Search Results

Search found 40870 results on 1635 pages for 'database design'.

Page 18/1635 | < Previous Page | 14 15 16 17 18 19 20 21 22 23 24 25  | Next Page >

  • Recover mysql database - mysqldump gives "table <tablename> doesn't exist (1146)"

    - by Matthew
    Backstory Ubuntu died (wouldn't boot) and I couldn't fix it. I booted a live cd to recover the important stuff and saved it to my NAS. One of the things I backed up was /var/lib/mysql. Reinstalled with Linux Mint because I was on Ubuntu 10.0.4 this was a good opportunity to try a new distro (and I don't like Unity). Now I want to recover my old mediawiki, so I shut down mysql daemon, cp -R /media/NAS/Backup/mysql/mediawiki@002d1_19_1 /var/lib/mysql/, set file ownership and permissions correctly, and start mysql back up. Problem Now I'm trying to export the database so I can restore the database, but when I execute the mysqldump I get an error: $ mysqldump -u mediawikiuser -p mediawiki-1_19_1 -c | gzip -9 > wiki.2012-11-15.sql.gz Enter password: mysqldump: Got error: 1146: Table 'mediawiki-1_19_1.archive' doesn't exist when using LOCK TABLES Things I've tried I tried using --skip-lock-tables but I get this: Error: Couldn't read status information for table archive () mysqldump: Couldn't execute 'show create table `archive`': Table 'mediawiki-1_19_1.archive' doesn't exist (1146) I tried logging in to mysql and I can list the tables that should be there, but trying to describe or select from them errors out the same way as the dump: mysql> show tables; +----------------------------+ | Tables_in_mediawiki-1_19_1 | +----------------------------+ | archive | | category | | categorylinks | ... | user_properties | | valid_tag | | watchlist | +----------------------------+ 49 rows in set (0.00 sec) mysql> describe archive; ERROR 1146 (42S02): Table 'mediawiki-1_19_1.archive' doesn't exist I believe mediawiki was installed using innodb and binary data. Am I screwed or is there a way to recover this?

    Read the article

  • Database types for customer analytics

    - by Drewdavid
    I am exploring a paid solution to start providing better embedded, dashboard-style analytics information to our website customers/account holders, but would like to also offer an in-house development option to our team. The more equipped I am with specifics (such as the subject of this question), the better the adoption rate from the team (or so I have found), regardless of the path we choose Would anyone care to summarize a couple of options for a fast and scalable database type through which we would provide the following: • Daily pageviews to a users account pages (users have between 1 and 1000 pages) • Some calculated/compounded metrics (such as conversion rate, i.e. certain page type viewed to contact form thank you page ratio) • We have about 1,500 members (will need room to grow); the number of concurrently logged in users will for the question's sake be 50 I ask because our developer has balked at providing this level of "over time" granularity (i.e. daily) due to the number of space it would take up in a MYSQL database To avoid a downvote I have asked specifically for more than one option, realizing that different people will have different solutions. I will make amendments to my question if so guided by answering parties Thank you for sharing your valued answers :)

    Read the article

  • Implementation details of database synchronisation API

    - by Daniel
    I want to achieve a database synchronisation between my server database and a client application. The server would run MySQL and the applications may run different database technologies, their implementation isn't important. I have a MySQL database online and web accessible via an API I wrote in PHP (just a detail). My client application ships with a copy of the online data. As time passes my goal is to check for any changes in the online database and make these updates available to the client app via an API call, by sending a date to an API endpoint corresponding to the last date the app was updated, the response would be a JSON filled with all new objects and updated objects, and delete IDs, this makes possible to update the local store appropriately. Essentially I want to do this: http://dbconvert.com/synchronization.php My question is about the implementation details. Would I need to add a column to my database tables with a "last modified" date? Since the client app could be very out of date if it's been offline for a long time, does that also mean I shouldn't delete data from the online database but instead have another column called "delete" set to 1 and a modified date updated appropriately? Would my SQL query simply check for all data with a modified date superior then the date passed into the API request by the client? I feel like there's a lot more to it then having a ton of dates everywhere. And also, worry that I will need to persist a lot of old data in order to ensure that old versions of the client app always have the opportunity to delete parts of their data when they are able to sync.

    Read the article

  • Oracle Database 12c is Generally Available

    - by Thanos
    Oracle Database 12c, a major release of Oracle’s flagship product, is generally available as of 25 June 2013. Oracle Database 12c introduces a breakthrough, new multitenant architecture enabling customers to create multiple, pluggable databases for database consolidation and cloud deployments. Customers will realize greater efficiency and flexibility through innovations such as Oracle Multitenant option and Automatic Data Optimization with Heat Map, for compressing and tiering data at a higher density. These unique advancements, combined with major enhancements in availability, security, and big data support, make Oracle Database 12c the ideal platform for private and public cloud deployments. As of 25/06/2013, the product is available for download on Linux x86-64, Solaris Sparc64 and Solaris (x86-64) via Oracle Technology Network. A news release is planned for July 1st, and an external launch webcast, Plug into the Cloud with Oracle Database 12c, featuring Mark Hurd, Andy Mendelsohn, Tom Kyte and other experts is planned for July 10th. Open here in New Window Everybody can register for the launch webcast here and register to attend global in-person events here. Resources: www.oracle.com/database www.oracle.com/databaseoptions Oracle Partner Network Database Knowledge Zone Open in Google Docs Viewer Open link in new tab Open link in new window Open link in new incognito window Download file Copy link address Edit PDF File on PDFescape.com

    Read the article

  • Enterprise Manager Database Control Configuration - Recovering From Errors Due to CA Expiry on Oracle Database 10.2.0.4 or 10.2.0.5 from 31-Dec-2010 onwards

    - by jayatheertha.rao(at)oracle.com
    Description What is the Issue? In Enterprise Manager Database Control with Oracle Database 10.2.0.4 and 10.2.0.5, the root certificate used to secure communications via the Secure Socket Layer (SSL) protocol will expire on 31-Dec-2010 00:00:00. The certificate expiration will cause errors if you attempt to configure Database Control on or after 31-Dec-2010. Existing Database Control configurations are not affected by this issue. Likelihood of Occurrence What Versions Are Affected? The issue impacts configuration of Database Control with Oracle Database 10.2.0.4 and 10.2.0.5 only. It does not impact database creation or upgrade. The issue does not impact existing Database Control configurations. What Happens During Database Control Configuration Failure? Database Configuration Assistant (DBCA) and Database Upgrade Assistant (DBUA) Errors Database Configuration Assistant (DBCA) and Database Upgrade Assistant (DBUA) will report the following error in the console: Could not complete the Enterprise Manager configuration.Enterprise manager configuration failed due to the following error -Error starting Database Control Enterprise Manager Configuration Assistant (EMCA) Errors Enterprise Manager Configuration Assistant (EMCA) will write errors similar to those below to the emca.log file: CONFIG: Securing Database Control completed successfully .Jan 2, 2011 7:22:47 PM oracle.sysman.emcp.ParamsManager getParamCONFIG: No value was set for the parameter ORACLE_HOSTNAME.Jan 2, 2011 7:22:47 PM oracle.sysman.emcp.util.DBControlUtil startOMSINFO: Starting Database Control (this may take a while) ...Jan 2, 2011 7:22:47 PM oracle.sysman.emcp.util.PlatformInterface addEnvVarToListCONFIG: Value for env var 'ORACLE_HOSTNAME' is '', discarding the sameCONFIG: Returning env array from cacheJan 2, 2011 7:22:47 PM oracle.sysman.emcp.util.PlatformInterface executeCommandCONFIG: Starting execution: /myhost/bin/emctl start dbconsoleJan 2, 2011 7:27:26 PM oracle.sysman.emcp.util.PlatformInterface executeCommandCONFIG: Exit value of 1Jan 2, 2011 7:27:26 PM oracle.sysman.emcp.util.PlatformInterface executeCommandCONFIG: Oracle Enterprise Manager 10g Database Control Release 10.2.0.4.0Copyright (c) 1996, 2007 Oracle Corporation. All rights reserved.https://myhost:5501/em/console/aboutApplicationStarting Oracle Enterprise Manager 10g Database Control............................................................................................. failed.------------------------------------------------------------------Logs are generated in directory /myhost/sysman/logJan 2, 2011 7:27:26 PM oracle.sysman.emcp.util.PlatformInterface executeCommandWARNING: Error executing /myhost/bin/emctl start dbconsoleJan 2, 2011 7:27:26 PM oracle.sysman.emcp.EMConfig performSEVERE: Error starting Database ControlRefer to the log file at /myhost/dbua/d4/upgrade/emConfig.log for more details.Jan 2, 2011 7:27:26 PM oracle.sysman.emcp.EMConfig performCONFIG: Stack Trace:oracle.sysman.emcp.exception.EMConfigException: Error starting Database Controlat oracle.sysman.emcp.EMDBPostConfig.performUpgrade(EMDBPostConfig.java:763)at oracle.sysman.emcp.EMDBPostConfig.invoke(EMDBPostConfig.java:232)at oracle.sysman.emcp.EMDBPostConfig.invoke(EMDBPostConfig.java:193)at oracle.sysman.emcp.EMConfig.perform(EMConfig.java:184)at oracle.sysman.assistants.util.em.EMConfiguration.run(EMConfiguration.java:436)at oracle.sysman.assistants.util.em.EMConfigStep.executeImpl(EMConfigStep.java:140)at oracle.sysman.assistants.util.step.BasicStep.execute(BasicStep.java:210)at oracle.sysman.assistants.util.step.BasicStep.callStep(BasicStep.java:251)at oracle.sysman.assistants.dbma.backend.EMConfigStep.executeStepImpl(EMConfigStep.java:104)at oracle.sysman.assistants.dbma.backend.SummarizableStep.executeImpl(SummarizableStep.java:175)at oracle.sysman.assistants.util.step.BasicStep.execute(BasicStep.java:210)at oracle.sysman.assistants.util.step.Step.execute(Step.java:140)at oracle.sysman.assistants.util.step.StepContext$ModeRunner.run(StepContext.java:2488)at java.lang.Thread.run(Thread.java:534) The EMCA console will display output similar to the following: aime@myhost09 db_1]$ bin/emca -config dbcontrol db -repos recreate -clusterSTARTED EMCA at Jan 11, 2011 4:11:01 PMEM Configuration Assistant, Version 10.2.0.1.0 ProductionCopyright (c) 2003, 2005, Oracle. All rights reserved.Enter the following information:Database unique name: catestDatabase Control is already configured for the database catestYou have chosen to configure Database Control for managing the database catestThis will remove the existing configuration and the default settings and perform a fresh configurationDo you wish to continue? [yes(Y)/no(N)]: YListener port number: 1521Cluster name: myclusterPassword for SYS user:Password for DBSNMP user:Password for SYSMAN user:Email address for notifications (optional):Outgoing Mail (SMTP) server for notifications (optional):........Jan 11, 2011 4:18:05 PM oracle.sysman.emcp.util.DBControlUtil secureDBConsoleINFO: Securing Database Control (this may take a while) ...Jan 11, 2011 4:19:31 PM oracle.sysman.emcp.util.DBControlUtil startOMSINFO: Starting Database Control (this may take a while) ...Jan 11, 2011 4:28:38 PM oracle.sysman.emcp.EMConfig performSEVERE: Error starting Database ControlRefer to the log file at /myhost/oracle/product/10.2.0/db_1/cfgtoollogs/emca/catest/emca_2011-01-11_04-11-01-PM.log for more details.Could not complete the configuration. Refer to the log file at /myhost/oracle/product/10.2.0/db_1/cfgtoollogs/emca/catest/emca_2011-01-11_04-11-01-PM.log for more details. At the end of the database installation on non-Windows platforms, both Database Control and the Management Agent will be up and running, even though the status of both components will be shown as not running, because EMCTL will be unable to connect to the dbconsole process. In addition, Database Control will fail to connect to the Agent. Note for Windows Platform Only:On Windows, the dbconsole process will be stopped after the failed configuration attempt. Note that the tool used to perform Database Control configuration (DBUA, DBCA or EMCA) will also wait for 15 minutes for Database Control to start, then time out. The output of the "emctl status dbconsole" command incorrectly returns the status of Database Control, as shown below: $ ./emctl status dbconsoleOracle Enterprise Manager 10g Database Control Release 10.2.0.1.0Copyright (c) 1996, 2005 Oracle Corporation. All rights reserved.https://myhost:1158/em/console/aboutApplicationOracle Enterprise Manager 10g is not running. The output of the "emctl status agent" command incorrectly returns the status of the Agent, as shownbelow: $ ./emctl status agentOracle Enterprise Manager 10g Database Control Release 10.2.0.1.0Copyright (c) 1996, 2005 Oracle Corporation. All rights reserved.---------------------------------------------------------------Agent is Not Running   For Solution, refer to Note: 1222603.1 Note: 1217493.1

    Read the article

  • SSIS Design Pattern: Loading Variable-Length Rows

    - by andyleonard
    Introduction I encounter flat file sources with variable-length rows on occassion. Here, I supply one SSIS Design Pattern for loading them. What's a Variable-Length Row Flat File? Great question - let's start with a definition. A variable-length row flat file is a text source of some flavor - comma-separated values (CSV), tab-delimited file (TDF), or even fixed-length, positional-, or ordinal-based (where the location of the data on the row defines its field). The major difference between a "normal"...(read more)

    Read the article

  • The right way to start out in game development/design [closed]

    - by Marco Sacristão
    Greetings everyone I'm a 19 year old student looking for some help in the field of game development. This question may or may not seem a bit overused, but the fact is that game development has been my life long dream, and after several hours of search I've realized that I've been going in circles for the past three or four months whilst doing such research on how to really get down and dirty with game development, therefor I decided to ask you guys if you could help me out at all. Let me start off with some information about me and things i've already learned about GameDev which might help you out on helping me out (wordplay!): I'm not an expert programmer, but I do have knowledge on how to program in several languages including C and Java (Currently learning Java in my degree in Computer Engineering), but my methodology might not be most correct in terms of syntax (hence my difficulty in starting out, i'm afraid that the starting point might not be the most correct, and it would deploy a wrongful development methodology that would be to corrected later on, in terms of game development or other projects). I have yet to work in a project as large as a game, never in my learning curve of programming I've done a project to the scale of a video game, only very small software (PHP Front-ends and Back-ends, with some basic JQuery and CSS knowledge). I'm not the biggest mathematician or physicist, but I already know that is not a problem, because there are several game engines already available for use and integration with home-made projects (Box2D, etc). I've also learned about some libraries that could be included in said projects, to ease out some process in game development, like SDL for example. I do not know how sprites, states, particles or any specific game-related techniques work. With that being said, you can see that I have some ideas on game development, but I have absolutely no clue on how to design and produce a game, or even how game-like mechanics work. It does not have to be a complex game just to start out, I'd rather learn the basic of game design (Like 2D drawing, tiling, object collision) and test that out in a language that I feel comfortable in which could be later on migrated to other platforms, as long that what I've learned is the correct way to do things, and not just something that I've learned from some guy on Youtube by replicating that code on the video. I'm sorry if my question is not in the best format possible, but I've got so many questions on my mind that are still un-answered that I don't know were to start! Thank you for reading.

    Read the article

  • how to evaluate own project

    - by gruszczy
    I am working on a open source project in pure C, that I have started some time ago, but only recently found time to add some features. I can clearly some weaknesses of my old design, so I am trying to refactor my old code. I have no idea however, how to evaluate properly my new code. Do you know about any techniques or tools for code evaluation? I am pretty good with object oriented design, but for about three years I had no contact with purely structural one. Therefore I don't have enough experience, to be able to discern between good and bad design choices.

    Read the article

  • 5 Mac Applications For Web And Graphic Design

    - by Jyoti
    In this article free applications useful and effective for the development and creation of websites with your Mac computer. Without further ado, here are 5 Excellent Mac Application for Web and Graphic Design. Fotoflexer : Fotoflexer claims to be “The world’s most advanced online image editor”. It offers completely free access to numerous features such as [...]

    Read the article

  • Rule of thumb for enemy art design in 2D platformer

    - by Terrance
    I'm at the early stages of developing a 2D side scrolling open ended platformer (think Metroidvania) and am having a bit of difficulty at enemy design inspiration for something of a scifi, nature, fantasy setting that isn't overly familar or obvious. I haven't seen too many articles, blogs or books that talk about the subject at great length. Is there a fair rule of thumb when coming up with enemy art with respect to keeping your player engaged?

    Read the article

  • Designing persistence schema for BigTable on AppEngine

    - by Vitalij Zadneprovskij
    I have tried to design the datastore schema for a very small application. That schema would have been very simple, if not trivial, using a relational database with foreign keys, many-to-many relations, joins, etc. But the problem was that my application was targeted for Google App Engine and I had to design for a database that was not relational. At the end I gave up. Is there a book or an article that describes design principles for applications that are meant for such databases? The books that I have found are about programming for App Engine and they don't spend many words about database design principles.

    Read the article

  • Why is permadeath essential to a roguelike design?

    - by Gregory Weir
    Roguelikes and roguelike-likes (Spelunky, The Binding of Isaac) tend to share a number of game design elements: Procedurally generated worlds Character growth by way of new abilities and powers Permanent death I can understand why starting with permadeath as a premise would lead you to the other ideas: if you're going to be starting over a lot, you'll want variety in your experiences. But why do the first two elements imply a permadeath approach?

    Read the article

  • How does I/O work for large graph databases?

    - by tjb1982
    I should preface this by saying that I'm mostly a front end web developer, trained as a musician, but over the past few years I've been getting more and more into computer science. So one idea I have as a fun toy project to learn about data structures and C programming was to design and implement my own very simple database that would manage an adjacency list of posts. I don't want SQL (maybe I'll do my own query language? I'm just having fun). It should support ACID. It should be capable of storing 1TB let's say. So with that, I was trying to think of how a database even stores data, without regard to data structures necessarily. I'm working on linux, and I've read that in that world "everything is a file," including hardware (like /dev/*), so I think that that obviously has to apply to a database, too, and it clearly does--whether it's MySQL or PostgreSQL or Neo4j, the database itself is a collection of files you can see in the filesystem. That said, there would come a point in scale where loading the entire database into primary memory just wouldn't work, so it doesn't make sense to design it with that mindset (I assume). However, reading from secondary memory would be much slower and regardless some portion of the database has to be in primary memory in order for you to be able to do anything with it. I read this post: Why use a database instead of just saving your data to disk? And I found it difficult to understand how other databases, like SQLite or Neo4j, read and write from secondary memory and are still very fast (faster, it would seem, than simply writing files to the filesystem as the above question suggests). It seems the key is indexing. But even indexes need to be stored in secondary memory. They are inherently smaller than the database itself, but indexes in a very large database might be prohibitively large, too. So my question is how is I/O generally done with large databases like the one I described above that would be at least 1TB storing a big adjacency list? If indexing is more or less the answer, how exactly does indexing work--what data structures should be involved?

    Read the article

  • Removing hard-coded values and defensive design vs YAGNI

    - by Ben Scott
    First a bit of background. I'm coding a lookup from Age - Rate. There are 7 age brackets so the lookup table is 3 columns (From|To|Rate) with 7 rows. The values rarely change - they are legislated rates (first and third columns) that have stayed the same for 3 years. I figured that the easiest way to store this table without hard-coding it is in the database in a global configuration table, as a single text value containing a CSV (so "65,69,0.05,70,74,0.06" is how the 65-69 and 70-74 tiers would be stored). Relatively easy to parse then use. Then I realised that to implement this I would have to create a new table, a repository to wrap around it, data layer tests for the repo, unit tests around the code that unflattens the CSV into the table, and tests around the lookup itself. The only benefit of all this work is avoiding hard-coding the lookup table. When talking to the users (who currently use the lookup table directly - by looking at a hard copy) the opinion is pretty much that "the rates never change." Obviously that isn't actually correct - the rates were only created three years ago and in the past things that "never change" have had a habit of changing - so for me to defensively program this I definitely shouldn't store the lookup table in the application. Except when I think YAGNI. The feature I am implementing doesn't specify that the rates will change. If the rates do change, they will still change so rarely that maintenance isn't even a consideration, and the feature isn't actually critical enough that anything would be affected if there was a delay between the rate change and the updated application. I've pretty much decided that nothing of value will be lost if I hard-code the lookup, and I'm not too concerned about my approach to this particular feature. My question is, as a professional have I properly justified that decision? Hard-coding values is bad design, but going to the trouble of removing the values from the application seems to violate the YAGNI principle. EDIT To clarify the question, I'm not concerned about the actual implementation. I'm concerned that I can either do a quick, bad thing, and justify it by saying YAGNI, or I can take a more defensive, high-effort approach, that even in the best case ultimately has low benefits. As a professional programmer does my decision to implement a design that I know is flawed simply come down to a cost/benefit analysis?

    Read the article

  • How important is Programming for a Level Designer?

    - by WryGrin
    I'm currently attending school in a Level Design program, and I was wondering how important programming really is in being a Level Designer? I'm apparently incapable of learning programming (despite my best efforts), and tend to do very well in all other courses 3D modelling, story/character design, narrative and dialogue writing, environmental and conceptual design etc. I'm wondering if my strengths in the other areas are enough (with practice) to let me become a Level Designer, or I'm wasting my time if I can't program? I really want to be a Designer, but I just can't seem to wrap my head around the "language" of programming in general (Java kicks my teeth in even with tutoring and additional work on my own).

    Read the article

  • Design pattern for an ASP.NET project using Entity Framework

    - by MPelletier
    I'm building a website in ASP.NET (Web Forms) on top of an engine with business rules (which basically resides in a separate DLL), connected to a database mapped with Entity Framework (in a 3rd, separate project). I designed the Engine first, which has an Entity Framework context, and then went on to work on the website, which presents various reports. I believe I made a terrible design mistake in that the website has its own context (which sounded normal at first). I present this mockup of the engine and a report page's code behind: Engine (in separate DLL): public Engine { DatabaseEntities _engineContext; public Engine() { // Connection string and procedure managed in DB layer _engineContext = DatabaseEntities.Connect(); } public ChangeSomeEntity(SomeEntity someEntity, int newValue) { //Suppose there's some validation too, non trivial stuff SomeEntity.Value = newValue; _engineContext.SaveChanges(); } } And report: public partial class MyReport : Page { Engine _engine; DatabaseEntities _webpageContext; public MyReport() { _engine = new Engine(); _databaseContext = DatabaseEntities.Connect(); } public void ChangeSomeEntityButton_Clicked(object sender, EventArgs e) { SomeEntity someEntity; //Wrong way: //Get the entity from the webpage context someEntity = _webpageContext.SomeEntities.Single(s => s.Id == SomeEntityId); //Send the entity from _webpageContext to the engine _engine.ChangeSomeEntity(someEntity, SomeEntityNewValue); // <- oops, conflict of context //Right(?) way: //Get the entity from the engine context someEntity = _engine.GetSomeEntity(SomeEntityId); //undefined above //Send the entity from the engine's context to the engine _engine.ChangeSomeEntity(someEntity, SomeEntityNewValue); // <- oops, conflict of context } } Because the webpage has its own context, giving the Engine an entity from a different context will cause an error. I happen to know not to do that, to only give the Engine entities from its own context. But this is a very error-prone design. I see the error of my ways now. I just don't know the right path. I'm considering: Creating the connection in the Engine and passing it off to the webpage. Always instantiate an Engine, make its context accessible from a property, sharing it. Possible problems: other conflicts? Slow? Concurrency issues if I want to expand to AJAX? Creating the connection from the webpage and passing it off to the Engine (I believe that's dependency injection?) Only talking through ID's. Creates redundancy, not always practical, sounds archaic. But at the same time, I already recuperate stuff from the page as ID's that I need to fetch anyways. What would be best compromise here for safety, ease-of-use and understanding, stability, and speed?

    Read the article

  • Object Oriented Database - why most of the companies do not use them

    - by GigaPr
    Hi, I am pretty new to programming(just finished University). I have been thought in the last 4 years about Object Oriented development and the numerous advantages of this approach. My question is Isn't it easier to use a pure Object Oriented database in development applications? Why Object Oriented database are not as much diffuse as relational? From my point of view makes sense to use OO database, the latter will avoid the numerous construction necessary for the mapping of complex objects on the tables.

    Read the article

  • Facebook Game database design

    - by facebook-100000781341887
    Hi, I'm currently develop a facebook mafia like PHP game(of course, a light weight version), here is a simplify database(MySQL) of the game id-a <int3> <for index> uid <chr15> <facebook uid> HP <int3> <health point> exp <int3> <experience> money <int3> <money> list_inventory <chr5> <the inventory user hold...some special here, talk next> ... and 20 other fields just like reputation, num of combat... *the number next to the type is the size(byte) of the type For the list_inventory, there have 40 inventorys in my game, (actually, I have 5 these kind of list in my database), and each user can only contain 1 qty of each inventory, therefore, I assign 5 char for this field and each bit of char as 1 item(5 char * 8 bit = 40 slot), and I will do some manipulation by PHP to extract the data from this 5 byte. OK, I was thinking on this, if this game contains 100,000 user, and only 10% are active, therefore, if use my method, for the space use, 5 byte * 100,000 = 500 KB if I use another method, create a table user_hold_inventory, if the user have the inventory, then insert a record into this table, so, for 10,000 active user, I assume they got all item, but for other, I assume they got no item, here is the fields of the new table id-b <int3> <for index> id-a <int3> <id of the user table> inv_no <int1> <inventory that user hold> for the space use, ([id] (3+3) byte + [inv_no] 1 byte ) * [active user] 10,000 * [all inventory] * 40 = 2.8 MB seems method 2 have use more space, but it consume less CPU power. Please comment these 2 method or please correct me if there have another better method rather than what I think. Another question is, my database contain 26 fields, but I counted 5 of them are not change frquently, should I need to separate it on the other table or not? So many words, thanks for reading :)

    Read the article

  • Design Patterns for Coordinating Change Event Listeners

    - by mkraken
    I've been working with the Observer pattern in JavaScript using various popular libraries for a number of years (YUI & jQuery). It's often that I need to observe a set of property value changes (e.g. respond only when 2 or more specific values change). Is there a elegant way to 'subscribe' the handler so that it is only called one time? Is there something I'm missing or doing wrong in my design?

    Read the article

  • Design Patterns: What is a type

    - by contactmatt
    A very basic question, but after reading the "Design Patterns: Elements of reusable OO Software" book, I'm a little confused. The book states, "An object's type only refers to its interface-the set of request to which it can respond. An object can have many types, and objects of different classes can have the same type." Could someone please better explain what a Type is? I also don't understand how one object can have multiple types...unless the book is speaking of polymorphism....

    Read the article

  • PASS Summit 2010 Presentation Feedback

    - by andyleonard
    Introduction It's always an honor to present anywhere. Presenting at the PASS Summit is a special honor. I delivered three presentations last month: Database Design for Developers SSIS Design Patterns, Part 2 A Lightning Talk on SSIS Database Design for Developers First, a bit of explanation (defense): I submitted this abstract to the PASS Abstracts folks by mistake . I kid you not. Inspired by Adam Machanic ( Blog | @AdamMachanic ) I maintain a document of current presentations. I've recently published...(read more)

    Read the article

  • Class design for calling "the same method" on different classes from one place

    - by betatester07
    Let me introduce my situation: I have Java EE application and in one package, I want to have classes which will act primarily as cache for some data from database, for example: class that will hold all articles for our website class that will hold all categories etc. Every class should have some update() method, which will update data for that class from database and also some other methods for data manipulation specific for that data type. Now, I would like to call update() method for all class instances (there will be exactly one class instance for every class) from one place. What is the best design?

    Read the article

  • Help me to find a better approach-Design Pattern

    - by DJay
    I am working on an ASP.Net web application in which several WCF services are being used. At client level, I am creating channel factory mechanism to invoke service operations. Right now, I have created an assembly having classes used for channel factory creation code for every service. As per my assumption this is some sort of facade pattern. Please help me to find a better approach or any design pattern, which I can use here.

    Read the article

  • Object Oriented Design of a Small Java Game

    - by user2733436
    This is the problem i am dealing with. I have to make a simple game of NIM. I am learning java using a book so far i have only coded programs that deal with 2 classes. This program would have about 4 classes i guess including the main class. My problem is i am having a difficult time designing classes how they will interact with each other. I really want to think and use a object oriented approach. So the first thing i did was design the Pile CLASS as it seemed the easiest and made the most sense to me in terms of what methods go in it. Here is what i have got down for the Pile Class so far. package Nim; import java.util.Random; public class Pile { private int initialSize; public Pile(){ } Random rand = new Random(); public void setPile(){ initialSize = (rand.nextInt(100-10)+10); } public void reducePile(int x){ initialSize = initialSize - x; } public int getPile(){ return initialSize; } public boolean hasStick(){ if(initialSize>0){ return true; } else { return false; } } } Now i need help in designing the Player Class. By that i mean i am not asking for anyone to write code for me as that defeats the purpose of learning i was just wondering how would i design the player class and what would go on it. My guess is that the player class would contain method for choosing move for computer and also receiving the move human user makes. Lastly i am guessing in the Game class i am guessing the turns would be handeled. I am really lost right now so i was wondering if someone can help me think through this problem it would be great. Starting with the player class would be appreciated. I know there are some solutions for this problem online but i refuse to look at because i want to develop my own approach to such problems and i am confident if i can get through this problem i can solve other problems. I apologize if this question is a bit poor but in specific i need help in designing the Player class.

    Read the article

  • Choosing the right Design Pattern

    - by Carl Sagan
    I've always recognized the importance of utilizing design patterns. I'm curious as to how other developers go about choosing the most appropriate one. Do you use a series of characteristics (like a flowchart) to help you decide? For example: If objects are related, but we do not want to specify concrete class, consider Abstract When instantiation is left to derived classes, consider Factory Need to access elements of an aggregate object sequentially, try Iterator or something similar?

    Read the article

< Previous Page | 14 15 16 17 18 19 20 21 22 23 24 25  | Next Page >