Product Owner). For me there are several resasons for such a fixed and short cycle time for each increment: Clear expectations Absolute estimates (“This will take X days to complete.”) are near impossible in software development as explained previously. Too much unplanned research and engineering work lurk in every feature. And then pervasive interruptions of work by peers and management. However, the smaller the scope the better our absolute estimates become. That´s because we understand better what really are the requirements and what the solution should look like. But maybe more importantly the shorter the timespan the more we can control how we use our time. So much can happen over the course of a week and longer timespans. But if push comes to shove I can block out all distractions and interruptions for a day or possibly two. That´s why I believe we can give rough absolute estimates on 3 levels: Noon Tonight Tomorrow Think of a meeting with a Product Owner at 8:30 in the morning. If she asks you, how long it will take you to implement a user story or bug fix, you can say, “It´ll be fixed by noon.”, or you can say, “I can manage to implement it until tonight before I leave.”, or you can say, “You´ll get it by tomorrow night at latest.” Yes, I believe all else would be naive. If you´re not confident to get something done by tomorrow night (some 34h from now) you just cannot reliably commit to any timeframe. That means you should not promise anything, you should not even start working on the issue. So when estimating use these four categories: Noon, Tonight, Tomorrow, NoClue - with NoClue meaning the requirement needs to be broken down further so each aspect can be assigned to one of the first three categories. If you like absolute estimates, here you go. But don´t do deep estimates. Don´t estimate dozens of issues; don´t think ahead (“Issue A is a Tonight, then B will be a Tomorrow, after that it´s C as a Noon, finally D is a Tonight - that´s what I´ll do this week.”). Just estimate so Work-in-Progress (WIP) is 1 for everybody - plus a small number of buffer issues. To be blunt: Yes, this makes promises impossible as to what a team will deliver in terms of scope at a certain date in the future. But it will give a Product Owner a clear picture of what to pull for acceptance feedback tonight and tomorrow. Trust through reliability Our trade is lacking trust. Customers don´t trust software companies/departments much. Managers don´t trust developers much. I find that perfectly understandable in the light of what we´re trying to accomplish: delivering software in the face of uncertainty by means of material good production. Customers as well as managers still expect software development to be close to production of houses or cars. But that´s a fundamental misunderstanding. Software development ist development. It´s basically research. As software developers we´re constantly executing experiments to find out what really provides value to users. We don´t know what they need, we just have mediated hypothesises. That´s why we cannot reliably deliver on preposterous demands. So trust is out of the window in no time. If we switch to delivering in short cycles, though, we can regain trust. Because estimates - explicit or implicit - up to 32 hours at most can be satisfied. I´d say: reliability over scope. It´s more important to reliably deliver what was promised then to cover a lot of requirement area. So when in doubt promise less - but deliver without delay. Deliver on scope (Functionality and Quality); but also deliver on Evolvability, i.e. on inner quality according to accepted principles. Always. Trust will be the reward. Less complexity of communication will follow. More goodwill buffer will follow. So don´t wait for some Kanban board to show you, that flow can be improved by scheduling smaller stories. You don´t need to learn that the hard way. Just start with small batch sizes of three different sizes. Fast feedback What has been finished can be checked for acceptance. Why wait for a sprint of several weeks to end? Why let the mental model of the issue and its solution dissipate? If you get final feedback after one or two weeks, you hardly remember what you did and why you did it. Resoning becomes hard. But more importantly youo probably are not in the mood anymore to go back to something you deemed done a long time ago. It´s boring, it´s frustrating to open up that mental box again. Learning is harder the longer it takes from event to feedback. Effort can be wasted between event (finishing an issue) and feedback, because other work might go in the wrong direction based on false premises. Checking finished issues for acceptance is the most important task of a Product Owner. It´s even more important than planning new issues. Because as long as work started is not released (accepted) it´s potential waste. So before starting new work better make sure work already done has value. By putting the emphasis on acceptance rather than planning true pull is established. As long as planning and starting work is more important, it´s a push process. Accept a Noon issue on the same day before leaving. Accept a Tonight issue before leaving today or first thing tomorrow morning. Accept a Tomorrow issue tomorrow night before leaving or early the day after tomorrow. After acceptance the developer(s) can start working on the next issue. Flexibility As if reliability/trust and fast feedback for less waste weren´t enough economic incentive, there is flexibility. After each issue the Product Owner can change course. If on Monday morning feature slices A, B, C, D, E were important and A, B, C were scheduled for acceptance by Monday evening and Tuesday evening, the Product Owner can change her mind at any time. Maybe after A got accepted she asks for continuation with D. But maybe, just maybe, she has gotten a completely different idea by then. Maybe she wants work to continue on F. And after B it´s neither D nor E, but G. And after G it´s D. With Spinning every 32 hours at latest priorities can be changed. And nothing is lost. Because what got accepted is of value. It provides an incremental value to the customer/user. Or it provides internal value to the Product Owner as increased knowledge/decreased uncertainty. I find such reactivity over commitment economically very benefical. Why commit a team to some workload for several weeks? It´s unnecessary at beast, and inflexible and wasteful at worst. If we cannot promise delivery of a certain scope on a certain date - which is what customers/management usually want -, we can at least provide them with unpredecented flexibility in the face of high uncertainty. Where the path is not clear, cannot be clear, make small steps so you´re able to change your course at any time. Premature completion Customers/management are used to premeditating budgets. They want to know exactly how much to pay for a certain amount of requirements. That´s understandable. But it does not match with the nature of software development. We should know that by now. Maybe there´s somewhere in the world some team who can consistently deliver on scope, quality, and time, and budget. Great! Congratulations! I, however, haven´t seen such a team yet. Which does not mean it´s impossible, but I think it´s nothing I can recommend to strive for. Rather I´d say: Don´t try this at home. It might hurt you one way or the other. However, what we can do, is allow customers/management stop work on features at any moment. With spinning every 32 hours a feature can be declared as finished - even though it might not be completed according to initial definition. I think, progress over completion is an important offer software development can make. Why think in terms of completion beyond a promise for the next 32 hours? Isn´t it more important to constantly move forward? Step by step. We´re not running sprints, we´re not running marathons, not even ultra-marathons. We´re in the sport of running forever. That makes it futile to stare at the finishing line. The very concept of a burn-down chart is misleading (in most cases). Whoever can only think in terms of completed requirements shuts out the chance for saving money. The requirements for a features mostly are uncertain. So how does a Product Owner know in the first place, how much is needed. Maybe more than specified is needed - which gets uncovered step by step with each finished increment. Maybe less than specified is needed. After each 4–32 hour increment the Product Owner can do an experient (or invite users to an experiment) if a particular trait of the software system is already good enough. And if so, she can switch the attention to a different aspect. In the end, requirements A, B, C then could be finished just 70%, 80%, and 50%. What the heck? It´s good enough - for now. 33% money saved. Wouldn´t that be splendid? Isn´t that a stunning argument for any budget-sensitive customer? You can save money and still get what you need? Pull on practices So far, in addition to more trust, more flexibility, less money spent, Spinning led to “doing less” which also means less code which of course means higher Evolvability per se. Last but not least, though, I think Spinning´s short acceptance cycles have one more effect. They excert pull-power on all sorts of practices known for increasing Evolvability. If, for example, you believe high automated test coverage helps Evolvability by lowering the fear of inadverted damage to a code base, why isn´t 90% of the developer community practicing automated tests consistently? I think, the answer is simple: Because they can do without. Somehow they manage to do enough manual checks before their rare releases/acceptance checks to ensure good enough correctness - at least in the short term. The same goes for other practices like component orientation, continuous build/integration, code reviews etc. None of that is compelling, urgent, imperative. Something else always seems more important. So Evolvability principles and practices fall through the cracks most of the time - until a project hits a wall. Then everybody becomes desperate; but by then (re)gaining Evolvability has become as very, very difficult and tedious undertaking. Sometimes up to the point where the existence of a project/company is in danger. With Spinning that´s different. If you´re practicing Spinning you cannot avoid all those practices. With Spinning you very quickly realize you cannot deliver reliably even on your 32 hour promises. Spinning thus is pulling on developers to adopt principles and practices for Evolvability. They will start actively looking for ways to keep their delivery rate high. And if not, management will soon tell them to do that. Because first the Product Owner then management will notice an increasing difficulty to deliver value within 32 hours. There, finally there emerges a way to measure Evolvability: The more frequent developers tell the Product Owner there is no way to deliver anything worth of feedback until tomorrow night, the poorer Evolvability is. Don´t count the “WTF!”, count the “No way!” utterances. In closing For sustainable software development we need to put Evolvability first. Functionality and Quality must not rule software development but be implemented within a framework ensuring (enough) Evolvability. Since Evolvability cannot be measured easily, I think we need to put software development “under pressure”. Software needs to be changed more often, in smaller increments. Each increment being relevant to the customer/user in some way. That does not mean each increment is worthy of shipment. It´s sufficient to gain further insight from it. Increments primarily serve the reduction of uncertainty, not sales. Sales even needs to be decoupled from this incremental progress. No more promises to sales. No more delivery au point. Rather sales should look at a stream of accepted increments (or incremental releases) and scoup from that whatever they find valuable. Sales and marketing need to realize they should work on what´s there, not what might be possible in the future. But I digress… In my view a Spinning cycle - which is not easy to reach, which requires practice - is the core practice to compensate the immeasurability of Evolvability. From start to finish of each issue in 32 hours max - that´s the challenge we need to accept if we´re serious increasing Evolvability. Fortunately higher Evolvability is not the only outcome of Spinning. Customer/management will like the increased flexibility and “getting more bang for the buck”.

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  • DocumentDB - Another Azure NoSQL Storage Service

    - by Shaun
    Originally posted on: http://geekswithblogs.net/shaunxu/archive/2014/08/25/documentdb---another-azure-nosql-storage-service.aspxMicrosoft just released a bunch of new features for Azure on 22nd and one of them I was interested in most is DocumentDB, a document NoSQL database service on the cloud.   Quick Look at DocumentDB We can try DocumentDB from the new azure preview portal. Just click the NEW button and select the item named DocumentDB to create a new account. Specify the name of the DocumentDB, which will be the endpoint we are going to use to connect later. Select the capacity unit, resource group and subscription. In resource group section we can select which region our DocumentDB will be located. Same as other azure services select the same location with your consumers of the DocumentDB, for example the website, web services, etc.. After several minutes the DocumentDB will be ready. Click the KEYS button we can find the URI and primary key, which will be used when connecting. Now let's open Visual Studio and try to use the DocumentDB we had just created. Create a new console application and install the DocumentDB .NET client library from NuGet with the keyword "DocumentDB". You need to select "Include Prerelase" in NuGet Package Manager window since this library was not yet released. Next we will create a new database and document collection under our DocumentDB account. The code below created an instance of DocumentClient with the URI and primary key we just copied from azure portal, and create a database and collection. And it also prints the document and collection link string which will be used later to insert and query documents. 1: static void Main(string[] args) 2: { 3: var endpoint = new Uri("https://shx.documents.azure.com:443/"); 4: var key = "LU2NoyS2fH0131TGxtBE4DW/CjHQBzAaUx/mbuJ1X77C4FWUG129wWk2oyS2odgkFO2Xdif9/ZddintQicF+lA=="; 5:  6: var client = new DocumentClient(endpoint, key); 7: Run(client).Wait(); 8:  9: Console.WriteLine("done"); 10: Console.ReadKey(); 11: } 12:  13: static async Task Run(DocumentClient client) 14: { 15:  16: var database = new Database() { Id = "testdb" }; 17: database = await client.CreateDatabaseAsync(database); 18: Console.WriteLine("database link = {0}", database.SelfLink); 19:  20: var collection = new DocumentCollection() { Id = "testcol" }; 21: collection = await client.CreateDocumentCollectionAsync(database.SelfLink, collection); 22: Console.WriteLine("collection link = {0}", collection.SelfLink); 23: } Below is the result from the console window. We need to copy the collection link string for future usage. Now if we back to the portal we will find a database was listed with the name we specified in the code. Next we will insert a document into the database and collection we had just created. In the code below we pasted the collection link which copied in previous step, create a dynamic object with several properties defined. As you can see we can add some normal properties contains string, integer, we can also add complex property for example an array, a dictionary and an object reference, unless they can be serialized to JSON. 1: static void Main(string[] args) 2: { 3: var endpoint = new Uri("https://shx.documents.azure.com:443/"); 4: var key = "LU2NoyS2fH0131TGxtBE4DW/CjHQBzAaUx/mbuJ1X77C4FWUG129wWk2oyS2odgkFO2Xdif9/ZddintQicF+lA=="; 5:  6: var client = new DocumentClient(endpoint, key); 7:  8: // collection link pasted from the result in previous demo 9: var collectionLink = "dbs/AAk3AA==/colls/AAk3AP6oFgA=/"; 10:  11: // document we are going to insert to database 12: dynamic doc = new ExpandoObject(); 13: doc.firstName = "Shaun"; 14: doc.lastName = "Xu"; 15: doc.roles = new string[] { "developer", "trainer", "presenter", "father" }; 16:  17: // insert the docuemnt 18: InsertADoc(client, collectionLink, doc).Wait(); 19:  20: Console.WriteLine("done"); 21: Console.ReadKey(); 22: } the insert code will be very simple as below, just provide the collection link and the object we are going to insert. 1: static async Task InsertADoc(DocumentClient client, string collectionLink, dynamic doc) 2: { 3: var document = await client.CreateDocumentAsync(collectionLink, doc); 4: Console.WriteLine(await JsonConvert.SerializeObjectAsync(document, Formatting.Indented)); 5: } Below is the result after the object had been inserted. Finally we will query the document from the database and collection. Similar to the insert code, we just need to specify the collection link so that the .NET SDK will help us to retrieve all documents in it. 1: static void Main(string[] args) 2: { 3: var endpoint = new Uri("https://shx.documents.azure.com:443/"); 4: var key = "LU2NoyS2fH0131TGxtBE4DW/CjHQBzAaUx/mbuJ1X77C4FWUG129wWk2oyS2odgkFO2Xdif9/ZddintQicF+lA=="; 5:  6: var client = new DocumentClient(endpoint, key); 7:  8: var collectionLink = "dbs/AAk3AA==/colls/AAk3AP6oFgA=/"; 9:  10: SelectDocs(client, collectionLink); 11:  12: Console.WriteLine("done"); 13: Console.ReadKey(); 14: } 15:  16: static void SelectDocs(DocumentClient client, string collectionLink) 17: { 18: var docs = client.CreateDocumentQuery(collectionLink + "docs/").ToList(); 19: foreach(var doc in docs) 20: { 21: Console.WriteLine(doc); 22: } 23: } Since there's only one document in my collection below is the result when I executed the code. As you can see all properties, includes the array was retrieve at the same time. DocumentDB also attached some properties we didn't specified such as "_rid", "_ts", "_self" etc., which is controlled by the service.   DocumentDB Benefit DocumentDB is a document NoSQL database service. Different from the traditional database, document database is truly schema-free. In a short nut, you can save anything in the same database and collection if it could be serialized to JSON. We you query the document database, all sub documents will be retrieved at the same time. This means you don't need to join other tables when using a traditional database. Document database is very useful when we build some high performance system with hierarchical data structure. For example, assuming we need to build a blog system, there will be many blog posts and each of them contains the content and comments. The comment can be commented as well. If we were using traditional database, let's say SQL Server, the database schema might be defined as below. When we need to display a post we need to load the post content from the Posts table, as well as the comments from the Comments table. We also need to build the comment tree based on the CommentID field. But if were using DocumentDB, what we need to do is to save the post as a document with a list contains all comments. Under a comment all sub comments will be a list in it. When we display this post we just need to to query the post document, the content and all comments will be loaded in proper structure. 1: { 2: "id": "xxxxx-xxxxx-xxxxx-xxxxx", 3: "title": "xxxxx", 4: "content": "xxxxx, xxxxxxxxx. xxxxxx, xx, xxxx.", 5: "postedOn": "08/25/2014 13:55", 6: "comments": 7: [ 8: { 9: "id": "xxxxx-xxxxx-xxxxx-xxxxx", 10: "content": "xxxxx, xxxxxxxxx. xxxxxx, xx, xxxx.", 11: "commentedOn": "08/25/2014 14:00", 12: "commentedBy": "xxx" 13: }, 14: { 15: "id": "xxxxx-xxxxx-xxxxx-xxxxx", 16: "content": "xxxxx, xxxxxxxxx. xxxxxx, xx, xxxx.", 17: "commentedOn": "08/25/2014 14:10", 18: "commentedBy": "xxx", 19: "comments": 20: [ 21: { 22: "id": "xxxxx-xxxxx-xxxxx-xxxxx", 23: "content": "xxxxx, xxxxxxxxx. xxxxxx, xx, xxxx.", 24: "commentedOn": "08/25/2014 14:18", 25: "commentedBy": "xxx", 26: "comments": 27: [ 28: { 29: "id": "xxxxx-xxxxx-xxxxx-xxxxx", 30: "content": "xxxxx, xxxxxxxxx. xxxxxx, xx, xxxx.", 31: "commentedOn": "08/25/2014 18:22", 32: "commentedBy": "xxx", 33: } 34: ] 35: }, 36: { 37: "id": "xxxxx-xxxxx-xxxxx-xxxxx", 38: "content": "xxxxx, xxxxxxxxx. xxxxxx, xx, xxxx.", 39: "commentedOn": "08/25/2014 15:02", 40: "commentedBy": "xxx", 41: } 42: ] 43: }, 44: { 45: "id": "xxxxx-xxxxx-xxxxx-xxxxx", 46: "content": "xxxxx, xxxxxxxxx. xxxxxx, xx, xxxx.", 47: "commentedOn": "08/25/2014 14:30", 48: "commentedBy": "xxx" 49: } 50: ] 51: }   DocumentDB vs. Table Storage DocumentDB and Table Storage are all NoSQL service in Microsoft Azure. One common question is "when we should use DocumentDB rather than Table Storage". Here are some ideas from me and some MVPs. First of all, they are different kind of NoSQL database. DocumentDB is a document database while table storage is a key-value database. Second, table storage is cheaper. DocumentDB supports scale out from one capacity unit to 5 in preview period and each capacity unit provides 10GB local SSD storage. The price is $0.73/day includes 50% discount. For storage service the highest price is $0.061/GB, which is almost 10% of DocumentDB. Third, table storage provides local-replication, geo-replication, read access geo-replication while DocumentDB doesn't support. Fourth, there is local emulator for table storage but none for DocumentDB. We have to connect to the DocumentDB on cloud when developing locally. But, DocumentDB supports some cool features that table storage doesn't have. It supports store procedure, trigger and user-defined-function. It supports rich indexing while table storage only supports indexing against partition key and row key. It supports transaction, table storage supports as well but restricted with Entity Group Transaction scope. And the last, table storage is GA but DocumentDB is still in preview.   Summary In this post I have a quick demonstration and introduction about the new DocumentDB service in Azure. It's very easy to interact through .NET and it also support REST API, Node.js SDK and Python SDK. Then I explained the concept and benefit of  using document database, then compared with table storage.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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  • SQL SERVER – Weekly Series – Memory Lane – #052

    - by Pinal Dave
    Let us continue with the final episode of the Memory Lane Series. Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Set Server Level FILLFACTOR Using T-SQL Script Specifies a percentage that indicates how full the Database Engine should make the leaf level of each index page during index creation or alteration. fillfactor must be an integer value from 1 to 100. The default is 0. Limitation of Online Index Rebuld Operation Online operation means when online operations are happening in the database are in normal operational condition, the processes which are participating in online operations does not require exclusive access to the database. Get Permissions of My Username / Userlogin on Server / Database A few days ago, I was invited to one of the largest database company. I was asked to review database schema and propose changes to it. There was special username or user logic was created for me, so I can review their database. I was very much interested to know what kind of permissions I was assigned per server level and database level. I did not feel like asking Sr. DBA the question about permissions. Simple Example of WHILE Loop With CONTINUE and BREAK Keywords This question is one of those questions which is very simple and most of the users get it correct, however few users find it confusing for the first time. I have tried to explain the usage of simple WHILE loop in the first example. BREAK keyword will exit the stop the while loop and control is moved to the next statement after the while loop. CONTINUE keyword skips all the statement after its execution and control is sent to the first statement of while loop. Forced Parameterization and Simple Parameterization – T-SQL and SSMS When the PARAMETERIZATION option is set to FORCED, any literal value that appears in a SELECT, INSERT, UPDATE or DELETE statement is converted to a parameter during query compilation. When the PARAMETERIZATION database option is SET to SIMPLE, the SQL Server query optimizer may choose to parameterize the queries. 2008 Transaction and Local Variables – Swap Variables – Update All At Once Concept Summary : Transaction have no effect over memory variables. When UPDATE statement is applied over any table (physical or memory) all the updates are applied at one time together when the statement is committed. First of all I suggest that you read the article listed above about the effect of transaction on local variant. As seen there local variables are independent of any transaction effect. Simulate INNER JOIN using LEFT JOIN statement – Performance Analysis Just a day ago, while I was working with JOINs I find one interesting observation, which has prompted me to create following example. Before we continue further let me make very clear that INNER JOIN should be used where it cannot be used and simulating INNER JOIN using any other JOINs will degrade the performance. If there are scopes to convert any OUTER JOIN to INNER JOIN it should be done with priority. 2009 Introduction to Business Intelligence – Important Terms & Definitions Business intelligence (BI) is a broad category of application programs and technologies for gathering, storing, analyzing, and providing access to data from various data sources, thus providing enterprise users with reliable and timely information and analysis for improved decision making. Difference Between Candidate Keys and Primary Key Candidate Key – A Candidate Key can be any column or a combination of columns that can qualify as unique key in database. There can be multiple Candidate Keys in one table. Each Candidate Key can qualify as Primary Key. Primary Key – A Primary Key is a column or a combination of columns that uniquely identify a record. Only one Candidate Key can be Primary Key. 2010 Taking Multiple Backup of Database in Single Command – Mirrored Database Backup I recently had a very interesting experience. In one of my recent consultancy works, I was told by our client that they are going to take the backup of the database and will also a copy of it at the same time. I expressed that it was surely possible if they were going to use a mirror command. In addition, they told me that whenever they take two copies of the database, the size of the database, is always reduced. Now this was something not clear to me, I said it was not possible and so I asked them to show me the script. Corrupted Backup File and Unsuccessful Restore The CTO, who was also present at the location, got very upset with this situation. He then asked when the last successful restore test was done. As expected, the answer was NEVER.There were no successful restore tests done before. During that time, I was present and I could clearly see the stress, confusion, carelessness and anger around me. I did not appreciate the feeling and I was pretty sure that no one in there wanted the atmosphere like me. 2011 TRACEWRITE – Wait Type – Wait Related to Buffer and Resolution SQL Trace is a SQL Server database engine technology which monitors specific events generated when various actions occur in the database engine. When any event is fired it goes through various stages as well various routes. One of the routes is Trace I/O Provider, which sends data to its final destination either as a file or rowset. DATEDIFF – Accuracy of Various Dateparts If you want to have accuracy in seconds, you need to use a different approach. In the first example, the accurate method is to find the number of seconds first and then divide it by 60 to convert it in minutes. Dedicated Access Control for SQL Server Express Edition http://www.youtube.com/watch?v=1k00z82u4OI Book Signing at SQLPASS 2012 Who I Am And How I Got Here – True Story as Blog Post If there was a shortcut to success – I want to know. I learnt SQL Server hard way and I am still learning. There are so many things, I have to learn. There is not enough time to learn everything which we want to learn. I am constantly working on it every day. I welcome you to join my journey as well. Please join me in my journey to learn SQL Server – more the merrier. Vacation, Travel and Study – A New Concept Even those who have advanced degrees and went to college for years, or even decades, find studying hard.  There is a difference between studying for a career and studying for a certification.  At least to get a degree there is a variety of subjects, with labs, exams, and practice problems to make things more interesting. Order By Numeric Values Formatted as String We have a table which has a column containing alphanumeric data. The data always has first as an integer and later part as a string. The business need is to order the data based on the first part of the alphanumeric data which is an integer. Now the problem is that no matter how we use ORDER BY the result is not produced as expected. Let us understand this with an example. Resolving SQL Server Connection Errors – SQL in Sixty Seconds #030 – Video One of the most famous errors related to SQL Server is about connecting to SQL Server itself. Here is how it goes, most of the time developers have worked with SQL Server and knows pretty much every error which they face during development language. However, hardly they install fresh SQL Server. As the installation of the SQL Server is a rare occasion unless you are a DBA who is responsible for such an instance – the error faced during installations are pretty rare as well. http://www.youtube.com/watch?v=1k00z82u4OI Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • how to do event checks for loops?

    - by yao jiang
    I am having some trouble getting the logic down for this. Currently, I have an app that animates the astar pathfinding algorithm. On start of the app, the ui will show the following: User can press "space" to randomly choose start/end coords, then the app will animate it. Or, user can choose the start/end by left-click/right-click. During the animation, the user can also left-click to generate blocks, or right-click to choose a new destiantion. Where I am stuck at is how to handle the events while the app is animating. Right now, I am checking events in the main loop, then when the app is animating, I do event checks again. While it works fine, I feel that I am probably doing it wrong. What is the proper way of setting up the main loop that will handle the events while the app is animating? In main loop, the app start animating once user choose start/end. In my draw function, I am putting another event checker in there. def clear(rows): for r in range(rows): for c in range(rows): if r%3 == 1 and c%3 == 1: color = brown; grid[r][c] = 1; buildCoor.append(r); buildCoor.append(c); else: color = white; grid[r][c] = 0; pick_image(screen, color, width*c, height*r); pygame.display.flip(); os.system('cls'); # draw out the grid def draw(start, end, grid, route_coord): # draw the end coords color = red; pick_image(screen, color, width*end[1],height*end[0]); pygame.display.flip(); # then draw the rest of the route for i in range(len(route_coord)): # pausing because we want animation time.sleep(speed); # get the x/y coords x,y = route_coord[i]; event_on = False; if grid[x][y] == 2: color = green; elif grid[x][y] == 3: color = blue; for event in pygame.event.get(): if event.type == pygame.MOUSEBUTTONDOWN: if event.button == 3: print "destination change detected, rerouting"; # get mouse position, px coords pos = pygame.mouse.get_pos(); # get grid coord c = pos[0] // width; r = pos[1] // height; grid[r][c] = 4; end = [r, c]; elif event.button == 1: print "user generated event"; pos = pygame.mouse.get_pos(); # get grid coord c = pos[0] // width; r = pos[1] // height; # mark it as a block for now grid[r][c] = 1; event_on = True; if check_events([x,y]) or event_on: # there is an event # mark it as a block for now grid[y][x] = 1; pick_image(screen, event_x, width*y, height*x); pygame.display.flip(); # then find a new route new_start = route_coord[i-1]; marked_grid, route_coord = find_route(new_start, end, grid); draw(new_start, end, grid, route_coord); return; # just end draw here so it wont throw the "index out of range" error elif grid[x][y] == 4: color = red; pick_image(screen, color, width*y, height*x); pygame.display.flip(); # clear route coord list, otherwise itll just add more unwanted coords route_coord_list[:] = []; clear(rows); # main loop while not done: # check the events for event in pygame.event.get(): # mouse events if event.type == pygame.MOUSEBUTTONDOWN: # get mouse position, px coords pos = pygame.mouse.get_pos(); # get grid coord c = pos[0] // width; r = pos[1] // height; # find which button pressed, highlight grid accordingly if event.button == 1: # left click, start coords if grid[r][c] == 2: grid[r][c] = 0; color = white; elif grid[r][c] == 0 or grid[r][c] == 4: grid[r][c] = 2; start = [r,c]; color = green; else: grid[r][c] = 1; color = brown; elif event.button == 3: # right click, end coords if grid[r][c] == 4: grid[r][c] = 0; color = white; elif grid[r][c] == 0 or grid[r][c] == 2: grid[r][c] = 4; end = [r,c]; color = red; else: grid[r][c] = 1; color = brown; pick_image(screen, color, width*c, height*r); # keyboard events elif event.type == pygame.KEYDOWN: clear(rows); # one way to quit program if event.key == pygame.K_ESCAPE: print "program will now exit."; done = True; # space key for random start/end elif event.key == pygame.K_SPACE: # first clear the ui clear(rows); # now choose random start/end coords buildLoc = zip(buildCoor,buildCoor[1:])[::2]; #print buildLoc; (start_x, start_y, end_x, end_y) = pick_point(); while (start_x, start_y) in buildLoc or (end_x, end_y) in buildLoc: (start_x, start_y, end_x, end_y) = pick_point(); clear(rows); print "chosen random start/end coords: ", (start_x, start_y, end_x, end_y); if (start_x, start_y) in buildLoc or (end_x, end_y) in buildLoc: print "error"; # draw the route marked_grid, route_coord = find_route([start_x,start_y],[end_x,end_y], grid); draw([start_x, start_y], [end_x, end_y], marked_grid, route_coord); # return key for user defined start/end elif event.key == pygame.K_RETURN: # first clear the ui clear(rows); # get the user defined start/end print "user defined start/end are: ", (start[0], start[1], end[0], end[1]); grid[start[0]][start[1]] = 1; grid[end[0]][end[1]] = 2; # draw the route marked_grid, route_coord = find_route(start, end, grid); draw(start, end, marked_grid, route_coord); # c to clear the screen elif event.key == pygame.K_c: print "clearing screen."; clear(rows); # go fullscreen elif event.key == pygame.K_f: if not full_sc: pygame.display.set_mode([1366, 768], pygame.FULLSCREEN); full_sc = True; rows = 15; clear(rows); else: pygame.display.set_mode(size); full_sc = False; # +/- key to change speed of animation elif event.key == pygame.K_LEFTBRACKET: if speed >= 0.1: print SPEED_UP; speed = speed_up(speed); print speed; else: print FASTEST; print speed; elif event.key == pygame.K_RIGHTBRACKET: if speed < 1.0: print SPEED_DOWN; speed = slow_down(speed); print speed; else: print SLOWEST print speed; # second method to quit program elif event.type == pygame.QUIT: print "program will now exit."; done = True; # limit to 20 fps clock.tick(20); # update the screen pygame.display.flip();

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  • Developing Schema Compare for Oracle (Part 2): Dependencies

    - by Simon Cooper
    In developing Schema Compare for Oracle, one of the issues we came across was the size of the databases. As detailed in my last blog post, we had to allow schema pre-filtering due to the number of objects in a standard Oracle database. Unfortunately, this leads to some quite tricky situations regarding object dependencies. This post explains how we deal with these dependencies. 1. Cross-schema dependencies Say, in the following database, you're populating SchemaA, and synchronizing SchemaA.Table1: SOURCE   TARGET CREATE TABLE SchemaA.Table1 ( Col1 NUMBER REFERENCES SchemaB.Table1(Col1));   CREATE TABLE SchemaA.Table1 ( Col1 VARCHAR2(100) REFERENCES SchemaB.Table1(Col1)); CREATE TABLE SchemaB.Table1 ( Col1 NUMBER PRIMARY KEY);   CREATE TABLE SchemaB.Table1 ( Col1 VARCHAR2(100) PRIMARY KEY); We need to do a rebuild of SchemaA.Table1 to change Col1 from a VARCHAR2(100) to a NUMBER. This consists of: Creating a table with the new schema Inserting data from the old table to the new table, with appropriate conversion functions (in this case, TO_NUMBER) Dropping the old table Rename new table to same name as old table Unfortunately, in this situation, the rebuild will fail at step 1, as we're trying to create a NUMBER column with a foreign key reference to a VARCHAR2(100) column. As we're only populating SchemaA, the naive implementation of the object population prefiltering (sticking a WHERE owner = 'SCHEMAA' on all the data dictionary queries) will generate an incorrect sync script. What we actually have to do is: Drop foreign key constraint on SchemaA.Table1 Rebuild SchemaB.Table1 Rebuild SchemaA.Table1, adding the foreign key constraint to the new table This means that in order to generate a correct synchronization script for SchemaA.Table1 we have to know what SchemaB.Table1 is, and that it also needs to be rebuilt to successfully rebuild SchemaA.Table1. SchemaB isn't the schema that the user wants to synchronize, but we still have to load the table and column information for SchemaB.Table1 the same way as any table in SchemaA. Fortunately, Oracle provides (mostly) complete dependency information in the dictionary views. Before we actually read the information on all the tables and columns in the database, we can get dependency information on all the objects that are either pointed at by objects in the schemas we’re populating, or point to objects in the schemas we’re populating (think about what would happen if SchemaB was being explicitly populated instead), with a suitable query on all_constraints (for foreign key relationships) and all_dependencies (for most other types of dependencies eg a function using another function). The extra objects found can then be included in the actual object population, and the sync wizard then has enough information to figure out the right thing to do when we get to actually synchronize the objects. Unfortunately, this isn’t enough. 2. Dependency chains The solution above will only get the immediate dependencies of objects in populated schemas. What if there’s a chain of dependencies? A.tbl1 -> B.tbl1 -> C.tbl1 -> D.tbl1 If we’re only populating SchemaA, the implementation above will only include B.tbl1 in the dependent objects list, whereas we might need to know about C.tbl1 and D.tbl1 as well, in order to ensure a modification on A.tbl1 can succeed. What we actually need is a graph traversal on the dependency graph that all_dependencies represents. Fortunately, we don’t have to read all the database dependency information from the server and run the graph traversal on the client computer, as Oracle provides a method of doing this in SQL – CONNECT BY. So, we can put all the dependencies we want to include together in big bag with UNION ALL, then run a SELECT ... CONNECT BY on it, starting with objects in the schema we’re populating. We should end up with all the objects that might be affected by modifications in the initial schema we’re populating. Good solution? Well, no. For one thing, it’s sloooooow. all_dependencies, on my test databases, has got over 110,000 rows in it, and the entire query, for which Oracle was creating a temporary table to hold the big bag of graph edges, was often taking upwards of two minutes. This is too long, and would only get worse for large databases. But it had some more fundamental problems than just performance. 3. Comparison dependencies Consider the following schema: SOURCE   TARGET CREATE TABLE SchemaA.Table1 ( Col1 NUMBER REFERENCES SchemaB.Table1(col1));   CREATE TABLE SchemaA.Table1 ( Col1 VARCHAR2(100)); CREATE TABLE SchemaB.Table1 ( Col1 NUMBER PRIMARY KEY);   CREATE TABLE SchemaB.Table1 ( Col1 VARCHAR2(100)); What will happen if we used the dependency algorithm above on the source & target database? Well, SchemaA.Table1 has a foreign key reference to SchemaB.Table1, so that will be included in the source database population. On the target, SchemaA.Table1 has no such reference. Therefore SchemaB.Table1 will not be included in the target database population. In the resulting comparison of the two objects models, what you will end up with is: SOURCE  TARGET SchemaA.Table1 -> SchemaA.Table1 SchemaB.Table1 -> (no object exists) When this comparison is synchronized, we will see that SchemaB.Table1 does not exist, so we will try the following sequence of actions: Create SchemaB.Table1 Rebuild SchemaA.Table1, with foreign key to SchemaB.Table1 Oops. Because the dependencies are only followed within a single database, we’ve tried to create an object that already exists. To fix this we can include any objects found as dependencies in the source or target databases in the object population of both databases. SchemaB.Table1 will then be included in the target database population, and we won’t try and create objects that already exist. All good? Well, consider the following schema (again, only explicitly populating SchemaA, and synchronizing SchemaA.Table1): SOURCE   TARGET CREATE TABLE SchemaA.Table1 ( Col1 NUMBER REFERENCES SchemaB.Table1(col1));   CREATE TABLE SchemaA.Table1 ( Col1 VARCHAR2(100)); CREATE TABLE SchemaB.Table1 ( Col1 NUMBER PRIMARY KEY);   CREATE TABLE SchemaB.Table1 ( Col1 VARCHAR2(100) PRIMARY KEY); CREATE TABLE SchemaC.Table1 ( Col1 NUMBER);   CREATE TABLE SchemaC.Table1 ( Col1 VARCHAR2(100) REFERENCES SchemaB.Table1); Although we’re now including SchemaB.Table1 on both sides of the comparison, there’s a third table (SchemaC.Table1) that we don’t know about that will cause the rebuild of SchemaB.Table1 to fail if we try and synchronize SchemaA.Table1. That’s because we’re only running the dependency query on the schemas we’re explicitly populating; to solve this issue, we would have to run the dependency query again, but this time starting the graph traversal from the objects found in the other database. Furthermore, this dependency chain could be arbitrarily extended.This leads us to the following algorithm for finding all the dependencies of a comparison: Find initial dependencies of schemas the user has selected to compare on the source and target Include these objects in both the source and target object populations Run the dependency query on the source, starting with the objects found as dependents on the target, and vice versa Repeat 2 & 3 until no more objects are found For the schema above, this will result in the following sequence of actions: Find initial dependenciesSchemaA.Table1 -> SchemaB.Table1 found on sourceNo objects found on target Include objects in both source and targetSchemaB.Table1 included in source and target Run dependency query, starting with found objectsNo objects to start with on sourceSchemaB.Table1 -> SchemaC.Table1 found on target Include objects in both source and targetSchemaC.Table1 included in source and target Run dependency query on found objectsNo objects found in sourceNo objects to start with in target Stop This will ensure that we include all the necessary objects to make any synchronization work. However, there is still the issue of query performance; the CONNECT BY on the entire database dependency graph is still too slow. After much sitting down and drawing complicated diagrams, we decided to move the graph traversal algorithm from the server onto the client (which turned out to run much faster on the client than on the server); and to ensure we don’t read the entire dependency graph onto the client we also pull the graph across in bits – we start off with dependency edges involving schemas selected for explicit population, and whenever the graph traversal comes across a dependency reference to a schema we don’t yet know about a thunk is hit that pulls in the dependency information for that schema from the database. We continue passing more dependent objects back and forth between the source and target until no more dependency references are found. This gives us the list of all the extra objects to populate in the source and target, and object population can then proceed. 4. Object blacklists and fast dependencies When we tested this solution, we were puzzled in that in some of our databases most of the system schemas (WMSYS, ORDSYS, EXFSYS, XDB, etc) were being pulled in, and this was increasing the database registration and comparison time quite significantly. After debugging, we discovered that the culprits were database tables that used one of the Oracle PL/SQL types (eg the SDO_GEOMETRY spatial type). These were creating a dependency chain from the database tables we were populating to the system schemas, and hence pulling in most of the system objects in that schema. To solve this we introduced blacklists of objects we wouldn’t follow any dependency chain through. As well as the Oracle-supplied PL/SQL types (MDSYS.SDO_GEOMETRY, ORDSYS.SI_COLOR, among others) we also decided to blacklist the entire PUBLIC and SYS schemas, as any references to those would likely lead to a blow up in the dependency graph that would massively increase the database registration time, and could result in the client running out of memory. Even with these improvements, each dependency query was taking upwards of a minute. We discovered from Oracle execution plans that there were some columns, with dependency information we required, that were querying system tables with no indexes on them! To cut a long story short, running the following query: SELECT * FROM all_tab_cols WHERE data_type_owner = ‘XDB’; results in a full table scan of the SYS.COL$ system table! This single clause was responsible for over half the execution time of the dependency query. Hence, the ‘Ignore slow dependencies’ option was born – not querying this and a couple of similar clauses to drastically speed up the dependency query execution time, at the expense of producing incorrect sync scripts in rare edge cases. Needless to say, along with the sync script action ordering, the dependency code in the database registration is one of the most complicated and most rewritten parts of the Schema Compare for Oracle engine. The beta of Schema Compare for Oracle is out now; if you find a bug in it, please do tell us so we can get it fixed!

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  • .NET file Decryption - Bad Data

    - by Jon
    I am in the process of rewriting an old application. The old app stored data in a scoreboard file that was encrypted with the following code: private const String SSecretKey = @"?B?n?Mj?"; public DataTable GetScoreboardFromFile() { FileInfo f = new FileInfo(scoreBoardLocation); if (!f.Exists) { return setupNewScoreBoard(); } DESCryptoServiceProvider DES = new DESCryptoServiceProvider(); //A 64 bit key and IV is required for this provider. //Set secret key For DES algorithm. DES.Key = ASCIIEncoding.ASCII.GetBytes(SSecretKey); //Set initialization vector. DES.IV = ASCIIEncoding.ASCII.GetBytes(SSecretKey); //Create a file stream to read the encrypted file back. FileStream fsread = new FileStream(scoreBoardLocation, FileMode.Open, FileAccess.Read); //Create a DES decryptor from the DES instance. ICryptoTransform desdecrypt = DES.CreateDecryptor(); //Create crypto stream set to read and do a //DES decryption transform on incoming bytes. CryptoStream cryptostreamDecr = new CryptoStream(fsread, desdecrypt, CryptoStreamMode.Read); DataTable dTable = new DataTable("scoreboard"); dTable.ReadXml(new StreamReader(cryptostreamDecr)); cryptostreamDecr.Close(); fsread.Close(); return dTable; } This works fine. I have copied the code into my new app so that I can create a legacy loader and convert the data into the new format. The problem is I get a "Bad Data" error: System.Security.Cryptography.CryptographicException was unhandled Message="Bad Data.\r\n" Source="mscorlib" The error fires at this line: dTable.ReadXml(new StreamReader(cryptostreamDecr)); The encrypted file was created today on the same machine with the old code. I guess that maybe the encryption / decryption process uses the application name / file or something and therefore means I can not open it. Does anyone have an idea as to: A) Be able explain why this isn't working? B) Offer a solution that would allow me to be able to open files that were created with the legacy application and be able to convert them please? Here is the whole class that deals with loading and saving the scoreboard: using System; using System.Collections.Generic; using System.Text; using System.Security.Cryptography; using System.Runtime.InteropServices; using System.IO; using System.Data; using System.Xml; using System.Threading; namespace JawBreaker { [Serializable] class ScoreBoardLoader { private Jawbreaker jawbreaker; private String sSecretKey = @"?B?n?Mj?"; private String scoreBoardFileLocation = ""; private bool keepScoreBoardUpdated = true; private int intTimer = 180000; public ScoreBoardLoader(Jawbreaker jawbreaker, String scoreBoardFileLocation) { this.jawbreaker = jawbreaker; this.scoreBoardFileLocation = scoreBoardFileLocation; } // Call this function to remove the key from memory after use for security [System.Runtime.InteropServices.DllImport("KERNEL32.DLL", EntryPoint = "RtlZeroMemory")] public static extern bool ZeroMemory(IntPtr Destination, int Length); // Function to Generate a 64 bits Key. private string GenerateKey() { // Create an instance of Symetric Algorithm. Key and IV is generated automatically. DESCryptoServiceProvider desCrypto = (DESCryptoServiceProvider)DESCryptoServiceProvider.Create(); // Use the Automatically generated key for Encryption. return ASCIIEncoding.ASCII.GetString(desCrypto.Key); } public void writeScoreboardToFile() { DataTable tempScoreBoard = getScoreboardFromFile(); //add in the new scores to the end of the file. for (int i = 0; i < jawbreaker.Scoreboard.Rows.Count; i++) { DataRow row = tempScoreBoard.NewRow(); row.ItemArray = jawbreaker.Scoreboard.Rows[i].ItemArray; tempScoreBoard.Rows.Add(row); } //before it is written back to the file make sure we update the sync info if (jawbreaker.SyncScoreboard) { //connect to webservice, login and update all the scores that have not been synced. for (int i = 0; i < tempScoreBoard.Rows.Count; i++) { try { //check to see if that row has been synced to the server if (!Boolean.Parse(tempScoreBoard.Rows[i].ItemArray[7].ToString())) { //sync info to server //update the row to say that it has been updated object[] tempArray = tempScoreBoard.Rows[i].ItemArray; tempArray[7] = true; tempScoreBoard.Rows[i].ItemArray = tempArray; tempScoreBoard.AcceptChanges(); } } catch (Exception ex) { jawbreaker.writeErrorToLog("ERROR OCCURED DURING SYNC TO SERVER UPDATE: " + ex.Message); } } } FileStream fsEncrypted = new FileStream(scoreBoardFileLocation, FileMode.Create, FileAccess.Write); DESCryptoServiceProvider DES = new DESCryptoServiceProvider(); DES.Key = ASCIIEncoding.ASCII.GetBytes(sSecretKey); DES.IV = ASCIIEncoding.ASCII.GetBytes(sSecretKey); ICryptoTransform desencrypt = DES.CreateEncryptor(); CryptoStream cryptostream = new CryptoStream(fsEncrypted, desencrypt, CryptoStreamMode.Write); MemoryStream ms = new MemoryStream(); tempScoreBoard.WriteXml(ms, XmlWriteMode.WriteSchema); ms.Position = 0; byte[] bitarray = new byte[ms.Length]; ms.Read(bitarray, 0, bitarray.Length); cryptostream.Write(bitarray, 0, bitarray.Length); cryptostream.Close(); ms.Close(); //now the scores have been added to the file remove them from the datatable jawbreaker.Scoreboard.Rows.Clear(); } public void startPeriodicScoreboardWriteToFile() { while (keepScoreBoardUpdated) { //three minute sleep. Thread.Sleep(intTimer); writeScoreboardToFile(); } } public void stopPeriodicScoreboardWriteToFile() { keepScoreBoardUpdated = false; } public int IntTimer { get { return intTimer; } set { intTimer = value; } } public DataTable getScoreboardFromFile() { FileInfo f = new FileInfo(scoreBoardFileLocation); if (!f.Exists) { jawbreaker.writeInfoToLog("Scoreboard not there so creating new one"); return setupNewScoreBoard(); } else { DESCryptoServiceProvider DES = new DESCryptoServiceProvider(); //A 64 bit key and IV is required for this provider. //Set secret key For DES algorithm. DES.Key = ASCIIEncoding.ASCII.GetBytes(sSecretKey); //Set initialization vector. DES.IV = ASCIIEncoding.ASCII.GetBytes(sSecretKey); //Create a file stream to read the encrypted file back. FileStream fsread = new FileStream(scoreBoardFileLocation, FileMode.Open, FileAccess.Read); //Create a DES decryptor from the DES instance. ICryptoTransform desdecrypt = DES.CreateDecryptor(); //Create crypto stream set to read and do a //DES decryption transform on incoming bytes. CryptoStream cryptostreamDecr = new CryptoStream(fsread, desdecrypt, CryptoStreamMode.Read); DataTable dTable = new DataTable("scoreboard"); dTable.ReadXml(new StreamReader(cryptostreamDecr)); cryptostreamDecr.Close(); fsread.Close(); return dTable; } } public DataTable setupNewScoreBoard() { //scoreboard info into dataset DataTable scoreboard = new DataTable("scoreboard"); scoreboard.Columns.Add(new DataColumn("playername", System.Type.GetType("System.String"))); scoreboard.Columns.Add(new DataColumn("score", System.Type.GetType("System.Int32"))); scoreboard.Columns.Add(new DataColumn("ballnumber", System.Type.GetType("System.Int32"))); scoreboard.Columns.Add(new DataColumn("xsize", System.Type.GetType("System.Int32"))); scoreboard.Columns.Add(new DataColumn("ysize", System.Type.GetType("System.Int32"))); scoreboard.Columns.Add(new DataColumn("gametype", System.Type.GetType("System.String"))); scoreboard.Columns.Add(new DataColumn("date", System.Type.GetType("System.DateTime"))); scoreboard.Columns.Add(new DataColumn("synced", System.Type.GetType("System.Boolean"))); scoreboard.AcceptChanges(); return scoreboard; } private void Run() { // For additional security Pin the key. GCHandle gch = GCHandle.Alloc(sSecretKey, GCHandleType.Pinned); // Remove the Key from memory. ZeroMemory(gch.AddrOfPinnedObject(), sSecretKey.Length * 2); gch.Free(); } } }

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