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• First Experience with Web Services

  When I first started programming with Microsoft .Net (1.0 Framework) I had a strong desire to learn how search engines indexed web sites. At that time I was a working as a search engine spammer creating web pages to generate traffic for specific themes for various clients. One way I attempted to better understand .Net was to build a web spider that analyzed web pages on demand. An example of the spider is hosted at AddLinkz.com. After my spider was built I had no real idea what I could/should do with it until I found the MSN Search API. I used this web service to compare its results with my spider. Additionally, I used the API to feed my .Net web spider new URLs from the API based on specific search terms. MSN’s search API was very easy to use, I just had to request information by calling a web URL with parameters via a Get request and the results were returned in XML. At that time all requests were limited to XML responses and a maximum of 1,000 results per query.   Since then the entire API has gone through several reconstructions, rebranding and new search services.  Microsoft’s new Bing API replaced the older MSN search API and added several new search capabilities. These new features allow search data to be returned for web searches, image searches, new searches, and related search terms to name a few. Bing API Version 2.0 SourceTypes Web Searches for web content Sushi Image Searches for images on the web Sushi News Searches news stories Sushi InstantAnswer Searches Encarta online what is sushi, convert 5 feet to meters, x*5=7, and 2 plus 2 Spell Searches Encarta dictionary for spelling suggestions Phonebook Searches phonebook entries sushi in Los Angeles RelatedSearch Returns the query strings most similar to yours Ad Returns advertisements to incorporate with results I currently plan to start using the web search feature from the new Bing 2.0 API in an open source project related to exception management. Currently, it is still in the conception phase.

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• MySQL on a laptop for remote workers - MyISAM keeps corrupting

  - by Jonathon

  We have an application that is used by remote, mobile workers. It intalls WAMP (Server2Go) on a laptop and uses MySQL to store data locally. All tables are MyISAM. Once a day, the workers sync the database to our central server via HTTP scripts that query the data and post it to our site. The problem is that many of these laptop database tables are corrupting continually. It appears that MySQL acts like it saves the information (I don't get any query errors), but the table gets corrupt. I have to repair the table constantly (which removes several rows of data in the process). Does anyone have any ideas about how to work around this problem? Would it be wise to switch to InnoDB on the laptops? How about a different database system altogether. I have looked at MySQL Embedded, but it appears to be the same engine as the regular MySQL.

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• BI-Applications Special Price Promotion for Partners

  - by Mike.Hallett(at)Oracle-BI&EPM

  Partners should keep in mind the “Midsize Market” pricing promotion for BI-Applications solution packages, with reduced minimums applicable to Oracle's Business Intelligence Products, and a pre-approved 50% discount. ·       Partners additionally get their normal e-business reseller discount. This now makes it most attractive to offer the pre-built BI-Applications such as Manufacturing Analytics, Financial Analytics, Procurement and Spend Analytics, Project Analytics, and Human Resources Analytics, to both customers newly implementing Oracle ERP, and for the many existing Oracle ERP (eBusiness suite, Peoplesoft and JDE) customers. To answer any questions, and to get the partner document with further details of this offer, or to work with us on our local sales campaigns targeting existing ERP customers, please send your query to [email protected] or [email protected]: or discuss it with your local Oracle Sales or Channel representative for Applications to Midsize Enterprises.  This promotion is ONLY for End Customers whose organisations have an Annual Revenue (or Public Sector Budget) below $500 million, and who are based in Europe, the Middle East or Africa. For more information see the orginal article, “New fy13 BI-Applications Price Promotion for MIDSIZE CUSTOMERS”  and send your query to [email protected].

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• Does Hauppauge WinTV HVR-900 (r2) [USB ID 2040:6502] work with ubuntu 12.04 LTS?

  - by nightfly

  I have this DVB+Analog usb tv tuner Hauppauge WinTV HVR-900 (r2) [USB ID 2040:6502]. This used to work under ubuntu 10.04 LTS. But in 12.04 there seems to be a problem. I have linux-firmware-nonfree and ivtv-utils installed. I am running Ubuntu 12.04.1 LTS 64 bit with all updates installed and the default unity environment. When I run mplayer tv:// -tv driver=v4l2:device=/dev/video1:input=1:norm=PAL I get a solid green screen and no picture. Here input 1 is the composite input of the card. MPlayer svn r34540 (Ubuntu), built with gcc-4.6 (C) 2000-2012 MPlayer Team mplayer: could not connect to socket mplayer: No such file or directory Failed to open LIRC support. You will not be able to use your remote control. Playing tv://. TV file format detected. Selected driver: v4l2 name: Video 4 Linux 2 input author: Martin Olschewski comment: first try, more to come ;-) Selected device: Hauppauge WinTV HVR 900 (R2) Tuner cap: Tuner rxs: Capabilities: video capture VBI capture device tuner audio read/write streaming supported norms: 0 = NTSC; 1 = NTSC-M; 2 = NTSC-M-JP; 3 = NTSC-M-KR; 4 = NTSC-443; 5 = PAL; 6 = PAL-BG; 7 = PAL-H; 8 = PAL-I; 9 = PAL-DK; 10 = PAL-M; 11 = PAL-N; 12 = PAL-Nc; 13 = PAL-60; 14 = SECAM; 15 = SECAM-B; 16 = SECAM-G; 17 = SECAM-H; 18 = SECAM-DK; 19 = SECAM-L; 20 = SECAM-Lc; inputs: 0 = Television; 1 = Composite1; 2 = S-Video; Current input: 1 Current format: YUYV v4l2: current audio mode is : MONO v4l2: ioctl set format failed: Invalid argument v4l2: ioctl set format failed: Invalid argument v4l2: ioctl set format failed: Invalid argument v4l2: ioctl query control failed: Invalid argument v4l2: ioctl query control failed: Invalid argument v4l2: ioctl query control failed: Invalid argument v4l2: ioctl query control failed: Invalid argument Failed to open VDPAU backend libvdpau_nvidia.so: cannot open shared object file: No such file or directory [vdpau] Error when calling vdp_device_create_x11: 1 ========================================================================== Opening video decoder: [raw] RAW Uncompressed Video Movie-Aspect is undefined - no prescaling applied. VO: [xv] 640x480 = 640x480 Packed YUY2 Selected video codec: [rawyuy2] vfm: raw (RAW YUY2) ========================================================================== Audio: no sound Starting playback... v4l2: select timeout V: 0.0 2/ 2 ??% ??% ??,?% 0 0 v4l2: select timeout V: 0.0 4/ 4 ??% ??% ??,?% 0 0 v4l2: select timeout V: 0.0 6/ 6 ??% ??% ??,?% 0 0 v4l2: select timeout v4l2: 0 frames successfully processed, 1 frames dropped. Exiting... (Quit) Here is the dmesg of the card when plugged in.. [12742.228097] usb 1-4: new high-speed USB device number 3 using ehci_hcd [12742.367289] em28xx: New device WinTV HVR-900 @ 480 Mbps (2040:6502, interface 0, class 0) [12742.367296] em28xx: Audio Vendor Class interface 0 found [12742.367585] em28xx #0: chip ID is em2882/em2883 [12742.550086] em28xx #0: i2c eeprom 00: 1a eb 67 95 40 20 02 65 d0 12 5c 03 82 1e 6a 18 [12742.550104] em28xx #0: i2c eeprom 10: 00 00 24 57 66 07 01 00 00 00 00 00 00 00 00 00 [12742.550120] em28xx #0: i2c eeprom 20: 46 00 01 00 f0 10 02 00 b8 00 00 00 5b e0 00 00 [12742.550135] em28xx #0: i2c eeprom 30: 00 00 20 40 20 6e 02 20 10 01 01 01 00 00 00 00 [12742.550150] em28xx #0: i2c eeprom 40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [12742.550165] em28xx #0: i2c eeprom 50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [12742.550181] em28xx #0: i2c eeprom 60: 00 00 00 00 00 00 00 00 00 00 18 03 34 00 30 00 [12742.550196] em28xx #0: i2c eeprom 70: 32 00 37 00 38 00 32 00 33 00 39 00 30 00 31 00 [12742.550211] em28xx #0: i2c eeprom 80: 00 00 1e 03 57 00 69 00 6e 00 54 00 56 00 20 00 [12742.550226] em28xx #0: i2c eeprom 90: 48 00 56 00 52 00 2d 00 39 00 30 00 30 00 00 00 [12742.550241] em28xx #0: i2c eeprom a0: 84 12 00 00 05 50 1a 7f d4 78 23 fa fd d0 28 89 [12742.550257] em28xx #0: i2c eeprom b0: ff 00 00 00 04 84 0a 00 01 01 20 77 00 40 1d b7 [12742.550272] em28xx #0: i2c eeprom c0: 13 f0 74 02 01 00 01 79 63 00 00 00 00 00 00 00 [12742.550287] em28xx #0: i2c eeprom d0: 84 12 00 00 05 50 1a 7f d4 78 23 fa fd d0 28 89 [12742.550302] em28xx #0: i2c eeprom e0: ff 00 00 00 04 84 0a 00 01 01 20 77 00 40 1d b7 [12742.550317] em28xx #0: i2c eeprom f0: 13 f0 74 02 01 00 01 79 63 00 00 00 00 00 00 00 [12742.550334] em28xx #0: EEPROM ID= 0x9567eb1a, EEPROM hash = 0x2bbf3bdd [12742.550338] em28xx #0: EEPROM info: [12742.550340] em28xx #0: AC97 audio (5 sample rates) [12742.550343] em28xx #0: 500mA max power [12742.550346] em28xx #0: Table at 0x24, strings=0x1e82, 0x186a, 0x0000 [12742.552590] em28xx #0: Identified as Hauppauge WinTV HVR 900 (R2) (card=18) [12742.555516] tveeprom 15-0050: Hauppauge model 65018, rev B2C0, serial# 1292061 [12742.555523] tveeprom 15-0050: tuner model is Xceive XC3028 (idx 120, type 71) [12742.555529] tveeprom 15-0050: TV standards PAL(B/G) PAL(I) PAL(D/D1/K) ATSC/DVB Digital (eeprom 0xd4) [12742.555534] tveeprom 15-0050: audio processor is None (idx 0) [12742.555537] tveeprom 15-0050: has radio [12742.570297] tuner 15-0061: Tuner -1 found with type(s) Radio TV. [12742.570327] xc2028 15-0061: creating new instance [12742.570332] xc2028 15-0061: type set to XCeive xc2028/xc3028 tuner [12742.573685] xc2028 15-0061: Loading 80 firmware images from xc3028-v27.fw, type: xc2028 firmware, ver 2.7 [12742.624056] xc2028 15-0061: Loading firmware for type=BASE MTS (5), id 0000000000000000. [12744.126591] xc2028 15-0061: Loading firmware for type=MTS (4), id 000000000000b700. [12744.153586] xc2028 15-0061: Loading SCODE for type=MTS LCD NOGD MONO IF SCODE HAS_IF_4500 (6002b004), id 000000000000b700. [12744.280963] Registered IR keymap rc-hauppauge [12744.281151] input: em28xx IR (em28xx #0) as /devices/pci0000:00/0000:00:1a.7/usb1/1-4/rc/rc1/input10 [12744.281541] rc1: em28xx IR (em28xx #0) as /devices/pci0000:00/0000:00:1a.7/usb1/1-4/rc/rc1 [12744.282454] em28xx #0: Config register raw data: 0xd0 [12744.284709] em28xx #0: AC97 vendor ID = 0xffffffff [12744.285829] em28xx #0: AC97 features = 0x6a90 [12744.285832] em28xx #0: Empia 202 AC97 audio processor detected [12744.359211] em28xx #0: v4l2 driver version 0.1.3 [12744.404066] xc2028 15-0061: Loading firmware for type=BASE F8MHZ MTS (7), id 0000000000000000. [12745.915089] MTS (4), id 00000000000000ff: [12745.915100] xc2028 15-0061: Loading firmware for type=MTS (4), id 0000000100000007. [12746.161668] em28xx #0: V4L2 video device registered as video1 [12746.161673] em28xx #0: V4L2 VBI device registered as vbi0 [12746.162845] em28xx-audio.c: probing for em28xx Audio Vendor Class [12746.162848] em28xx-audio.c: Copyright (C) 2006 Markus Rechberger [12746.162851] em28xx-audio.c: Copyright (C) 2007-2011 Mauro Carvalho Chehab [12746.221099] xc2028 15-0061: attaching existing instance [12746.221105] xc2028 15-0061: type set to XCeive xc2028/xc3028 tuner [12746.221109] em28xx #0: em28xx #0/2: xc3028 attached [12746.221113] DVB: registering new adapter (em28xx #0) [12746.221118] DVB: registering adapter 0 frontend 0 (Micronas DRXD DVB-T)... [12746.221869] em28xx #0: Successfully loaded em28xx-dvb [13111.196055] xc2028 15-0061: Loading firmware for type=BASE F8MHZ MTS (7), id 0000000000000000. [13112.720062] MTS (4), id 00000000000000ff: [13112.720072] xc2028 15-0061: Loading firmware for type=MTS (4), id 0000000100000007. [13214.956057] xc2028 15-0061: Loading firmware for type=BASE F8MHZ MTS (7), id 0000000000000000. [13216.479806] MTS (4), id 00000000000000ff: [13216.479816] xc2028 15-0061: Loading firmware for type=MTS (4), id 0000000100000007. [13276.408056] xc2028 15-0061: Loading firmware for type=BASE F8MHZ MTS (7), id 0000000000000000. [13277.932093] MTS (4), id 00000000000000ff: [13277.932104] xc2028 15-0061: Loading firmware for type=MTS (4), id 0000000100000007. [13305.032076] xc2028 15-0061: Loading firmware for type=BASE F8MHZ MTS (7), id 0000000000000000. [13306.556449] MTS (4), id 00000000000000ff: [13306.556460] xc2028 15-0061: Loading firmware for type=MTS (4), id 0000000100000007. [13392.236055] xc2028 15-0061: Loading firmware for type=BASE F8MHZ MTS (7), id 0000000000000000. [13393.760123] MTS (4), id 00000000000000ff: [13393.760133] xc2028 15-0061: Loading firmware for type=MTS (4), id 0000000100000007. [13637.534053] usb 1-4: USB disconnect, device number 3 [13637.534183] em28xx #0: disconnecting em28xx #0 video [13637.560214] em28xx #0: V4L2 device vbi0 deregistered [13637.560335] em28xx #0: V4L2 device video1 deregistered [13637.561237] xc2028 15-0061: destroying instance [13639.772120] usb 1-4: new high-speed USB device number 4 using ehci_hcd [13639.911351] em28xx: New device WinTV HVR-900 @ 480 Mbps (2040:6502, interface 0, class 0) [13639.911357] em28xx: Audio Vendor Class interface 0 found [13639.911637] em28xx #0: chip ID is em2882/em2883 [13640.094262] em28xx #0: i2c eeprom 00: 1a eb 67 95 40 20 02 65 d0 12 5c 03 82 1e 6a 18 [13640.094280] em28xx #0: i2c eeprom 10: 00 00 24 57 66 07 01 00 00 00 00 00 00 00 00 00 [13640.094295] em28xx #0: i2c eeprom 20: 46 00 01 00 f0 10 02 00 b8 00 00 00 5b e0 00 00 [13640.094311] em28xx #0: i2c eeprom 30: 00 00 20 40 20 6e 02 20 10 01 01 01 00 00 00 00 [13640.094326] em28xx #0: i2c eeprom 40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [13640.094341] em28xx #0: i2c eeprom 50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [13640.094356] em28xx #0: i2c eeprom 60: 00 00 00 00 00 00 00 00 00 00 18 03 34 00 30 00 [13640.094371] em28xx #0: i2c eeprom 70: 32 00 37 00 38 00 32 00 33 00 39 00 30 00 31 00 [13640.094386] em28xx #0: i2c eeprom 80: 00 00 1e 03 57 00 69 00 6e 00 54 00 56 00 20 00 [13640.094401] em28xx #0: i2c eeprom 90: 48 00 56 00 52 00 2d 00 39 00 30 00 30 00 00 00 [13640.094416] em28xx #0: i2c eeprom a0: 84 12 00 00 05 50 1a 7f d4 78 23 fa fd d0 28 89 [13640.094432] em28xx #0: i2c eeprom b0: ff 00 00 00 04 84 0a 00 01 01 20 77 00 40 1d b7 [13640.094447] em28xx #0: i2c eeprom c0: 13 f0 74 02 01 00 01 79 63 00 00 00 00 00 00 00 [13640.094462] em28xx #0: i2c eeprom d0: 84 12 00 00 05 50 1a 7f d4 78 23 fa fd d0 28 89 [13640.094477] em28xx #0: i2c eeprom e0: ff 00 00 00 04 84 0a 00 01 01 20 77 00 40 1d b7 [13640.094492] em28xx #0: i2c eeprom f0: 13 f0 74 02 01 00 01 79 63 00 00 00 00 00 00 00 [13640.094509] em28xx #0: EEPROM ID= 0x9567eb1a, EEPROM hash = 0x2bbf3bdd [13640.094512] em28xx #0: EEPROM info: [13640.094515] em28xx #0: AC97 audio (5 sample rates) [13640.094517] em28xx #0: 500mA max power [13640.094521] em28xx #0: Table at 0x24, strings=0x1e82, 0x186a, 0x0000 [13640.097391] em28xx #0: Identified as Hauppauge WinTV HVR 900 (R2) (card=18) [13640.099617] tveeprom 15-0050: Hauppauge model 65018, rev B2C0, serial# 1292061 [13640.099623] tveeprom 15-0050: tuner model is Xceive XC3028 (idx 120, type 71) [13640.099629] tveeprom 15-0050: TV standards PAL(B/G) PAL(I) PAL(D/D1/K) ATSC/DVB Digital (eeprom 0xd4) [13640.099634] tveeprom 15-0050: audio processor is None (idx 0) [13640.099637] tveeprom 15-0050: has radio [13640.112849] tuner 15-0061: Tuner -1 found with type(s) Radio TV. [13640.112877] xc2028 15-0061: creating new instance [13640.112882] xc2028 15-0061: type set to XCeive xc2028/xc3028 tuner [13640.115930] xc2028 15-0061: Loading 80 firmware images from xc3028-v27.fw, type: xc2028 firmware, ver 2.7 [13640.164057] xc2028 15-0061: Loading firmware for type=BASE MTS (5), id 0000000000000000. [13641.666643] xc2028 15-0061: Loading firmware for type=MTS (4), id 000000000000b700. [13641.693262] xc2028 15-0061: Loading SCODE for type=MTS LCD NOGD MONO IF SCODE HAS_IF_4500 (6002b004), id 000000000000b700. [13641.820765] Registered IR keymap rc-hauppauge [13641.820958] input: em28xx IR (em28xx #0) as /devices/pci0000:00/0000:00:1a.7/usb1/1-4/rc/rc2/input11 [13641.821335] rc2: em28xx IR (em28xx #0) as /devices/pci0000:00/0000:00:1a.7/usb1/1-4/rc/rc2 [13641.822256] em28xx #0: Config register raw data: 0xd0 [13641.824526] em28xx #0: AC97 vendor ID = 0xffffffff [13641.825503] em28xx #0: AC97 features = 0x6a90 [13641.825507] em28xx #0: Empia 202 AC97 audio processor detected [13641.899015] em28xx #0: v4l2 driver version 0.1.3 [13641.944064] xc2028 15-0061: Loading firmware for type=BASE F8MHZ MTS (7), id 0000000000000000. [13643.470765] MTS (4), id 00000000000000ff: [13643.470776] xc2028 15-0061: Loading firmware for type=MTS (4), id 0000000100000007. [13643.717713] em28xx #0: V4L2 video device registered as video1 [13643.717718] em28xx #0: V4L2 VBI device registered as vbi0 [13643.718770] em28xx-audio.c: probing for em28xx Audio Vendor Class [13643.718775] em28xx-audio.c: Copyright (C) 2006 Markus Rechberger [13643.718778] em28xx-audio.c: Copyright (C) 2007-2011 Mauro Carvalho Chehab [13643.777148] xc2028 15-0061: attaching existing instance [13643.777154] xc2028 15-0061: type set to XCeive xc2028/xc3028 tuner [13643.777158] em28xx #0: em28xx #0/2: xc3028 attached [13643.777162] DVB: registering new adapter (em28xx #0) [13643.777167] DVB: registering adapter 0 frontend 0 (Micronas DRXD DVB-T)... [13643.777876] em28xx #0: Successfully loaded em28xx-dvb And here goes the lsmod output lsmod|grep em28xx em28xx_dvb 18579 0 dvb_core 110619 1 em28xx_dvb em28xx_alsa 18305 0 em28xx 109365 2 em28xx_dvb,em28xx_alsa v4l2_common 16454 3 tuner,tvp5150,em28xx videobuf_vmalloc 13589 1 em28xx videobuf_core 26390 2 em28xx,videobuf_vmalloc rc_core 26412 10 rc_hauppauge,ir_lirc_codec,ir_mce_kbd_decoder,ir_sony_decoder,ir_jvc_decoder,ir_rc6_decoder,ir_rc5_decoder,em28xx,ir_nec_decoder snd_pcm 97188 3 em28xx_alsa,snd_hda_intel,snd_hda_codec tveeprom 21249 1 em28xx videodev 98259 5 tuner,tvp5150,em28xx,v4l2_common,uvcvideo snd 78855 14 em28xx_alsa,snd_hda_codec_conexant,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_rawmidi,snd_seq,snd_timer,snd_seq_device Isn't this driver mainline now? Or this card is not supported? Or the analog functionality is screwed? I need the analog capture working for this card. Please help!

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• Simple queries occasionally running very slowly

  - by Johan

  I have some very simple queries that occasionally run very slowly. The table viewed_sites has about 10 - 20 rows. Running EXPLAIN ANALYZE always gives a runtime of less than 3 milliseconds. When the query is run automatically (every 10 seconds) it occasionally takes over a second to run. The query: INSERT INTO ga.viewed_sites (site_id) VALUES ('gop2') The table: CREATE TABLE viewed_sites ( site_id character varying(4) NOT NULL, last_viewed timestamp with time zone DEFAULT now() NOT NULL ); The (occasional) log result: 2010-05-24 15:47:55 UTC LOG: duration: 1044.632 ms statement: INSERT INTO ga.viewed_sites (site_id) VALUES ('gop2') It's a horribly vague question, but what could be causing this? I suppose it comes down to CPU, RAM, HDD or some combination of the above. Postgresql 8.3, Ubuntu 8.04 Intel(R) Core(TM)2 Duo CPU E6750 @ 2.66GHz 2 GiB RAM

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• Database Driven Web Application, C# Front-End and F# Back-End meaning

  - by user1473053

  Hi I am an intern working with ASP.NET. My current task is to make a website which will incorporate some jquery viewing features. This project seems to me will be primarily dealing with reading data from a database and making graphs out of them. This will require me to make custom queries from whatever the client is looking at. I think it is going to be what this guy calls an Ad Hoc Query tool My plan for this is to make it a database-driven website. So I can utilize the jquery dynamic viewing capabilities. I stumbled upon the functional programming paradigm and found F#. I read that because of it's functional programming paradigm, it makes it a good language to do asynchronous functions. I read about how you can use this with LINQ to SQL and how easy it is to make queries without actually putting the query language in. I understand the concept of the MVC design pattern. But I don't understand what they mean about C# being the front-end and F# being the back-end. Can someone clarify this to me? Also what are your thoughts about doing this project in this way? Any comments and thoughts are greatly appreciated. I feel as if learning F# will be a great learning experience for me. My guess is that the F# back-end is like the part where it controls the calls to the database. F# is possibly the model part of the design pattern. And C# is the controller. So HTML, Javascript and Jquery stuff will be my View design pattern. Clarify please?

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• OPTIONS request vs GET in Ajax

  - by user41172

  I have a PHP/javascript app that queries and returns info using an ajax request. On every server I've used so far, this works as expected, passing an Ajax GET request to the server and returning json data. On a new install, the query fails and returns nothing-- I inspected the request and it turns out that rather than passing the query as a GET, the server is passing it as an OPTIONS request. Is there any reason for this? I have no idea why this might happen. THanks!

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• Working with Reporting Services Filters – Part 2: The LIKE Operator

  - by smisner

  In the first post of this series, I introduced the use of filters within the report rather than in the query. I included a list of filter operators, and then focused on the use of the IN operator. As I mentioned in the previous post, the use of some of these operators is not obvious, so I'm going to spend some time explaining them as well as describing ways that you can use report filters in Reporting Services in this series of blog posts. Now let's look at the LIKE operator. If you write T-SQL queries, you've undoubtedly used the LIKE operator to produce a query using the % symbol as a wildcard for multiple characters like this: select * from DimProduct where EnglishProductName like '%Silver%' And you know that you can use the _ symbol as a wildcard for a single character like this: select * from DimProduct where EnglishProductName like '_L Mountain Frame - Black, 4_'   So when you encounter the LIKE operator in a Reporting Services filter, you probably expect it to work the same way. But it doesn't. You use the * symbol as a wildcard for multiple characters as shown here: Expression Data Type Operator Value [EnglishProductName] Text Like *Silver* Note that you don’t have to include quotes around the string that you use for comparison. Books Online has an example of using the % symbol as a wildcard for a single character, but I have not been able to successfully use this wildcard. If anyone has a working example, I’d love to see it!

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• Prevent Click Fraud in Advertisement system with PHP and Javascript

  - by CodeDevelopr

  I would like to build an Advertising project with PHP, MySQL, and Javascript. I am talking about something like... Google Adsense BuySellAds.com Any other advertising platform My question is mainly, what do I need to look out for to prevent people cheating the system and any other issues I may encounter? My design concept. An Advertisement is a record in the Database, when a page is loaded, using Javascript, it calls my server which in turn will use a PHP script to query the Database and get a random Advertisement. (It may do kore like get an ad based on demographics or other criteria as well) The PHP script will then return the Advertisement to the server/website that is calling it and show it on the page as an Image that will have a special tracking link. I will need to... Count all impressions (when the Advertisement is shown on the page) Count all clicks on the Advertisement link Count all Unique clicks on the Advertisement link My question is purely on the query and displaying of the Advertisement and nothing to do with the administration side. If there is ever money involved with my Advertisement buying/selling of adspace, then the stats need to be accurate and make sure people can't easily cheat the system. Is tracking IP address really the only way to try to prevent click fraud? I am hoping someone with some experience can clarify I am on the right track? As well as give me any advice, tips, or anything else I should know about doing something like this?

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• Batch file to uninstall all Sun Java versions?

  - by Ricket

  I'm setting up a system to keep Java in our office up to date. Everyone has all different versions of Java, many of them old and insecure, and some dating back as far as 1.4. I have a System Center Essentials server which can push out and silently run a .msi file, and I've already tested that it can install the latest Java. But old versions (such as 1.4) aren't removed by the installer, so I need to uninstall them. Everyone is running Windows XP. The neat coincidence is that Sun just got bought by Oracle and Oracle has now changed all the instances of "Sun" to "Oracle" in Java. So, I can conveniently not have to worry about uninstalling the latest Java, because I can just do a search and uninstall all Sun Java programs. I found the following batch script on a forum post which looked promising: @echo off & cls Rem List all Installation subkeys from uninstall key. echo Searching Registry for Java Installs for /f %%I in ('reg query HKLM\SOFTWARE\microsoft\windows\currentversion\uninstall') do echo %%I | find "{" > nul && call :All-Installations %%I echo Search Complete.. goto :EOF :All-Installations Rem Filter out all but the Sun Installations for /f "tokens=2*" %%T in ('reg query %1 /v Publisher 2^> nul') do echo %%U | find "Sun" > nul && call :Sun-Installations %1 goto :EOF :Sun-Installations Rem Filter out all but the Sun-Java Installations. Note the tilda + n, which drops all the subkeys from the path for /f "tokens=2*" %%T in ('reg query %1 /v DisplayName 2^> nul') do echo . Uninstalling - %%U: | find "Java" && call :Sun-Java-Installs %~n1 goto :EOF :Sun-Java-Installs Rem Run Uninstaller for the installation MsiExec.exe /x%1 /qb echo . Uninstall Complete, Resuming Search.. goto :EOF However, when I run the script, I get the following output: Searching Registry for Java Installs 'DEV_24x6' is not recognized as an internal or external command, operable program or batch file. 'SUBSYS_542214F1' is not recognized as an internal or external command, operable program or batch file. And then it appears to hang and I ctrl-c to stop it. Reading through the script, I don't understand everything, but I don't know why it is trying to run pieces of registry keys as programs. What is wrong with the batch script? How can I fix it, so that I can move on to somehow turning it into a MSI and deploying it to everyone to clean up this office? Or alternatively, can you suggest a better solution or existing MSI file to do what I need? I just want to make sure to get all the old versions of Java off of everyone's computers, since I've heard of exploits that cause web pages to load using old versions of Java and I want to avoid those.

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• IIS web service responds on server, not from remote client

  - by Aharon Manne

  I have installed a web service on a server running IIS (v6, as far as I can tell). There is another service installed, which responds as expected. My service responds correctly when a browser is pointed to localhost, but there is no response when a remote client tries to query the service. Fiddler on the remote client simply reports a timeout. Wireshark on the remote client shows no response at all from the server, no NACK, nothing. Wireshark on the server detects no query at the relevant port (the service is installed on port 8080). There are no relevant entries in the event viewer. Obviously there is some issue of permissions or authentication. I have tried to compare my service to the service that works, but I have not been able to locate relevant parameters. Any help would be greatly appreciated.

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• High Performance SQL Views Using WITH(NOLOCK)

  - by gt0084e1

  Every now and then you find a simple way to make everything much faster. We often find customers creating data warehouses or OLAP cubes even though they have a relatively small amount of data (a few gigs) compared to their server memory. If you have more server memory than the size of your database or working set, nearly any aggregate query should run in a second or less. In some situations there may be high traffic on from the transactional application and SQL server may wait for several other queries to run before giving you your results. The purpose of this is make sure you don’t get two versions of the truth. In an ATM system, you want to give the bank balance after the withdrawal, not before or you may get a very unhappy customer. So by default databases are rightly very conservative about this kind of thing. Unfortunately this split-second precision comes at a cost. The performance of the query may not be acceptable by today’s standards because the database has to maintain locks on the server. Fortunately, SQL Server gives you a simple way to ask for the current version of the data without the pending transactions. To better facilitate reporting, you can create a view that includes these directives. CREATE VIEW CategoriesAndProducts AS SELECT * FROM dbo.Categories WITH(NOLOCK) INNER JOIN dbo.Products WITH(NOLOCK) ON dbo.Categories.CategoryID = dbo.Products.CategoryID In some cases quires that are taking minutes end up taking seconds. Much easier than moving the data to a separate database and it’s still pretty much real time give or take a few milliseconds. You’ve been warned not to use this for bank balances though. More from Data Stream

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• Database Backup History From MSDB in a pivot table

  - by steveh99999

  I knocked up a nice little query to display backup history for each database in a pivot table format.I wanted to display the most recent full, differential, and transaction log backup for each database. Here's the SQL :-WITH backupCTE AS (SELECT name, recovery_model_desc, d AS 'Last Full Backup', i AS 'Last Differential Backup', l AS 'Last Tlog Backup' FROM ( SELECT db.name, db.recovery_model_desc,type, backup_finish_date FROM master.sys.databases db LEFT OUTER JOIN msdb.dbo.backupset a ON a.database_name = db.name WHERE db.state_desc = 'ONLINE' ) AS Sourcetable   PIVOT (MAX (backup_finish_date) FOR type IN (D,I,L) ) AS MostRecentBackup ) SELECT * FROM backupCTE Gives output such as this :-  With this query, I can then build up some straightforward queries to ensure backups are scheduled and running as expected -For example, the following logic can be used ;-  - WHERE [Last Full Backup] IS NULL) - ie database has never been backed up.. - WHERE [Last Tlog Backup] < DATEDIFF(mm,GETDATE(),-60) AND recovery_model_desc <> 'SIMPLE') - transction log not backed up in last 60 minutes. - WHERE [Last Full Backup] < DATEDIFF(dd,GETDATE(),-1) AND [Last Differential Backup] < [Last Full Backup]) -- no backup in last day.- WHERE [Last Differential Backup] < DATEDIFF(dd,GETDATE(),-1) AND [Last Full Backup] < DATEDIFF(dd,GETDATE(),-8) ) -- no differential backup in last day when last full backup is over 8 days old.   

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• Ping Unknown Host on CentOS at EC2

  - by organicveggie

  Weird problem. We have a collection of servers running CentOS 5 on EC2. The setup includes two DNS servers and two LDAP servers. DNS has a CNAME pointing at the primary LDAP server. One machine (and only one machine) is giving me problems. I can ssh into the server using LDAP authentication. But once I'm on the machine, ping won't resolve the LDAP host even though DNS seems to work fine. Here's ping: $ ping ldap.mycompany.ec2 ping: unknown host ldap.mycompany.ec2 Here's the output of dig: $ dig ldap.mycompany.ec2 ; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_5.3 <<>> ldap.studyblue.ec2 ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2893 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;ldap.mycompany.ec2. IN A ;; ANSWER SECTION: ldap.mycompany.ec2. 3600 IN CNAME ec2-hostname.compute-1.amazonaws.com. ec2-hostname.compute-1.amazonaws.com. 55 IN A aaa.bbb.ccc.ddd ;; Query time: 12 msec ;; SERVER: 10.32.159.xxx#53(10.32.159.xxx) ;; WHEN: Tue May 31 11:16:30 2011 ;; MSG SIZE rcvd: 107 And here is resolv.conf: $ cat /etc/resolv.conf search mycompany.ec2 nameserver 10.32.159.xxx nameserver 10.244.19.yyy And here is my hosts file: $ cat /etc/hosts 10.122.15.zzz bamboo4 bamboo4.mycompany.ec2 127.0.0.1 localhost localhost.localdomain And here's nsswitch.conf $ cat /etc/nsswitch.conf passwd: files ldap shadow: files ldap group: files ldap sudoers: ldap files hosts: files dns bootparams: nisplus [NOTFOUND=return] files ethers: files netmasks: files networks: files protocols: files rpc: files services: files netgroup: files ldap publickey: nisplus automount: files ldap aliases: files nisplus So DNS works the way I would expect. And I can ping the ldap server by ip address. And I can even access the box with SSH using LDAP authentication. Any suggestions?

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• Hired developer insists on doing things the wrong way

  - by Tariq- iPHONE Programmer

  Hello, i am working with Social Networking iphone app which require remote data connection. So i hired a php developer in order to provide me RESTful services. But when i start working with him, he arguing me that he will not make stored procedures and web services. Instead of he suggested me to pass query as a parameter. Suppose If I have to call Search service, he told me to send POST request with 3 parameters: Query="select * from users", username=abd and password = 123 And i thing there is no such architecture in order to use remote data. Then he is saying it is possible through socket programming. And I am 100% sure this is not an appropriate way to access remote data. This is simply illogical. Thousands of iphone application using REST/SOAP services to make remote data connection He just declined me to provide RESTful services. Please its my heartily advice to all developers that post your own views over here. So that I can show to that developers that these are the views from all developers worldwide.

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• Observing flow control idle time in TCP

  - by user12820842

  Previously I described how to observe congestion control strategies during transmission, and here I talked about TCP's sliding window approach for handling flow control on the receive side. A neat trick would now be to put the pieces together and ask the following question - how often is TCP transmission blocked by congestion control (send-side flow control) versus a zero-sized send window (which is the receiver saying it cannot process any more data)? So in effect we are asking whether the size of the receive window of the peer or the congestion control strategy may be sub-optimal. The result of such a problem would be that we have TCP data that we could be transmitting but we are not, potentially effecting throughput. So flow control is in effect: when the congestion window is less than or equal to the amount of bytes outstanding on the connection. We can derive this from args[3]-tcps_snxt - args[3]-tcps_suna, i.e. the difference between the next sequence number to send and the lowest unacknowledged sequence number; and when the window in the TCP segment received is advertised as 0 We time from these events until we send new data (i.e. args[4]-tcp_seq = snxt value when window closes. Here's the script: #!/usr/sbin/dtrace -s #pragma D option quiet tcp:::send / (args[3]-tcps_snxt - args[3]-tcps_suna) = args[3]-tcps_cwnd / { cwndclosed[args[1]-cs_cid] = timestamp; cwndsnxt[args[1]-cs_cid] = args[3]-tcps_snxt; @numclosed["cwnd", args[2]-ip_daddr, args[4]-tcp_dport] = count(); } tcp:::send / cwndclosed[args[1]-cs_cid] && args[4]-tcp_seq = cwndsnxt[args[1]-cs_cid] / { @meantimeclosed["cwnd", args[2]-ip_daddr, args[4]-tcp_dport] = avg(timestamp - cwndclosed[args[1]-cs_cid]); @stddevtimeclosed["cwnd", args[2]-ip_daddr, args[4]-tcp_dport] = stddev(timestamp - cwndclosed[args[1]-cs_cid]); @numclosed["cwnd", args[2]-ip_daddr, args[4]-tcp_dport] = count(); cwndclosed[args[1]-cs_cid] = 0; cwndsnxt[args[1]-cs_cid] = 0; } tcp:::receive / args[4]-tcp_window == 0 && (args[4]-tcp_flags & (TH_SYN|TH_RST|TH_FIN)) == 0 / { swndclosed[args[1]-cs_cid] = timestamp; swndsnxt[args[1]-cs_cid] = args[3]-tcps_snxt; @numclosed["swnd", args[2]-ip_saddr, args[4]-tcp_dport] = count(); } tcp:::send / swndclosed[args[1]-cs_cid] && args[4]-tcp_seq = swndsnxt[args[1]-cs_cid] / { @meantimeclosed["swnd", args[2]-ip_daddr, args[4]-tcp_sport] = avg(timestamp - swndclosed[args[1]-cs_cid]); @stddevtimeclosed["swnd", args[2]-ip_daddr, args[4]-tcp_sport] = stddev(timestamp - swndclosed[args[1]-cs_cid]); swndclosed[args[1]-cs_cid] = 0; swndsnxt[args[1]-cs_cid] = 0; } END { printf("%-6s %-20s %-8s %-25s %-8s %-8s\n", "Window", "Remote host", "Port", "TCP Avg WndClosed(ns)", "StdDev", "Num"); printa("%-6s %-20s %-8d %@-25d %@-8d %@-8d\n", @meantimeclosed, @stddevtimeclosed, @numclosed); } So this script will show us whether the peer's receive window size is preventing flow ("swnd" events) or whether congestion control is limiting flow ("cwnd" events). As an example I traced on a server with a large file transfer in progress via a webserver and with an active ssh connection running "find / -depth -print". Here is the output: ^C Window Remote host Port TCP Avg WndClosed(ns) StdDev Num cwnd 10.175.96.92 80 86064329 77311705 125 cwnd 10.175.96.92 22 122068522 151039669 81 So we see in this case, the congestion window closes 125 times for port 80 connections and 81 times for ssh. The average time the window is closed is 0.086sec for port 80 and 0.12sec for port 22. So if you wish to change congestion control algorithm in Oracle Solaris 11, a useful step may be to see if congestion really is an issue on your network. Scripts like the one posted above can help assess this, but it's worth reiterating that if congestion control is occuring, that's not necessarily a problem that needs fixing. Recall that congestion control is about controlling flow to prevent large-scale drops, so looking at congestion events in isolation doesn't tell us the whole story. For example, are we seeing more congestion events with one control algorithm, but more drops/retransmission with another? As always, it's best to start with measures of throughput and latency before arriving at a specific hypothesis such as "my congestion control algorithm is sub-optimal".

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• Javascript MVC in principle

  - by Michael

  Suppose I want to implement MVC in JavaScript. I am not asking about MVC frameworks. I am asking how to build it in principle. Let's consider a search page of an e-commerce site, which works s follows: User chooses a product and its attributes and press a "search" button. Application sends the search request to the server, receives a list of products. Application displays the list in the web page. I think the Model holds a Query and list of Product objects and "publishes" such events as "query updated", "list of products updated", etc. The Model is not aware of DOM and server, or course. View holds the entire DOM tree and "subscribes" to the Model events to update the DOM. Besides, it "publishes" such events as "user chose a product", "user pressed the search button" etc. Controller does not hold any data. It "subscribes" to the View events, calls the server and updates the Model. Does it make sense?

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• Algorithmic problem - quickly finding all #'s where value %x is some given value

  - by Steve B.

  Problem I'm trying to solve, apologies in advance for the length: Given a large number of stored records, each with a unique (String) field S. I'd like to be able to find through an indexed query all records where Hash(S) % N == K for any arbitrary N, K (e.g. given a million strings, find all strings where HashCode(s) % 17 = 5. Is there some way of memoizing this so that we can quickly answer any question of this form without doing the % on every value? The motivation for this is a system of N distributed nodes, where each record has to be assigned to at least one node. The nodes are numbered 0 - (K-1) , and each node has to load up all of the records that match it's number: If we have 3 nodes Node 0 loads all records where Hash % 3 ==0 Node 1 loads all records where Hash % 3 ==1 Node 2 loads all records where Hash % 3 ==2 adding a 4th node, obviously all the assignments have to be recomputed - Node 0 loads all records where Hash % 4 ==0 ... etc I'd like to easily find these records through an indexed query without having to compute the mod individually. The best I've been able to come up with so far: If we take the prime factors of N (p1 * p2 * ... ) if N % M == I then p % M == I % p for all of N's prime factors e.g. 10 nodes : N % 10 == 6 then N % 2 = 0 == 6 %2 N % 5 = 1 == 6 %5 so storing an array of the "%" of N for the first "reasonable" number of primes for my data set should be helpful. For example in the above example we store the hash and the primes HASH PRIMES (array of %2, %3, %5, %7, ... ]) 16 [0 1 1 2 .. ] so looking for N%10 == 6 is equivalent to looking for all values where array[1]==1 and array[2] == 1. However, this breaks at the first prime larger than the highest number I'm storing in the factor table. Is there a better way?

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• Windows Event Viewer - XML Custom Filter

  - by Frank

  <QueryList> <Query Id="0" Path="Application"> <Select Path="Application"> *[EventData[Data and (Data="Error")]] </Select> </Query> </QueryList> I believe the above XML custom filter would work if I wanted to check for Events where "Data" equals the word "Error". However, what I want to express is that I want the Events where Data CONTAINS the word "Error" . . . how do I express that? I've Goggled around, but I can find no references to Regular Expression like pattern matching in the Event Viewer. XPath has "contains", but if Event Viewer will support it, I cannot seem to figure out the syntax for invoking it.

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• Best design for a "Command Executer" class

  - by Justin984

  Sorry for the vague title, I couldn't think of a way to condense the question. I am building an application that will run as a background service and intermittently collect data about the system its running on. A second Android controller application will query the system over tcp/ip for statistics about the system. Currently, the background service has a tcp listener class that reads/writes bytes from a socket. When data is received, it raises an event to notify the service. The service takes the bytes, feeds them into a command parser to figure out what is being requested, and then passes the parsed command to a command executer class. When the service receives a "query statistics" command, it should return statistics over the tcp/ip connection. Currently, all of these classes are fully decoupled from each other. But in order for the command executer to return statistics, it will obviously need access to the socket somehow. For reasons I can't completely articulate, it feels wrong for the command executer to have a direct reference to the socket. I'm looking for strategies and/or design patterns I can use to return data over the socket while keeping the classes decoupled, if this is possible. Hopefully this makes sense, please let me know if I can include any info that would make the question easier to understand.

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• Construction Paper, Legos, and Architectural Modeling

  I can remember as a kid playing with construction paper and Legos to explore my imagination. Through my exploration I was able to build airplanes, footballs, guns, and more, out of paper. Additionally I could create entire cities, robots, or anything else I could image out of Legos.  These toys, I now realize were in fact tools that gave me an opportunity to explore my ideas in the physical world through the use of modeling.  My imagination was allowed to run wild as I, unknowingly at the time, made design decisions that directly affected the models I was building from the raw materials.  To prove my point further, I can remember building a paper airplane that seemed to go nowhere when I tried to throw it. So I decided to attach a paper clip to the plane before I decided to throw it the next time to test my concept that by adding more weight to the plane that it would fly better and for longer distances. The paper airplane allowed me to model my design decision through the use of creating an artifact in that I created a paper airplane that was carrying extra weight through the incorporation of the paper clip in to the design. Also, I remember using Legos to build all sorts of creations, and these creations became artifacts of my imagination. As I further and further defined my Lego creations through the process of playing I was able to create elaborate artifacts of my imagination. These artifacts represented design decision I had made in the evolution of my creation through my child like design process. In some form or fashion the artifacts I created as a kid are very similar to the artifacts that I create when I model a software architectural concept or a software design in that the process of making decisions is directly translated in to a tangible model in the form of an architectural model. Architectural models have been defined as artifacts that depict design decisions of a system’s architecture.  The act of creating architectural models is the act of architectural modeling. Furthermore, architectural modeling is the process of creating a physical model based architectural concepts and documenting these design decisions. In the process of creating models, the standard notation used is Architectural modeling notation. This notation is the primary method of capturing the essence of design decisions regarding architecture.  Modeling notations can vary based on the need and intent of a project; typically they range from natural language to a diagram based notation. Currently, Unified Markup Language (UML) is the industry standard in terms of architectural modeling notation  because allows for architectures to be defined through a series of boxes, lines, arrows and other basic symbols that encapsulate design designs in to virtual components, connectors, configurations and interfaces.  Furthermore UML allows for additional break down of models through the use of natural language as to explain each section of the model in plain English. One of the major factors in architectural modeling is to define what is to be modeled. As a basic rule of thumb, I tend to model architecture based on the complexity of systems or sub sub-systems of architecture. Another key factor is the level of detail that is actually needed for a model. For example if I am modeling a system for a CEO to view then the low level details will be omitted. In comparison, if I was modeling a system for another engineer to actually implement I would include as much detailed information as I could to help the engineer implement my design.

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• Bind dns server in Solaris 10 and win xp clients

  - by stevecomptech

  Hi, Added this in zone db file, i am running solaris 10 _ldap._tcp.mydomain.com. SRV 0 0 389 dc.mydomain.com. _kerberos._tcp.mydomain.com. SRV 0 0 88 dc.mydomain.com. _ldap._tcp.dc._msdcs.mydomain.com. SRV 0 0 389 dc.mydomain.com. _kerberos._tcp.dc._msdcs.mydomain.com. SRV 0 0 88 host.mydomain.com. Now i get this error when i try to join win xp to the domain The query was for the SRV record for _ldap._tcp.dc._msdcs.mydomain.com The following domain controllers were identified by the query: host.mydomain.com Common causes of this error include: Host (A) records that map the name of the domain controller to its IP addresses are missing or contain incorrect addresses. Domain controllers registered in DNS are not connected to the network or are not running. What do i need to change in order my win xp join the domain

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• SOA Composite Sensors : Good Practice

  - by angelo.santagata

  I was discussing a interesting design problem with a colleague of mine Niall (his blog) on the topic of how to cancel an inflight SOA Composite process.  Obviously one way to do this is to cancel the process from enterprise Manager ( http://hostort/em ) , however we were thinking this isnt a “user friendly” way of doing this.. If you look at Nialls blog you’ll see he’s highlighted a number of different APIs which enable you the ability to manipulate the SCA instance, e.g. Code Snippet to purge (delete) an instance How to determine the instanceId from a composite_sensor_value using the “composite_sensor_value” table How to determine a BPEL Process status using the cube_instance table   Now all of these require that you know the instanceId of your SOA Composite, how does one find this out? Well the easiest way of doing this is to create a composite sensor on the SCA component. A composite sensor is simply a way of publishing a piece of business data as part of your composite. The magic here is that you can later query composites based on this value. So a good best practice is that for any composites you create consider publishing a composite sensor value using a primary key of some sort , e.g. orderId, that way if you need to manipulate/query composites you can easily look up the instanceId using the sensorid.   For information on how to create a composite Sensor id see this documentation link  

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• Why don't DNS root servers answer?

  - by JustTrying

  If I try to query a root server with dig, I never receive an answer. For example the output for dig @b.root-servers.net www.ubuntu.com is ; << DiG 9.8.1-P1 << @b.root-servers.net www.ubuntu.com ; (1 server found) ;; global options: +cmd ;; connection timed out; no servers could be reached But if I query other servers (the one of my ISP, or 8.8.8.8), they answer correctly. Why?

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• 12c - Invisible Columns...

  - by noreply(at)blogger.com (Thomas Kyte)

  Remember when 11g first came out and we had "invisible indexes"?  It seemed like a confusing feature - indexes that would be maintained by modifications (hence slowing them down), but would not be used by queries (hence never speeding them up).  But - after you looked at them a while, you could see how they can be useful.  For example - to add an index in a running production system, an index used by the next version of the code to be introduced later that week - but not tested against the queries in version one of the application in place now.  We all know that when you add an index - one of three things can happen - a given query will go much faster, it won't affect a given query at all, or... It will make some untested query go much much slower than it used to.  So - invisible indexes allowed us to modify the schema in a 'safe' manner - hiding the change until we were ready for it.Invisible columns accomplish the same thing - the ability to introduce a change while minimizing any negative side effects of that change.  Normally when you add a column to a table - any program with a SELECT * would start seeing that column, and programs with an INSERT INTO T VALUES (...) would pretty much immediately break (an INSERT without a list of columns in it).  Now we can add a column to a table in an invisible fashion, the column will not show up in a DESCRIBE command in SQL*Plus, it will not be returned with a SELECT *, it will not be considered in an INSERT INTO T VALUES statement.  It can be accessed by any query that asks for it, it can be populated by an INSERT statement that references it, but you won't see it otherwise.For example, let's start with a simple two column table:ops$tkyte%ORA12CR1> create table t  2  ( x int,  3    y int  4  )  5  /Table created.ops$tkyte%ORA12CR1> insert into t values ( 1, 2 );1 row created.Now, we will add an invisible column to it:ops$tkyte%ORA12CR1> alter table t add                     ( z int INVISIBLE );Table altered.Notice that a DESCRIBE will not show us this column:ops$tkyte%ORA12CR1> desc t Name              Null?    Type ----------------- -------- ------------ X                          NUMBER(38) Y                          NUMBER(38)and existing inserts are unaffected by it:ops$tkyte%ORA12CR1> insert into t values ( 3, 4 );1 row created.A SELECT * won't see it either:ops$tkyte%ORA12CR1> select * from t;         X          Y---------- ----------         1          2         3          4But we have full access to it (in well written programs! The ones that use a column list in the insert and select - never relying on "defaults":ops$tkyte%ORA12CR1> insert into t (x,y,z)                         values ( 5,6,7 );1 row created.ops$tkyte%ORA12CR1> select x, y, z from t;         X          Y          Z---------- ---------- ----------         1          2         3          4         5          6          7and when we are sure that we are ready to go with this column, we can just modify it:ops$tkyte%ORA12CR1> alter table t modify z visible;Table altered.ops$tkyte%ORA12CR1> select * from t;         X          Y          Z---------- ---------- ----------         1          2         3          4         5          6          7I will say that a better approach to this - one that is available in 11gR2 and above - would be to use editioning views (part of Edition Based Redefinition - EBR ).  I would rather use EBR over this approach, but in an environment where EBR is not being used, or the editioning views are not in place, this will achieve much the same.Read these for information on EBR:http://www.oracle.com/technetwork/issue-archive/2010/10-jan/o10asktom-172777.htmlhttp://www.oracle.com/technetwork/issue-archive/2010/10-mar/o20asktom-098897.htmlhttp://www.oracle.com/technetwork/issue-archive/2010/10-may/o30asktom-082672.html

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