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  • Good tool to visualise database schema?

    - by Mat
    Are there any good tools for visualising a pre-existing database schema? I'm using MySQL if it matters. I'm currently using MySQL Workbench to process an SQL create script dump, but it's clunky, slow and a manual process to drag all the tables about (which would be okay if it wasn't so slow).

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  • internal implementation of database Queries

    - by harigm
    In my experience I have used many queries like select, order by, where clause etc.. in mysql, sql-server, oracle etc For a moment i have thought, 1)how is this internally written to implement the above queries 2) which language do they use? 3) is that programming language? if yes which language? 4)what kind of environment required to implement this kind of complex database

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  • Adatbázis szerver konszolidáció Oracle technológiákkal - eroforrás allokálás

    - by Lajos Sárecz
    Szerver konszolidációnál alapmegoldás a virtualizáció, pedig az Oracle Database rendelkezik olyan képességekkel, melyekkel a virtualizáció elonyeit élvezhetjük, ám teljesítményben felülmúljuk azt. Több adatbázis konszolidációját meg lehet oldani egy nagy szerveren, vagy egy több szerverbol álló klaszteren. Bármelyik megoldást is választjuk (ezek elonyeivel és hátrányaival most nem foglalkozok), az egyik legfontosabb megoldandó probléma, hogy biztonsággal el tudjuk oket szeparálni akár adatbiztonsági, akár eroforrás kezelési szempontból. A szoftveres és hardveres virtualizációk lehetové teszik, hogy a szerver eroforrásait több virtuális szerver között felosszuk, ezáltal elszeparálhatók a párhuzamosan futó adatbázis példányok. Ezek a megoldások általában költségesek, plusz adminisztrációt jelentenek és teljesítmény csökkenést okoznak. Az alábbiakban röviden összeszedem, hogy az Oracle Database milyen eroforrás szeparációs technológiákkal rendelkezik, melyek jól használhatók adatbázis konszolidáció esetén: Adatbázis szolgáltatások: Azt talán minden Oracle adatbázis-kezelovel foglalkozó szakérto tudja, hogy akliensek az adatbázist az adatbázis szolgáltatás nevével érik el. Alapértelmezetten minden adatbázis egyetlen szolgáltatással rendelkezik, mely automatikusan a 'global database name' paraméterrel megegyezo nevet kapja az adatbázis létrehozásakor. Ugyanakkor egy adatbázishoz több szolgáltatás név is rendelheto. A szolgáltatásokkal csoportosíthatók a különbözo feladatokat végrehajtó kliensek, és a szolgáltatásokhoz rendelhetjük hogy melyik kliens csoportnak mennyi rendszer eroforrást allokálunk. Klaszteres adatbázisok (RAC) esetén egy szolgáltatás több adatbázis példányhoz (szerverhez) kapcsolódhat, amivel valós terheléstol függo terhelés elosztás valósítható meg (itt már szerepet kap egyébként a Resource Manager is, lásd késobb). Az alkalmazás számára irrelevánssá válik, hogy az adott szolgáltatást mely szerver szolgálja ki. A szolgáltatásokhoz kapcsolódó eroforrások menet közben dinamikusan bovíthetok, de kezelik a kieso eroforrások hiányát is (failover). Database Resource Manager: Az Oracle Database Resource Manager az adatbázis szintjén kezeli az eroforrásokat, a CPU használatot szabályozza az adatbázis terhelés kontrolljával. A Resource Manager egy CPU-n adott pillanatban csak egyetlen Oracle processz futtatását engedélyezi, miközben a többit várakoztatja (ahogy az egy operációs rendszer ütemezojében is muködik). A Resource Manager csak akkor lép muködésbe, amikor a CPU terhelése eléri a 100%-ot. Ekkor a Resource Plan-nek megfeleloen korlátozhatja az egyes eroforrás csoportok számára elérheto eroforrás (CPU) mennyiségét. Instance Caging: A Resource Manager részeként az Oracle Database 11gR2-tol elérheto Instance Caging technológiával virtualizáció és operációs rendszer szintu eroforrás felosztás nélkül az adatbázis példány szintjén lehet szabályozni az allokált CPU számot. Erre akkor lehet szükség, ha egy szerveren több példány futtatására van szükség. A Resource Manager bekapcsolásával és a cpu_count paraméter beállításával lehet adatbázis példányonként aktiválni az Instance Caging funkcionalitást. A cpu_count egy dinamikus paraméter, célszeru arra az értékre állítani, ahány CPU-t az adott adatbázis példány maximálisan igényelhet. Lehetoség van túlméretezni a példányok számára rendelkezésre álló processzorok számát. Például egy 4 CPUs- szerver esetében ha van 3 példányunk, mindháromnak adhatunk 3 CPU-t. Azonban ha mindegyik terhelés alatt van, akkor a példány számára maximum allokált CPU szám osztva összes allokált CPU számmal arányban részesül a processzorból, ami a példában 33,33%, azaz 1,33 CPU. Input Output Resource Manager (IORM):Nem csak a processzorok használatát szabályozhatjuk, lehetoség van a megosztott storage eroforrásainak felosztására is. Az Input Output Resorce Manager (IORM) alkalmazásával storage szinten tudjuk szabályozni az adatbázisok közötti és azokon belüli minimális I/O szinteket. Database Vault: Ugyanazon adatbázisba konszolidált alkalmazások esetén a rendszergazda szerepkörök szeparálása lehetséges az Oracle Database Vault technológiával. Ezzel elérheto az, hogy biztonságosan konszolidáljuk adatbázisainkat úgy, hogy minden adminisztrátor csak a hozzá tartozó adatokat, objektumokat lássa, módosíthassa.

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  • From a DDD perspective is a report generating service a domain service or an infrastructure service?

    - by Songo
    Let assume we have the following service whose responsibility is to generate Excel reports: class ExcelReportService{ public String generateReport(String fileFormatFilePath, ResultSet data){ ReportFormat reportFormat = new ReportFormat(fileFormatFilePath); ExcelDataFormatterService excelDataFormatterService = new ExcelDataFormatterService(); FormattedData formattedData = excelDataFormatterService.format(data); ExcelFileService excelFileService = new ExcelFileService(); String reportPath= excelFileService.generateReport(reportFormat,formattedData); return reportPath; } } This is pseudo code for the service I want to design where: fileFormatFilePath: path to a configuration file where I'll keep the format of my excel file (headers, column widths, number of columns,..etc) data: the actual records returned from the database. This data can't be used directly coz I might need to make further calculations to the data before inserting them to the excel file. ReportFormat: Value object to hold the report format, has methods like getHeaders(), getColumnWidth(),...etc. ExcelDataFormatterService: a service to hold any logic that need to be applied to the data returned from the database before inserting it to the file. FormattedData: Value object the represents the formatted data to be inserted. ExcelFileService: a wrapper top the 3rd party library that generates the excel file. Now how do you determine whether a service is an infrastructure or domain service? I have the following 3 services here: ExcelReportService, ExcelDataFormatterService and ExcelFileService?

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  • Defining formula through user interface in user form

    - by BriskLabs Pakistan
    I am a student and developing a simple assignment - windows form application in visual studio 2010. The application is suppose to construct formulas as per user requirement. The process: It has to pick data from columns of Microsoft Access database and the user should be able to pick the data by column name like we do in a drop down menu. and create reusable formulas in it ( configure it once and can change it again). followings are column titles from database that can be picked for example. e.g Col -1 : Marks in Maths Col -2 : Total Marks in Maths Col -3 : Marks in science Col -4 : Total marks in science Finally we should be able to construct any formula in the UI like (Col 1 + Col 3 ) / ( col 2 + col 4) = Formula 1 once this is formula is set saved and a name is assigned to it by user. he/she can use the formula and results shall appear in a window below. i.e He would be able to calculate his desired figures (formula) by only manipulating underlying data on the UI layer....choose the data for a period and apply the formula and get the answer Problem: It looks like I have to create an app where rules are set through UI....... this means no stored procedures are required in SQL.... please suggest the right approach.

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  • Should pathfinder in A* hold closedSet and openedSet or each object should hold its sets?

    - by Patryk
    I am about to implement A* pathfinding algorithm and I wonder how should I implement this - from the point of view of architecture. I have the pathfinder as a class - I think I will instantiate only one object of this class (or maybe make it a Singleton - this is not so important). The hardest part for me is whether the closedSet and openedSet should be attached to objects that can find the path for them or should be stored in pathfinder class ? I am opened to any hints and critique whatsoever. What is the best practice considering pathfinding in terms of design ?

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  • What is a best practice tier structure of a Java EE 6/7 application?

    - by James Drinkard
    I was attempting to find a best practice for modeling the tiers in a Java EE application yesterday and couldn't come up with anything current. In the past, say java 1.4, it was four tiers: Presentation Tier Web Tier Business Logic Tier DAL (Data Access Layer ) which I always considered a tier and not a layer. After working with Web Services and SOA I thought to add in a services tier, but that may fall under 3. the business logic tier. I did searches for quite a while and reading articles. It seems like Domain Driven Design is becoming more popular, but I couldn't find a diagram on it's tier structure. Anyone have ideas or diagrams on what the proper tier structure is for newer Java EE applications or is it really the same, but more items are ranked under the four I've mentioned?

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  • How to update a game off a database

    - by James Clifton
    I am currently writing a sports strategy management game (cricket) in PHP, with a MYSQL database, and I have come across one stumbling block - how do I update games where neither player is online? Cricket is a game played between two players, and when they (or one of them) is online then everything is fine; but what if neither player is online? This occurs when championship games are played, and these games need to happen at certain times for game reasons. At the moment I have a private web page that updates every 5 seconds, and each time it loads all games are updated; but then I have the problem that when my private web page stops (for example my computer crashes or my web browser plays up) the game stops updating! Any suggestions?

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  • Customizing configuration with Dependency Injection

    - by mathieu
    I'm designing a small application infrastructure library, aiming to simplify development of ASP.NET MVC based applications. Main goal is to enforce convention over configuration. Hovewer, I still want to make some parts "configurable" by developpers. I'm leaning towards the following design: public interface IConfiguration { SomeType SomeValue; } // this one won't get registered in container protected class DefaultConfiguration : IConfiguration { public SomeType SomeValue { get { return SomeType.Default; } } } // declared inside 3rd party library, will get registered in container protected class CustomConfiguration : IConfiguration { public SomeType SomeValue { get { return SomeType.Custom; } } } And the "service" class : public class Service { private IConfiguration conf = new DefaultConfiguration(); // optional dependency, if found, will be set to CustomConfiguration by DI container public IConfiguration Conf { get { return conf; } set { conf = value; } } public void Configure() { DoSomethingWith( Conf ); } } There, the "configuration" part is clearly a dependency of the service class, but it this an "overuse" of DI ?

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  • How does a search functionality fit in DDD with CQRS?

    - by Songo
    In Vaughn Vernon's book Implementing domain driven design and the accompanying sample application I found that he implemented a CQRS approach to the iddd_collaboration bounded context. He presents the following classes in the application service layer: CalendarApplicationService.java CalendarEntryApplicationService.java CalendarEntryQueryService.java CalendarQueryService.java I'm interested to know if an application will have a search page that feature numerous drop downs and check boxes with a smart text box to match different search patterns; How will you structure all that search logic? In a command service or a query service? Taking a look at the CalendarQueryService.java I can see that it has 2 methods for a huge query, but no logic at all to mix and match any search filters for example. I've heard that the application layer shouldn't have any business logic, so where will I construct my dynamic query? or maybe just clutter everything in the Query service?

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  • Why is nesting or piggybacking errors within errors bad in general?

    - by dietbuddha
    Why is nesting or piggybacking errors within errors bad in general? To me it seems bad intuitively, but I'm suspicious in that I cannot adequately articulate why it is bad. This may be because it is not in general bad and that it is only bad in specific instances. Why is it detrimental to design error/exception handling in such a way. The specific instance is that of a REST service. There is a desire by some to use http errors (specifically the 500 response) as a way to indicate any problem with specific instances of a resource. An example of an instance resource in this case would be: http://server/ticket/80 # instance http://server/ticket # not an instance So this is the behavior that is being proposed. If ticket 80 does not exist return a http response code of 500. Within the body of the error return the "real" error as an additional error code and description. If the ticket resource doesn't exist return a response code of 404.

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  • What is the difference between all-static-methods and applying a singleton pattern?

    - by shahensha
    I am making a database to store information about the users of my website (I am using stuts2 and hence Java EE technology). For the database I'll be making a DBManager. Should I apply singleton pattern here or rather make all it's methods static? I will be using this DBManager for basic things like adding, deleting and updating User profiles. Along with it, I'll use for all other querying purposes, for instance to find out whether a username already exists and to get all users for administrative purposes and stuff like that. My questions What is the benefit of singleton pattern? Which thing is most apt here? All static methods or a singleton pattern? Please compare both of them. regards shahensha P.S. The database is bigger than this. Here I am talking only about the tables which I'll be using for storing User Information.

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  • Is it a good idea to simplify an character -driven game engine to the point it's unnecessary to learn scripting/programming ?

    - by jokoon
    I remember, and I still think, that one cannot even make a prototyped 3D game to test just simple behaviors without using gigantic tools like unity or knowing extensive C++ programming, design pattern, a decent or basic 3D engine, etc. Now I'm wondering, since I know programming, that I'm still more lucky that the ones who need to learn programming prior to know how to make something: even scripted engines such as unity are not for kids, and to my sense they tend to dictate their ways of doing things, which is not the case with engine like ogre or irrlicht. I remember toying a little with the blender game engine, it was possible to link states or something I don't remember very well. Now I'm thinking that character driven games occupies a big part of the game market. Do you think it is a good idea to make a character-controlled oriented game engine which allows only to build AI instead of anything else ?

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  • Is it bad practice to pass instances through several layers?

    - by Puckl
    In my program design, I often come to the point where I have to pass object instances through several classes. For example, if I have a controller that loads an audio file, and then passes it to a player, and the player passes it to the playerRunnable, which passes it again somewhere else etc. It looks kind of bad, but I don´t know how to avoid it. Or is it OK to do this? EDIT: Maybe the player example is not the best because I could load the file later, but in other cases that does not work.

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  • Earliest use of Comments as Semantically Meaningful Things in a Program?

    - by Alan Storm
    In certain corners of the PHP meta-programming world, it's become fashionable to use PHPDoc comments as a mechanism for providing semantically meaningful information to a program. That is, other code will parse the doc blocks and do something significant with the information encoded in those comments. Doctrine's annotations and code generation are an example of this. What's the earliest (or some early) use of this technique? I have vague memories of some early java Design by Contract implementations doing similar things, but I'm not sure of those folks were inventing the technique, or if they got it from somewhere. Mainly asking so I can provide some historical context for PHP developers who haven't come across the technique before, and are distrustful of it because it seems a little crazy pants.

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  • Subscribe/Publish Model in Web-based Application (c#) - Best Practices for Event Handlers

    - by KingOfHypocrites
    I was recently exposed to a desktop application that uses an publish/subscribe model to handle commands, events, etc. I can't seem to find any good examples of using this in a web application, so I wonder if I am off base in trying to use this for web based development (on the server side)? I'm using asp.net c#. My main question in regards to the design is: When using a publish/subscribe model, is it better to have generic commands/events that pass no parameters and then have the subscribers look at static context objects that contain the data relevant to the event? Or is it better to create custom arguments for every event that contain data related to the event? The whole concept of a global container seems so convenient but at the same time seems to break encapsulation. Any thoughts or best practices from anyone who has implemented this type of model in a web based application? Even suggestions on this model out of the scope of my question are appreciated.

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  • How to change the state of a singleton in runtime

    - by user34401
    Consider I am going to write a simple file based logger AppLogger to be used in my apps, ideally it should be a singleton so I can call it via public class AppLogger { public static String file = ".."; public void logToFile() { // Write to file } public static log(String s) { AppLogger.getInstance().logToFile(s); } } And to use it AppLogger::log("This is a log statement"); The problem is, what is the best time I should provide the value of file since it is a just a singleton? Or how to refactor the above code (or skip using singleton) so I can customize the log file path? (Assume I don't need to write to multiple at the same time) p.s. I know I can use library e.g. log4j, but consider it is just a design question, how to refactor the code above?

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  • Event Aggregator.. not getting a response, how to determine completion?

    - by Duncan_m
    I'm rewriting a vehicle tracking application, a google maps based thing.. The users are able to search for a vehicle by typing a few characters of the vehicles "callsign". My application is based around a sort of "event bus" within Backbone.. when a search occurs I send a message on the bus saying something like "does anyone match this?".. If a marker matches the search term it responds with a sort of "yes, I match!".. My challenge arises when no-one matches, I get no response.. it feels a little hacky to "wait a little while" and check if a response has been recieved.. The application is based around Backbone.js and using the Event Aggregator pattern described in the answer to this question on Stack Overflow: http://stackoverflow.com/questions/7708195/access-function-in-one-view-from-another-in-backbone-js Is there a well defined design pattern that might assist me here? Sending a request for a response and not getting any responses?

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  • When designing an application around Model-View-Controller (MVC), what is in your toolbox?

    - by ericgorr
    There are a lot of great explanations for what the Model-View-Controller design pattern is, but I am having trouble finding good resources showing how to use it in practice. So, when you are starting a new application (doesn't matter what it is), what is in your toolbox? For example, it was suggested that using UML collaboration diagrams ( http://www.objectmentor.com/resources/articles/umlCollaborationDiagrams.pdf ) can be useful when designing an application around MVC, although, I am not certain exactly how or why this might be the case...? So, what is in your toolbox for MVC?

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  • Best Way to Handle Meta Information in a SQL Database

    - by danielhanly.com
    I've got a database where I want to store user information and user_meta information. The reason behind setting it up in this way was because the user_meta side may change over time and I would like to do this without disrupting the master user table. If possible, I would like some advice on how to best set up this meta data table. I can either set it as below: +----+---------+----------+--------------------+ | id | user_id | key | value | +----+---------+----------+--------------------+ | 1 | 1 | email | [email protected] | | 2 | 1 | name | user name | | 3 | 1 | address | test address | ... Or, I can set it as below: +----+---------+--------------------+--------------------+--------------+ | id | user_id | email | name | address | +----+---------+--------------------+--------------------+--------------+ | 1 | 1 | [email protected] | user name | test address | Obviously, the top verison is more flexible, but the bottom version is space saving and perhaps more efficient, returning all the data as a single record. Which is the best way to go about this? Or, am I going about this completely wrong and there's another way I've not thought of?

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  • Distinguishing between sets of status reports

    - by user1769486
    I am working on an internal database monitoring system and am at a point where I sort of hit the wall in terms of application design. Basically I have an extensible plugin architecture where I shall have an OK, a warning or an error upon running a db verification. My first question whether it is sufficient to have only one status reported with an optional status message or provide the ability to have more than one returned (with attached messages) and then calculate an aggregated overall status. In particular in the latter case my second issue would be how to distinguish between two verification reports with the same status code (as it can come from different triggers). I would need to do this to see whether some change happened between the current and last verification. I could simply have string comparisons of the attached status messages mentioned above but that does not seem very reliable.

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  • ?????????????????!Oracle Database ?????????

    - by Aya Sensui
    ?????????????????????????????????? ?????????????????????????????????????????????? ?????????????????????????????????????????????????? ??????????????????????????????????????????? ?????????????????????????????????? ??????????????????????????????????????????????? ?????????/?????????????????????????????????????????? ?????????????? ????????????????????????????????????????? ???????????????????????????????????? ??????????????????????????????????????????????? ????????????????????????????????????????????????????????? Oracle Database ????????????????? ??????????????????????????? ????????????????????????? ???????????????????????? ????????????????????????????????? ???????????????? ??????????????????????????????????!??????? ??????????????????? TIPS ???????????????? ?????!???????? ???????????????????????????????????????????????? Oracle Database ??????????????????????????????????????????? ??????????????????????????????????????? Oracle Database ????????????????????????????????????? ????????? FAILED_LOGIN_ATTEMPTS    ??????????? PASSWORD_LIFE_TIME       ????????? PASSWORD_REUSE_TIME      ???????????????????? PASSWORD_REUSE_MAX       ????????????????????????????? PASSWORD_LOCK_TIME       ????????????????????????????????????? PASSWORD_GRACE_TIME      ????????????????? PASSWORD_VERIFY_FUNCTION ??????????????????? (*1) (*1)????????????????????????? $ORACLE_HOME/rdbms/admin/utlpwdmg.sql ?????????????????? utlpwdmg.sql ????????? ???????????????????????????  - ?????????????????  - ???????????  - ??????????????  - ?????????????????????  - ???????????????????? ???????????????????????????????????? ???????????????????????????????????? ??????????????????????!?????? ????????????????????????????????????? ??????????????????????????????????? ????????????????????? ???????? SQL*Plus ??????????????????????? ????????????????????????? ???????????????????????????????????? ??????????????????·???????????????? ???Enterprise Edition ?????????????????? Virtual Private Database(VPD) ??????????? ???????????????????????????????????????????????? ?????????????????????????? ???????????????????????????????????????????????? ????????????????????????????? ?????????????????????????????????? ????????????????????????????? ??????????????????????????????????? ???????????????????? ?????????????????????????????? ???????????????????????????????? ????????????????????????????????????????? ??????????????????????????????????????????? ????????????????????????????? Oracle Database ????????????????????Oracle Advanced Security ????????????? ?????????????????????????????? ????DBMS_OBFUSCATION_TOOLKIT ? DBMS_CRYPTO ???????/????? PL/SQL ?????? ?????????????????? ?????????????????????????????????????????????? ?????????????????????????? ????????????!???? Oracle Database ?????????????????????????????????? ????????????????????????DBA ??????????????????? 4 ???? ??????????? Enterprise Edition??????????? ?????DBA ??????????????????????? ?????????????????????? [????] ???????????????????????????????????? ????????????????????  - ????????????  - ?????(SYSOPER, SYSDBA)???????????  - ??????????(??????????) ?????????????????????????????????·?????? ????????????????????????????????? ?????????????????????????????? [DBA ??] ???????????(DBA ??)???????????????????? ??????????????????????????AUDIT_SYS_OPERATIONS ?????? TRUE ????????????? ????? OS ??????????????/????????????????????? ???????????????????????????????????????????????? [????] ???????????????????????????????????? ??AUDIT_TRAIL ??????????????????????????? ???????????  - ???????    ????·????????  - ????????    ??????????????????????????????  - ????    ????????????????  - SQL ???    ????????????? DDL ?????? [??????????] ??????(?????????)??????????????????? Enterprise Edition ?????????? ??????????????????????? ??? Oracle Database ???????????????????????????????????? ??????????????????????????????????????????????? ????????????????????

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  • jBASE 4.1 Database Noobster Questions

    - by Steve Johnson
    I am a software developer with devlopment experience in C#, C++ .Net alongwith SQL Server 2005/08, Oracle and mysql. But somehow i dont get jBASE to work at Windows XP SP3 machine. My goal is setup user accounts, create database on a JBASE ainstallation, authenticate and backup/restore few table via a C++ program. And i dont need to do it with builtin backup/restore tools of jBASE. I am able to install jBASe 4.1 aling with all its accessories on my WINXPSP3 machine. I was able to run the jSlimserver and TEMENOUS server along with licnesing server. I was able to add the license key as well. But after that what i was supposed to do? i have no idea about it. The docs and online help doesnt answer a simple question of how to create a database! The google search results from the jbase site all go to the 404 Pages! Can a jBASE expert guide to the following steps: Create a jBASE database. Create users Authenticate via those users Connect to database Create tables and insert data. Connect via a C++ or C# program to connect to jBASE DB and backup/restore tables. I know that this is too much too ask but i dont get to get the JBASE system. I cant get it to work on my System somehow. Btw, jdc and jexloree doesnt seem to do anything. I have checked that enironmental variables for jBASE are setup correctly and i have verified them. There are no extra JRE or JDK installations on my system. Besides all that, only licensing client, slim server and temenous server seem to run and listen for connections and no other execuatable ever seems to work. A simple tutorial to achieve the objective will be highly appreciated. Also if anyone can point out the mistake that i have done or anything i might need to check, then please do so. I will be highly encouraged and obliged. Thanks Steve

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