Search Results

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

Page 364/1635 | < Previous Page | 360 361 362 363 364 365 366 367 368 369 370 371  | Next Page >

• "No database selected" even when db clearly selected

  - by Someone

  One of my webpages gets a recurring error: "No database selected", even though the DB is selected. Right about now it's a 50-50 chance whether the page will load just fine, or whether I receive this error. After one or two reloads, the page works again. I am including the exact same connection file on my other pages, and I don't have this problem. What could be the cause of this? I'm using ensim pro for webhosting. TIA.

  Read the article

• Is there a standard practice for storing default application data?

  - by Rox Wen

  Our application includes a default set of data. The default data includes coefficients and other factors that are unlikely to ever change but still need to be update-able by the user. Currently, the original default data is stored as a populated class within the application. Data updates are stored to an external XML file. This design allows us to include a "reset" feature to restore the original default data. Our rationale for not storing defaults externally [e.g. XML file] was to minimize the risk of being altered. The overall volume of data doesn't warrant a database. Is there a standard practice for storing "default" application data?

  Read the article

• Surrogate key for date dimension?

  - by Navin

  There are 2 school of thoughts : Use surrogate key preferbly in the format of YYYYMMDD as this will always be sequential. Eliminate Date dimension surrogate key and use actual date instead. My Questions to experts on dimension modeling are : 1> Which design would you prefer and why ? 2> How should we handle unknown values in each of the cases, Can we simply place NULL in Fact table for unknown dates as Foreign Key can be NULL (if no why)? 3> If we need to partition fact table on date column ,how would we achieve that in case 1. I am inclined towards using actual date and using NULL to represent UNKNOWN dates in fact table , as date related validation on fact can be done without need to look in to dimension table.

  Read the article

• Parsing a CSV File to a Rails Database

  - by Schroedinger

  G'day guys, I'm using fasterCSV and a rake script to parse a csv with about 30 columns into my rails db for a 'Trade' item. The script works fine when all of the values are set to strings, but when I change it to a decimal, int or other value, everything goes to hell. Wondering if fasterCSV has built in int etc parsing or whether I'll have to manage these within my model. Basically, I'm given a giant amount of trades data, need to import it, and then need to provide feedback with say the average trade volume, the times, etc. I understand I can do that all with the wonderful records provided to me by activeRecord but wondered if there was an easier way to populate a rather large Database with a given CSV? Several of the fields don't have values for certain rows, fasterCSV seems to work perfectly when they're all strings, but not when I try to get decimal or other.

  Read the article

• MySQL JDBC date issues with database server in different timezone

  - by Somatik

  I have a database server in "Europe/London" time zone and my web server in "Europe/Brussels". Since it is summer time now my application server has a 2 hour difference. I created a test to reproduce my issue: Query q = JPA.em().createNativeQuery("SELECT UNIX_TIMESTAMP(startDateTime) FROM `Event` WHERE `id` =574"); BigInteger unix = (BigInteger) q.getSingleResult(); System.out.println(unix + "000 UNIX_TIMESTAMP to BigInteger"); Query q2 = JPA.em().createNativeQuery("SELECT startDateTime FROM `Event` WHERE `id` =574"); Timestamp o = (Timestamp) q2.getSingleResult(); System.out.println(o.getTime() + " Timestamp"); The startDateTime column is defined as 'datetime' (but same issue with 'timestamp') The output I am getting is this: 1340291591000 UNIX_TIMESTAMP to BigInteger 1340284391000 Timestamp Reading java date objects results in a shift in time zone, how do I fix this? I would expect the jdbc driver to just set the "unix time" value it gets from the server in the Date object. (a proper solution should work with any timezone combination, not only for db in GMT)

  Read the article

• What is the most efficient way to store a mapping "key -> event stream"?

  - by jkff

  Suppose there are ~10,000's of keys, where each key corresponds to a stream of events. I'd like to support the following operations: push(key, timestamp, event) - pushes event to the event queue for key, marked with the given timestamp. It is guaranteed that event timestamps for a particular key are pushed in sorted or almost sorted order. tail(key, timestamp) - get all events for key since the given timestamp. Usually the timestamp requests for a given key are almost monotonically increasing, almost synchronously with pushes for the same key. This stuff has to be persistent (although it is not absolutely necessary to persist pushes immediately and to keep tails with pushes strictly in sync), so I'm going to use some kind of database. What is the optimal kind of database structure for this task? Would it be better to use a relational database, a key-value storage, or something else?

  Read the article

• One executable with cmd-line params or just many satellite executables?

  - by Nikos Baxevanis

  I design an application back-end. For now, it is a .NET process (a Console Application) which hosts various communication frameworks such as Agatha and NServiceBus. I need to periodically update my datastore with values (coming from the application while it's running). I found three possible ways: Accept command line arguments, so I can call my console app with -update. On start up a background thread will periodically invoke the update method. Create an updater.exe app which will do the updates, but I will have code duplication since in some way it will need to query the data from the source in order to save it to the datastore. Which one is better?

  Read the article

• How to control the memory size of continuously running windows service?

  - by Snowill

  Hi, I have created a windows service which is continuously polling a database. For this purpose i have a timer in place. Ever time i am querying a database table i open a connection and close it immediately after my work is done. Right now i am doing this every 20 seconds for testing purpose, but later this time might increase to 5 - 10 minutes. What happens is everytime the database table is polled there is an increase of 10-12 KB in the size of the memory of the service running. This i can see in the task manager. Is there any way to control this.

  Read the article

• What are some best practices for making sure your .NET code will scale well?

  - by billmaya

  Last week I interviewed for a position at a TripleA MMORPG game company here in NE. I didn't get the job but one of the areas that came up during the interview was the about the scalability of the code that you write and how it should be considered early on in the design of your architecture and classes. Sadly to say I've never thought very much about the scalability of the .NET code that I've written (I work with single user desktop and mobile applications and our major concerns are usually with device memory and rates of data transmission). I'm interested in learning more about writing code that scales up well so it can handle a wide range of remote users in a client server environment, specifically MMORPGs. Are there any books, web sites, best practices, etc. that could get me started researching this topic?

  Read the article

• MySQL or SQL Server

  - by user203708

  I'm creating an application that I want to run on either MySQL or SQL Server (not both at the same time) I've created two PHP classes DatabaseMySQL and DatabaseSQLSVR and I'd like my application to know which database class to use based on a constant set up at install. define(DB_TYPE, "mysql"); // or "sqlsrv" I'm trying to think of the best way to handle this. My thought is to do an "if else" wherever I instantiate the database: $db = (DB_TYPE == "mysql") ? new DatabaseMySQL : new DatabaseSQLSVR; I know there has to be a better way of doing this though. Suppose I want to add a third database type later; I'll have to go and redo all my code. Yuk!! Any help would be much appreciated. Thank

  Read the article

• Wait for tasks to get completed in threadpool.

  - by Alien01

  Hello I have created a thread pool in C++ which stores all tasks in a queue. Thread pool start n number of threads which takes tasks from queue , process each task and then delete tasks from queue. Now , I want to wait till all tasks get completed. Checking for empty queue for completion of tasks may not work as , task can be given to each thread and queue can be emptied but still the tasks can in processing mode. I am not getting idea how to wait for all the tasks completion.This is a design problem. Any suggestions?

  Read the article

• Are there any e-commerce websites that use NoSQL databases

  - by Saif Bechan

  I have read a lot lately about 'NoSQL' databases such as CouchDB, MongoDB etc. Most of the websites I have seen using this are mainly text based websites such as The New York Times and Source forge. I was wondering if you could apply this to websites where payment is a huge issue. I am thinking of the following issues: How well can you secure the data Do these system provide an easy backup/restore machanism How are transactions handled commit/rollback I have read the following articles that cover some aspects: Can I do transactions and locks in CouchDB? Pros/Cons of document based database vs relational database In these posts the aspect of transactions if covered. However the questions of security and backups is not covered. Can someone shed some light on this subject? And if possible, does anyone know of some e-commerce websites that have successfully implemented the document based database.

  Read the article

• error in mysql syntax in vb.net

  - by user225269

  I get this error, while I'm testing the code below: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '[student](ID, LASTNAME, FIRSTNAME, SCHOOL) VALUES ('333', 'aaa', 'aaa', 'aaa')' at line 1 I just recycled the code that I used in manipulating ms sql database. So the syntax must be wrong. What might be the correct syntax for adding records into mysql database? Here is my current code: idnum = TextBox1.Text lname = TextBox2.Text fname = TextBox3.Text skul = TextBox4.Text Using sqlcon As New MySqlConnection("Server=localhost; Database=testing;Uid=root;Pwd=nitoryolai123$%^;") sqlcon.Open() Dim sqlcom As New MySqlCommand() sqlcom.Connection = sqlcon sqlcom.CommandText = "INSERT INTO [student](ID, LASTNAME, FIRSTNAME, SCHOOL) VALUES (@ParameterID, @ParameterLastName, @ParameterFirstName, @ParameterSchool)" sqlcom.Parameters.AddWithValue("@ParameterID", TextBox1.Text) sqlcom.Parameters.AddWithValue("@ParameterLastName", TextBox2.Text) sqlcom.Parameters.AddWithValue("@ParameterFirstName", TextBox3.Text) sqlcom.Parameters.AddWithValue("@ParameterSchool", TextBox4.Text) sqlcom.ExecuteNonQuery() End Using Please help, thanks

  Read the article

• SQL Server: query database user roles for all databases in server

  - by atricapilla

  I would like to make a query for database user roles for all databases in my sql server instance. I modified a query from sp_helpuser: select u.name ,case when (r.principal_id is null) then 'public' else r.name end ,l.default_database_name ,u.default_schema_name ,u.principal_id from sys.database_principals u left join (sys.database_role_members m join sys.database_principals r on m.role_principal_id = r.principal_id) on m.member_principal_id = u.principal_id left join sys.server_principals l on u.sid = l.sid where u.type <> 'R' How can I modify this to query from all databases? What is the link between sys.databases and sys.database_principals?

  Read the article

• INET_ATON() and INET_NTOA() in PHP?

  - by blerh

  I want to store IP addresses in my database, but I also need to use them throughout my application. I read about using INET_ATON() and INET_NTOA() in my MySQL queries to get a 32-bit unsigned integer out of an IP address, which is exactly what I want as it will make searching through the database faster than using char(15). The thing is, I can't find a function that does the same sort of thing in PHP. The only thing I came across is: http://php.net/manual/en/function.ip2long.php So I tested it: $ip = $_SERVER['REMOTE_ADDR']; echo ip2long($ip); And it outputs nothing. In the example they gave it seems to work, but then again I'm not exactly sure if ip2long() does the same thing as INET_ATON(). Does someone know a PHP function that will do this? Or even a completely new solution to storing an IP address in a database? Thanks.

  Read the article

• View artifacts leaking into the model of MVC

  - by Jono

  In an ASP.NET MVC application (which has very little chance of having its view technology ported to something non-HTML, but whose functional requirements evolve weekly,) how much HTML should ideally be allowed to be directly represented in the Model? I might come across as a design bigot for this, but I regard it as bad practice to allow any view constructs to "leak" into the model in an MVC application (and vice versa). For example, a Model that represents an item you're about to purchase should know nothing about the HTML check box that says "add giftwrap/message", nor should it know about any HTML drop down lists for payment card types. Conversely the View shouldn't be doing work like figuring out button text by translating keys into values (by looking in resource files.)

  Read the article

• Large tables of static data with DBGhost

  - by Paulo Manuel Santos

  We are thinking of restructuring our database development and deployment processes by using DBGhost, we want to move away from the central development database and bring the database to the source control. One of the problems we have is a big table with static data (containing translated language strings), it has close to 200K rows. I know that our best solution is to move these stings into resource files, but until we implement that, will DbGhost be able to maintain all this static data and generate our development and deployment databases in a short time? And if not is there a good alternative to filling up this table whenever we need to?

  Read the article

• Any ideas for developing a Risc Processor friendly string allocator?

  - by Richard Fabian

  I'm working on some tools to enable high throughput data-oriented development, and one thing that I've not got an immediate answer for is how you go about allocating strings quickly. On risc processors you've got another problem of implementation that the CPU doesn't like branching, which is what I'm trying to minimise or avoid. Also, cache coherence is important on most CPUs, so that's gotta be influential in the design too. So, how would you go about reducing the overhead for a generic string allocator? Sometimes it's easier to solve a more explicit problem, so any ideas for string sizes of 5-30?

  Read the article

• Top tips for designing GUIs?

  - by oxbow_lakes

  A while back I read (before I lost it) a great book called GUI Bloopers which was full of examples of bad GUI design but also full of useful tidbits like Don't call something a Dialog one minute and a Popup the next. What top tips would you give for designing/documenting a GUI? It would be particularly useful to hear about widgets you designed to cram readable information into as little screen real-estate as possible. I'm going to roll this off with one of my own: avoid trees (e.g. Swing's JTree) unless you really can't avoid it, or have a unbounded hierarchy of stuff. I have found that users don't find them intuitive and they are hard to navigate and filter. PS. I think this question differs from this one as I'm asking for generalist tips

  Read the article

• Send through Email, or store in database?

  - by user156814

  I have wondered when it is best to send an email, and when its best to store data in a database/log file. Everytime a user wants to contact me or inform me of soething, I suppose an email is best.. but is an email always preferred over other ways, and in what cases. Possible reasons for being contacted I can think of are questions, suggestions, feedback, reporting abuse, advertising, etc... I assume email, "why add unnecessary things to the DB?", but I figure data in DB would be a lot easier to manage. Whats the better/best way to be informed of things like this.. What is the best way for you (webmaster) to be informed of something by users? through email, or some other way

  Read the article

• creational pattern for instances depending on multiple subclass instances

  - by markusw

  I have a problem, for that I was not able to identify a suitable design pattern. I want to create instances depending on a given type that has been passed to a factory method. What I am doing until now is the following: T create(SuperType x) { if (x instanceof SubType1) { // do some stuff and return a new SubType extends T } else if (x instanceof SubType2) { // do some stuff and return a new SubType extends T } else if ... } else { throw new UnSupportedOperationException("nothing defined for " + x); } } It seems not to be best pratice for me. Has anybody an idea how to solve this in a better way?

  Read the article

• How to insert an integer into a database through command prompt

  - by jpavlov

  I am trying to insert a integer into a database in C# using the code below, but everytime I run the compiler informs me that my integer is not a valid column "Invalid Column Name UserID" Does anyone have any insight on this? Thanks. Console.WriteLine("Please enter a new User Id"); string line = Console.ReadLine(); int UserID; if (int.TryParse(line, out UserID)) { Console.WriteLine(UserID); Console.ReadLine(); } //Prepare the command string string insertString = @"INSERT INTO tb_User(ID,f_Name, l_Name) VALUES (UserID,'Ted','Turner')";

  Read the article

• What do you do before starting on a project?

  - by hahuang65

  I'm still a pretty new project, and I haven't really worked on any large projects yet. However a few projects for school has shown me something I have never really thought of before. Pre-Project planning. One project we ran into a huge problem at the very last minute, and the other project was not divided up between partners very evenly, such that all the work was actually done at the end. So my question to everyone here is: How do you plan out the project beforehand? Please try to cover the following: Design (draw out UI by hand, UMLs, etc.) Division of Labor Timeline (especially how you estimate how much time is needed for certain things) and anything else you can think of. Thanks for all the help!

  Read the article

• are fixtures loaded when using the sql dump to create a test database

  - by Josh Moore

  Because of some non standard table creation options I am forced to use the sql dump instead of the standard schema.rb (i.e. I have uncommented this line in the environment.rb config.active_record.schema_format = :sql). I have noticed that when I use the sql dump that my fixtures do not seem to be loaded into the database. Some data is loaded into it but, I am not sure where it is coming from. Is this normal? and if it is normal can anybody tell me where this other data is coming from?

  Read the article

• A question about indexes regarding to the gain of inserts & updates in database

  - by Mestika

  Hi, I’m having a question about the fine line between the gain of an index to a table there is growing steadily in size every month and the gain of queries with an index. The situation is, that I’ve two tables, Table1 and Table2. Each table grows slowly but regularly each month (with about 100 new rows for Table1 and a couple of rows for Table2). My concrete question is whether to have an index or to drop it. I’ve made some measurement that an covering index on Table2 improve my SELECT queries and some rather much but again, I’ve to consider the pros and cons but having a really hard time to decide. For Table1 it might not be necessary to have an index because the SELECT queries there is not that common. I would appreciate any suggestion, tips or just good advice to what is a good solution. By the way, I’m using IBM DB2 version 9.7 as my Database system Sincerely Mestika

  Read the article

< Previous Page | 360 361 362 363 364 365 366 367 368 369 370 371  | Next Page >