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  • Best practice - logging events (general) and changes (database)

    - by b0x0rz
    need help with logging all activities on a site as well as database changes. requirements: * should be in database * should be easily searchable by initiator (user name / session id), event (activity type) and event parameters i can think of a database design but either it involves a lot of tables (one per event) so i can log each of the parameters of an event in a separate field OR it involves one table with generic fields (7 int numeric and 7 text types) and log everything in one table with event type field determining what parameter got written where (and hoping that i don't need more than 7 fields of a certain type, or 8 or 9 or whatever number i choose)... example of entries (the usual things): [username] login failed @datetime [username] login successful @datetime [username] changed password @datetime, estimated security of password [low/ok/high/perfect] @datetime [username] clicked result [result number] [result id] after searching for [search string] and got [number of results] @datetime [username] clicked result [result number] [result id] after searching for [search string] and got [number of results] @datetime [username] changed profile name from [old name] to [new name] @datetime [username] verified name with [credit card type] credit card @datetime datbase table [table name] purged of old entries @datetime via automated process etc... so anyone dealt with this before? any best practices / links you can share? i've seen it done with the generic solution mentioned above, but somehow that goes against what i learned from database design, but as you can see the sheer number of events that need to be trackable (each user will be able to see this info) is giving me headaches, BUT i do LOVE the one event per table solution more than the generic one. any thoughts? edit: also, is there maybe an authoritative list of such (likely) events somewhere? thnx stack overflow says: the question you're asking appears subjective and is likely to be closed. my answer: probably is subjective, but it is directly related to my issue i have with designing a database / writing my code, so i'd welcome any help. also i tried narrowing down the ideas to 2 so hopefully one of these will prevail, unless there already is an established solution for these kinds of things.

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  • Entity framework and database logic.

    - by Xavier Devian
    Hi all, i have a question that's being around for several years. As all you know entity framework is an ORM tool that tries to model the database to an object oriented access model. All the samples I've seen are quering directly to the database tables. So, which is the role of the views in the database now?. The views were used to model the database in a more friendly way, that is, several physical tables, one logic table. This was great for example in hidding the complex relational model on stored procedures as queryng the views inside them was much easier than reproducing the query joins over and over on each stored procedure. So the question is, why is entity framework so good if stored procedures can not take benefit of it?

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  • Automatic database generation / migration with perl

    - by pistacchio
    Hi, In Ror or Django or web2py you can "describe" a database (as a set of classes that remaps to tables) and the framework (having being provided with a connection string to the desired database) generates the tables, fields, relations and in the case of RoR and web2py it also keeps it up-to-date (eg, removing a class drops the table, adding a property to the class triggers an "alter table add" etc). Is there any perl module that does the same? Eg, it takes the YAML / XML / JSON description of a database as input and modifies / generates the database accordingly? Thanks in advance.

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  • Android database closed exception

    - by Bombastic
    I'm working on a project where I'm downloading and saving data from web to sqlite database. A few minutes ago I receive a strange exception to our server from a user which is saying that the sqlite database is already closed..and I just checked the whole file where the exception happened and I'm not calling dbHelper.close();. Here is the function where the app crashes and LogCat message : public void insertCollectionCountries(JSONObject obj, Context context) { //Insert in collection_countries if(RPCCommunicator.isServiceRunning){ Log.w("","JsonCollection - insertCollectionCountries"); ContentValues valuesCountries = new ContentValues(); try { collectionId = Integer.parseInt(obj.getString("collection_id")); dbHelper.deleteSQL("collection_countries", "collection_id=?", new String[] {Integer.toString(collectionId)}); JSONArray arrayCountries = obj.getJSONArray("country_availability"); for (int i=0; i<arrayCountries.length(); i++) { valuesCountries.put("collection_id", collectionId); String countryCode = arrayCountries.getString(i); valuesCountries.put("country_code", countryCode); dbHelper.executeQuery("collection_countries", valuesCountries); } } catch (JSONException e){ e.printStackTrace(); } } } and the error is on that line : dbHelper.executeQuery("collection_countries", valuesCountries); here is the LogCat message : java.lang.IllegalStateException: database /data/data/com.stampii.stampii/databases/stampii_sys_tpl.sqlite (conn# 0) already closed at android.database.sqlite.SQLiteDatabase.verifyDbIsOpen(SQLiteDatabase.java:2123) at android.database.sqlite.SQLiteDatabase.setTransactionSuccessful(SQLiteDatabase.java:734) at com.stampii.stampii.comm.rpc.SystemDatabaseHelper.execQuery(SystemDatabaseHelper.java:298) at com.stampii.stampii.comm.rpc.SystemDatabaseHelper.executeQuery(SystemDatabaseHelper.java:291) at com.stampii.stampii.jsonAPI.JsonCollection.insertCollectionCounries(JsonCollection.java:548) at com.stampii.stampii.jsonAPI.JsonCollection.executeInsert(JsonCollection.java:181) at com.stampii.stampii.collections.MyService.downloadCollections(MyService.java:122) at com.stampii.stampii.collections.MyService$2.run(MyService.java:74) at java.lang.Thread.run(Thread.java:1020) and function in my dbHelperClass which I'm using to insert data : public boolean executeQuery(String tableName,ContentValues values){ return execQuery(tableName,values); } private boolean execQuery(String tableName,ContentValues values){ sqliteDb = instance.getWritableDatabase(); sqliteDb.beginTransaction(); sqliteDb.insert(tableName, null, values); sqliteDb.setTransactionSuccessful(); sqliteDb.endTransaction(); return true; } Any ideas which can close my sqlite database or what can cause that exception, because I've tested this code on a few emulators with different Android versions, different devices (HTC EVO 3D, Samsung Galaxy Nexus,HTC Desire, LG OPTIMUS PAD, Samsung Galaxy S2, Samsung Galaxy Note) and it's working fine. Thanks in advance!

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  • Google App Engine Database Index

    - by fjsj
    I need to store a undirected graph in a Google App Engine database. For optimization purposes, I am thinking to use database indexes. Using Google App Engine, is there any way to define the columns of a database table to create its index? I will need some optimization, since my app uses this stored undirected graph on a content-based filtering for item recommendation. Also, the recommender algorithm updates the weights of some graph's edges. If it is not possible to use database indexes, please suggest another method to reduce query time for the graph table. I believe my algorithm does more data retrieval operations from graph table than write operations. PS: I am using Python.

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  • How do I create and link to a database in ASP.NET (Razor) with Visual studio 2013?

    - by Blake
    We have a simple web app, part of which allows users to create accounts and then, hopefully soon, to write blog posts. The user log in system is working great, it utilizes the given .sdf database created when a new project is created. We would like to expand it now to allow for blog data (the title, body of the blog, image posts perhaps, etc). However, I'm unsure of how to add another table to the user database for this purpose - or if that would even be best since it has sensitive information in it. I've been reading blog post after blog post and still can't find anything current on this. All of the articles are for MVC projects or older versions of VS. If someone could point me in the right direction it would be greatly appreciated!

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  • Oracle Unveils Breakthrough Technology: Database In-Memory

    - by Mala Narasimharajan
    Missed Larry Ellison's big announcement this morning? Today, Oracle announced . Oracle Database In-Memory.  Oracle Database In-Memory  transparently extends the power of Oracle Database 12c to enable organizations to discover business insights in real-time while simultaneously increasing transactional performance. Here's why you should care - this new breakthrough technology enables enterprises to get faster answers to business questions ultimately leading to faster business action. Oracle Database In-Memory delivers leading-edge in-memory performance without the need to restrict functionality or accept compromises, complexity and risk. Deploying Oracle Database In-Memory with virtually any existing Oracle Database-compatible application is as easy as flipping a switch--no application changes are required.  For more information on Oracle Database In-Memory go to http://www.oracle.com/us/corporate/press/2215795

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  • Can I create my own database from PHP?

    - by Roman
    I have a working PHP server. Now I want to use databases (MySQL or something similar). Is it possible to create a database from PHP? I would like to emphasize that in my case I do not have any user-name and password to which I can use to connect to MySQL server. I also do not have a control-panel where I could create a database or a table in an existing database.

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  • Should concrete classes avoid calling other concrete classes, except for data objects?

    - by Kazark
    In Appendix A to The Art of Unit Testing, Roy Osherove, speaking about ways to write testable code from the start, says, An abstract class shouldn't call concrete classes, and concerete classes shouldn't call concrete classes either, unless they're data objects (objects holding data, with no behavior). (259) The first half of the sentence is simply Dependency Inversion from SOLID. The second half seems rather extreme to me. That means that every time I'm going to write a class that isn't a simple data structure, which is most classes, I should write an interface or abstract class first, right? Is it really worthwhile to go that far in defining abstract classes an interfaces? Can anyone explain why in more detail, or refute it in spite of its benefit for testability?

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  • Bulletin board - Database optimisation

    - by andrew
    This question is a follow on from this Question The project and problem The project I am currently working on is a bulletin board for a large non-profit organisation. The bulletin board will be used to allow inter-office communication within the organisation. I am building the application and have been having trouble extracting the results that I need from my database because I don't think it is properly normalized and because of limitations in my knowledge of relational database theory and mysql. I would appreciate input into the design of the board in general and in particular, ways that the database structure can be improved to facilitate efficient queries and help me develop this application and future application faster Business Logic The bulletin board will be used in the following way Posting bulletins and responses to bulletins Employees or 'users' in offices around the country will be able to post messages to the bulletin board.Bulletins must be posted to a location and categorised- i'll call these "bulletins". Users will be able to post any number of replies to any one bulletin and users will be able to reply to their own bulletin - i'll call these 'replies'. Rating bulletins and replies Users will be able to either 'like' or 'dislike' a bulletin or a reply and the total number of likes or dislikes will be shown for each bulletin or reply. Viewing the bulletin board and responses Bulletins can be displayed chronologically. Users can sort bulletins chronologically or chronologically by the latest reply to that bulletin(let me know if you need more explanation) When a particular bulletin is selected, replies to that bulletin will be displayed chronologically @PerformanceDBA - edited 10:34 est 28/12/10I have begun implementing the data model. I assume that the 6th data model is the physical model because it contains the associative tables. I am going to post any questions that I have below. I will put up a database dump once I am done. I will then put up a list of all the queries that I need to run on the database and begin writing them. I hope you had a good Christmas. I'm in Canada and there's snow! Implementation of Physical model

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  • Start developing a database application using Oracle + Net Beans

    - by Ranhiru
    I have thought of creating my first database application for one of my projects using Oracle and Java. I have chosen Netbeans as my development environment. I have a few questions to getting started. Please bare with me as I'm a complete beginner to Oracle + Netbeans This will be a data intensive (yet still for a college project) database application. I do not need 1000 user concurrency or any other very advanced features but basic stuff such as triggers, stored procedures etc. Will the 11g "Express" (XE) suffice for my requirements? Do i need any Java to Oracle bridge (database connectivity driver eg. ODBC etc) for Netbeans to connect to the oracle database? If yes, what are they? Does Netbeans support Oracle databases natively? Any easy to follow guide on how do i connect to the database and insert/retrieve/display data on a J2SE application? (I know that i should Google this but if there's any guide previously followed by anyone and is considered easy, it would be greatly appreciated.)

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  • Understanding the levels of computing

    - by RParadox
    Sorry, for my confused question. I'm looking for some pointers. Up to now I have been working mostly with Java and Python on the application layer and I have only a vague understanding of operating systems and hardware. I want to understand much more about the lower levels of computing, but it gets really overwhelming somehow. At university I took a class about microprogramming, i.e. how processors get hard-wired to implement the ASM codes. Up to now I always thought I wouldn't get more done if learned more about the "low level". One question I have is: how is it even possible that hardware gets hidden almost completely from the developer? Is it accurate to say that the operating system is a software layer for the hardware? One small example: in programming I have never come across the need to understand what L2 or L3 Cache is. For the typical business application environment one almost never needs to understand assembler and the lower levels of computing, because nowadays there is a technology stack for almost anything. I guess the whole point of these lower levels is to provide an interface to higher levels. On the other hand I wonder how much influence the lower levels can have, for example this whole graphics computing thing. So, on the other hand, there is this theoretical computer science branch, which works on abstract computing models. However, I also rarely encountered situations, where I found it helpful thinking in the categories of complexity models, proof verification, etc. I sort of know, that there is a complexity class called NP, and that they are kind of impossible to solve for a big number of N. What I'm missing is a reference for a framework to think about these things. It seems to me, that there all kinds of different camps, who rarely interact. The last few weeks I have been reading about security issues. Here somehow, much of the different layers come together. Attacks and exploits almost always occur on the lower level, so in this case it is necessary to learn about the details of the OSI layers, the inner workings of an OS, etc.

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  • What database strategy to choose for a large web application

    - by Snoopy
    I have to rewrite a large database application, running on 32 servers. The hardware is up to date, each machine has two quad core Xeon and 32 GByte RAM. The database is multi-tenant, each customer has his own file, around 5 to 10 GByte each. I run around 50 databases on this hardware. The app is open to the web, so I have no control on the load. There are no really complex queries, so SQL is not required if there is a better solution. The databases get updated via FTP every day at midnight. The database is read-only. C# is my favourite language and I want to use ASP.NET MVC. I thought about the following options: Use two big SQL servers running SQL Server 2012 to serve the 32 servers with data. On the 32 servers running IIS hosting providing REST services. Denormalize the database and use Redis on each webserver. Use booksleeve as a Redis client. Use a combination of SQL Server and Redis Use SQL Server 2012 together with Hadoop Use Hadoop without SQL Server What is the best way for a read-only database, to get the best performance without loosing maintainability? Does Map-Reduce make sense at all in such a scenario? The reason for the rewrite is, the old app written in C++ with ISAM technology is too slow, the interfaces are old fashioned and not nice to use from an website, especially when using ajax. The app uses a relational datamodel with many tables, but it is possible to write one accerlerator table where all queries can be performed on, and all other information from the other tables are possible by a simple key lookup.

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  • Using a CMS with an external database

    - by George Reith
    I am looking at building an external site with a CMS, probably Drupal or ExpressionEngine. The problem is that our company already has a membership database that is designed to work with our existing enterprise software. Migrating data from the database manually is not an option as modifications and new data must be accessible in real-time. Because the design of the external database will differ from the CMS's own I have decided the best way forward is to use two databases and force the CMS to use the external to read user information (cannot write to) and a local for everything else the CMS needs to do (read + write). Is this feasible with these Drupal or ExpressionEngine? Ideally I need to be able to use hooks as I do not wan't to modify core CMS files. Sifting through the docs I am not able to find what I would hook into for ether CMS. (Note: I know it is possible, but I want to know if it's feasible). Finally if there is a better way of handling this situation please also chime in. Perhaps there is something at the database level to reference a field or table in an external database? I'm clutching at straws someone can point me in the right direction I'm sure.

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  • how to make a software and preserve database integrity and correctness and please help confused

    - by user287745
    i have made an application project in vs 08 c#, sql server from vs 08. the database has like 20 tables and many fields in each have made an interface for adding deleting editting and retrieving data according to predefined needs of the users. now i have to 1) make to project in to a software which i can deliver to professor. that is he can just double click the icon and the software simply starts. no vs 08 needed to start the debugging 2) the database will be on one powerful computer (dual core latest everything win xp) and the user will access it from another computer connected using LAN i am able to change the connection string to the shared database using vs 08/ debugger whenever the server changes but how am i supposed to do that when its a software? 3)there will by many clients am i supposed to give the same software to every one, so they all can connect to the database, how will the integrity and correctness of the database be maintained? i mean the db.mdf file will be in a folder which will be shared with read and write access. so its not necessary that only one user will write at a time. so is there any coding for this or? please help me out here i am stuck do not know what to do i have no practical experience, would appreciate all the help thank you

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  • How can I sync a database driven website to a different server

    - by tbrandao
    I have a website using cPanel on a dedicated account, I would like to be able to automatically sync the website to a second hosting company or perhaps to a local (in house ) server. Basically this is a type of replication. The website is database driven (MySQL), so Ideally it would sync everything (content, database, emails etc.) , but most importantly is syncing the website files and its database. I'm not so much looking for a fail-over solution as an automatic replication solution, so if the primary site (Server) goes off-line, I can manually bring up the replicated site quickly. I'm familiar with tools like unison and rsync, but most of these only sync file(s) and do not do too well with open database connections.

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  • Windows Mobile local database

    - by ThePower
    Hi, I'm writing an application for windows mobile 6 and above that requires a local database. I was wondering if anyone has any experience with database hosting on windows mobile and which database management system would be most suitable for development. Thanks in advance, Lloyd

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  • Why does this article state that graduate education liberate one from concerns like the efficiency of hardware-based integers?

    - by kadaj
    Quoting The Evolution of Haskell Programmer, graduate education tends to liberate one from petty concerns about, e.g., the efficiency of hardware-based integers What exactly does this suggest? Is it that after graduation, one gets more interested in abstract ideas so much that he does not think hardware is relevant? Or that hardware is also abstracted and one is more interested in algorithms? I am trying to understand on what grounds the sentence is based.

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  • Visual Studio 2008 (C#) with SQL Compact Edition database error: 26

    - by Tommy
    A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) I've created a SQL compact database, included it in my application, and can connect to the database fine from other database editors, but within my application im trying using (SqlConnection con = new SqlConnection(Properties.Settings.Default.DatabaseConnection)) { con.Open(); } the connection string is Data Source=|DataDirectory|\Database.sdf I'm stumped, any insight?

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  • how to tackle a custom forms database

    - by Neil Hickman
    I'm currently researching a project for the place that I work in. We are trying to create a system that will allow forms to be set up dynamically from a database. My question is what database structure would best suit something like this? I currently have a structure of: forms_form forms_formfields forms_formdata I don't think this is the most appropriate layout for this. Basically to make is make sense I need to be able to make a form within the database that can have infinite fields all customized and have the data when submitted stored in the database.

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  • Designing communications for extensibility

    - by Thomas S.
    I am working on the design stages of an application that will a) collect data from various sources (in my case that's scientific data from serial ports), keeping track of the age of the data, b) generate real-time statistics (e.g. running averages) c) display, record, and otherwise handle the data (and statistics). I anticipate that I will be adding both data producers and consumers over time, and would like to design this application abstractly so that I will be able to trivially add functionality with a small amount of interface code. What I'm stumbling on is deciding what communication infrastructure I should use to handle the interfaces. In particular, how should I make the processed data and statistics available to multiple consumers? Some things I've considered: Writing to several named pipes (variable number). Each consumer reads from one of them. Using FUSE to make a userspace filesystem where a read() returns the latest line of data even if another process has already read it. Making a TCP server, and having consumers connect and request data individually. Simply writing the consumers as part of the same program that aggregates the data. So I would like to hear your all's advice on deciding how to interface these functions in the best way to keep them separate and allow room for extenstions.

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  • I have data that sends in "bursts" of 100 records with a significant delay. How do I structure my classes for multithreading?

    - by makerofthings7
    My datasource sends information in 100 batches of 100 records with a delay of 1 to 3 seconds between batches. I would like to start processing data as soon as it's received, but I'm not sure how to best approach this. Some ideas I've been playing with include: yield Concurrent Dictionary ConcurrentDictionary with INotifyProperyChanged Events etc. As you can see I'm all over the place, and would appreciate some tested guidance on how to approach this

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  • Maintenance tool for Application Database

    - by Thierry
    Hello ! Does anybody know about a good tool which help maintaining the database of an application ? I'm working on an application which uses a database (Microsoft Sql Server). When a development requires to change something in the database (e.g., structure, data migration...), we create a script (Transact-SQL script) and add it into our revision control tool (subversion - that tool also contains our code). Each script must add a line in a log table to keep a trace of all the scripts that have been ran into a database. In order to build a database for our application, one needs to run all scripts ordered by their creation date. I'm not really happy with this technique notably because it make application migration a bit hard. If we want to install a new version of the application somewhere, e.g., migrate from version 1.3 to 2.1, we must get all the scripts between these two versions. Then run them and ensure that everything is done in a transaction... For sure we could built home-made tools to help but I wonder if some tools already exists to do that kind of job.

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