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  • designing database tables using JDBC

    - by Noona
    I am creating a users table using JDBC and mysql, each user has a permissions list that comprises Integer values, I am wondering if I should use an array for storing these values and then have only 1 record for this user in the table, or simply create a new table that comprises 2 columns: user ID and permissions, and then have multiple records for each user that specify the user name in one columns and one permission value in the second column, the second option seems to be redundant since a permission value is a simple object that isn't associated with any other objects (like a student and courses list for example, because the course is associated with many other objects, like grade, teacher, etc, so in this case it is natural to have multiple records), but the first one seems to be a bit unnatural to me, so if someone has experience with these things and direct me? thanks

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  • Voting Script, Possibility of Simplifying Database Queries

    - by Sev
    I have a voting script which stores the post_id and the user_id in a table, to determine whether a particular user has already voted on a post and disallow them in the future. To do that, I am doing the following 3 queries. SELECT user_id, post_id from votes_table where postid=? AND user_id=? If that returns no rows, then: UPDATE post_table set votecount = votecount-1 where post_id = ? Then SELECT votecount from post where post_id=? To display the new votecount on the web page Any better way to do this? 3 queries are seriously slowing down the user's voting experience Edit In the votes table, vote_id is a primary key In the post table, post_id is a primary key. Any other suggestions to speed things up?

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  • Connecting data to a GUI - OOP

    - by tau
    I have an application with several graphs and tables on it. I worked fast and just made classes like Graph and Table that each contained a request object (pseudo-code): class Graph { private request; public function setDateRange(dateRange) { request.setDateRange(dateRange); } public function refresh() { request.getData(function() { //refresh the display }); } } Upon a GUI event (say, someone changes the date range dropdown), I'd just call the setters on the Graph instance and then refresh it. Well, when I added other GUI elements like tables and whatnot, they all basically had similar methods (setDateRange and other things common to the request). What are some more elegant OOP ways of doing this? The application is very simple and I don't want to over-architect it, but I also don't want to have a bunch of classes with basically the same methods that are just routing to a request object. I also don't want to set up each GUI class as inheriting from the request class, but I'm open to any ideas really.

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  • Sybase PowerDesigner Change Many (Find/Replace/Convert) Data Item's Data Types

    - by Andy
    Hello, I have a relatively large Conceptual Data Model in PowerDesigner. After generating a Physical Data Model and seeing the DBMS data types, I need to update all of data types(NUMBER/TEXT) for each data item. I'd like to either do a find/replace within the Conceptual Data Model or somehow map to different data types when creating the Physical Data Model. Ex. Change the auto conversion of Text - Clob, to Text - NVARCHAR(20). Thanks!

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  • Compressing a database to a single file?

    - by Assimilater
    Hi all. In my contact manager program I have been storing information by reading and writing comma delimited files for each individual contact, and storing notes in a file for each note, and I'm wondering how I could go about shrinking them all into one file effectively. I have attempted using data entry tools in the visual studio toolbox and template class, though I have never quite figured out how to use them. What would be especially convenient is if I could store data as data type IOwner (a class I created) as opposed to strings. I'd also need to figure out how to tell the program what to do when a file is opened (I've noticed in the properties how to associate a file type with the program though am not sure how to tell it what to do when it's opened). Edit: How about rephrasing the question: I have a class IContact with various properties some of them being lists of other class objects. I have a public list of IContact. Can I write Contacts as List(Of IContact) to a file as opposed to a bunch of strings? Second part of the question: I have associated .cms files with my program. But if a user opens the file, what code should the program run through in an attempt to deal with the file? This file is going to contain data that the program needs to read, how do I tell it to read a file when the program is opened vicariously because the file was opened? Does this make the question clearer?

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  • Is there a prefered way to specify a text column in SQLite?

    - by JannieT
    Since the SQLite engine will not truncate the data you store in a text column, is there any advantage in being specific with column sizes when you define your schema? Would anyone prefer this: CREATE TABLE contact( id INTEGER PRIMARY KEY, name VARCHAR(45), title VARCHAR(10) ); over this: CREATE TABLE contact( id INTEGER PRIMARY KEY, name TEXT, title TEXT ); Why? Are there advantages to not being specific?

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  • Binded click loses context of my Class. JS

    - by Fabiano PS
    Hi, I have this problem that I probably understand but don't know how to handle, if there is a way. I have a class simplified as this: function DrawingTable(canvas_id){ this.canvas_id = canvas_id; bind_events() function bind_events(){ $(get_canvas()).click(function(e){ var canvas = get_canvas() //works do_something_in_the_instance_who_called_click() } function get_canvas(){return document.getElementById(canvas_id)} function do_something_in_the_instance_who_called_click(){ alert(this.canvas_id) //fail! } } Because when the click() is invoked for what it looks this is not inside the instance anymore, but I need to change atributes from there.. is there a way, given that may be multiple instances? I don't really know how but the get_canvas() works :) I'm using jQuery but likely not relevant

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  • What is a mantainable way of saving "star rating" in a database?

    - by Montecristo
    I'll use the jQuery plugin for presenting the user with a nice interface The request is to display 5 stars, up to a total score of 10 (2 points per star). By now I thought about using 7/10 as a format for that value, but what if at some point in the future I'll receive a request like We would like to give users more choice, let's increase the total score to 20 (so that each star contributes with a maximum of 4 points) I'll end up with a table with mixed values for the "star rating" column: some will be like 7/10 while others will be like 14/20. Is it ok for you to have this difference in the database and deal with it in the logic layer to have it consistent? Or is preferred another way so that querying the table will not result in inconsistent results outside the application? Maybe floating point values could help me, is it better to store that value as a number less than or equal to one? So in each of the two examples the resulting value stored in the database would be 0,7, as a number, not a varchar, which can be queried also outside the application. What do you think?

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  • user height and weight in sql

    - by Samuel
    We are planning to capture a user's height and weight and am looking for ideas on representing them in sql. I have the following questions in mind weight can be expressed in kilograms and grams and height in meters and centimeters, so should I capture them as a BigDecimal with an appropriate precision and scale or capture them as vanilla strings and do the manipulation in the user interface. Note: I am planning to capture the kilograms and grams separately in the user interface. should the metric of measurement be part of the sql (i.e. the end user might want to view this information in pounds, inches according to his preference) OR Should I just support kilograms / meters in the database and do the conversion while showing this in the user interface

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  • Doubleton Pattern Implementation

    - by Pierreten
    I'm leveraging the Doubleton Pattern from this link http://www.codeproject.com/KB/architecture/designpattern_doubleton.aspx in my own code. I think it makes things a lot easier since the Singleton only provides one instance, but I get two with this pattern. I was wondering if it would make sense to have it implement an interface so I can inject it into my domain layer.

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  • What's the simplest way to make a scrollable list of controls with labels?

    - by Jon Cage
    Using C++/CLI and Windows Forms, I'm trying to make a simple scrollable list of labelled text controls as a way of displaying some data fields. I'm having trouble making a TableLayoutPanel scrollable - every combination of properties I've tried seems to result in some really peculiar side effects. So I have two questions: Is this the best way to do it. If it is a reasonable approach, what magic combination of settings should I apply to the table layout panel to make it play ball?

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  • Should I Split Tables Relevant to X Module Into Different DB? Mysql

    - by Michael Robinson
    I've inherited a rather large and somewhat messy codebase, and have been tasked with making it faster, less noodly and generally better. Currently we use one big database to hold all data for all aspects of the site. As we need to plan for significant growth in the future, I'm considering splitting tables relevant to specific sections of the site into different databases, so if/when one gets too large for one server I can more easily migrate some user data to different mysql servers while retaining overall integrity. I would still need to use joins on some tables across the new databases. Is this a normal thing to do? Would I incur a performance hit because of this?

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  • How to update SQL Server database from multiple data sources for ASP.Net MVC 4 application

    - by shaz
    I have 10+ SQL Server databases, from where I would use one table from each database to display information using the application that I am creating. For instance, DB1, DB2....DB10. NewDB (Account, Country, Costcenter....etc.). I have started with creating a new database which would contain all the information from all those 10+ databases. However, I am confused in many cases. First of all what process should I follow? Shall I create a table (in new database) with the same structure as the actual data source and insert data from actual data source to new database? Should I be doing this on the DBMS? If so, is it some scripting? (hint expected since very new to this) I am creating a report generation application which has 10+ data sources. I need some hint which way should I proceed? Thanks for advice/help in advance.

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  • Implementing a 'many-to-many' database

    - by Raven Dreamer
    Greetings, stack*overflow* In my database, I already have one table, 'contacts' that contains records of individual people. I also have several other tables in my database which represent "skill sets" that contain records denoting a particular skill. 1) Am I correct in plotting this as a "many-to-many" relationship? (each contact can have multiple skill sets, and each skill set can belong to multiple contacts) 2) I'm new to databases -- do I want to link the tables? 3) Is there a way to implement this in my program (C# + windows forms) such that for any given record in the 'contacts' table, either the names of all associated 'skill set' tables or all the 'skill' records associated with the 'contact' record could be retrieved? (Database is located on SQL Server Express 2008)

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  • How to choose between UUIDs, autoincrement/sequence keys and sequence tables for database primary keys?

    - by Tim
    I'm looking at the pros and cons of these three primary methods of coming up with primary keys for database rows. So assuming I am using a database that supports more than one of these methods, is there a simple heuristic to determine what the best option would be for me? How do considerations such a distributed/multiple masters, performance requirements, ORM use, security and testing have on the choice? Any unexpected drawbacks that one might run into?

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  • When NOT to use MVVM?

    - by Vitalij
    I have started using MVVM pattern recently. I have had several projects where I used it and with every new one, I start to see that it will fit great within that new project. And now I start to ask myself are there situation when it's better NOT to use MVVM. Or is it such a nice pattern which you can use anywhere? Could you please describe several scenarios where MVVM wouldn't be the best choice?

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  • How should I build a simple database package for my python application?

    - by Carson Myers
    I'm building a database library for my application using sqlite3 as the base. I want to structure it like so: db/ __init__.py users.py blah.py etc.py So I would do this in Python: import db db.users.create('username', 'password') I'm suffering analysis paralysis (oh no!) about how to handle the database connection. I don't really want to use classes in these modules, it doesn't really seem appropriate to be able to create a bunch of "users" objects that can all manipulate the same database in the same ways -- so inheriting a connection is a no-go. Should I have one global connection to the database that all the modules use, and then put this in each module: #users.py from db_stuff import connection Or should I create a new connection for each module and keep that alive? Or should I create a new connection for every transaction? How are these database connections supposed to be used? The same goes for cursor objects: Do I create a new cursor for each transaction? Create just one for each database connection?

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  • Correct handling of return data

    - by Serhiy
    Hello, I have a question related to correct handling of returns of the DAO library I'm writing for one project. This library probably is going to be used by another people and I want to do it correctly. So I would like to know, how I should deal with return statements of the functions of my DAO. Example 1 I have function to getCustomer which should return String. In case query doesn't return any result should I return null, empty string or throw some kind of Exception? Example 2 I have function getCutomerList which return ArrayList. In case query doesn't return any result should I return null, empty ArrayList or throw some Exception? Example 3 Some sql exception was detected, what should I do: throw exception or do try..catch of the block where it can occur? What is the "good" practice or "best" practice to apply in my case? Thanks on advance, Serhiy.

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  • How I can Optimize this mySQL transaction within java code?

    - by worldpython
    Dear All, I am new to MySql database. I've large table(ID,...). I select ID frequently with java code and.And that make a heavy load on transaction select from tableName where ID=someID notes: 1.Database could be 100,000 records 2.I can't cache result 3.ID is a primary key 4.I try to optimize time needed to return result from query. Any ideas for optimization ? thanks in advance

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  • What is the role of the Router Object in MVC based frameworks

    - by Saif Bechan
    In most MVC based framework I see a router object. If I look at it splits up the uri and decides what controller should be used, and which action should be fired. Even though this makes a lot of sense, I can not give this a place in the MVC patern. Is splitting up the uri not the job of the controller. And then the controller should just decide which class and function to run.

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  • Unable to find the cause of an annoying content gap in my HTML/CSS?

    - by user1472747
    I'm quite new to CSS / HTML, and can't find the cause of this little bugger. I want it gone, so that the banner and the nav bar touch each other. Any help is greatly appreciated!! Here is the code for the site. I took out some of the irrelevant code. <!DOCTYPE html> <html> <!-- *****CSS CODE START*****--> <style type="text/css"> #container { margin: 0 auto; width: 900px; background: #fff; } #header { margin-top: 0px; } #header h1 { margin: 0; } #navigation { float: left; width: 900px; background: #333; } #navigation ul { margin: 0; padding: 0; } #navigation ul li { list-style-type: none; display: inline; } #navigation li a { display: block; float: left; padding: 5px 10px; color: #fff; text-decoration: none; border-right: 1px solid #fff; } #navigation li a:hover { background: #383; } #content-container { float: left; width: 900px; background: #fff url(/wp-content/uploads/layout-two-fixed-background.gif) repeat-y 100% 0; } #content { clear: left; float: left; width: 619px; height: 720px; padding: 10px 0; margin: 0 0 0 0px; display: inline; overflow: auto; } #content h2 { margin: 0; color: #003D5D; padding:10px; } #contentBody { padding:10px; font-size:22px; } #aside { float: right; width: 280px; padding: 20px 0; margin: 0 0px 0 0; display: inline; background: #cccccc; height: 700px; border-left: 1px solid #333 ; } #aside h3 { margin: 0 20px; color: #003D5D; font-family: Times New Roman; } #asideText { margin: 0 20px; font-family: Times New Roman;} #footer { clear: both; background: #ccc; text-align: right; padding: 5px; height: 1%; border-top: 1px solid #333 ; } </style> <!-- *****CSS CODE END***** --> <!-- *****HTML CODE START***** --> <body> <div id="container"> <div id="header"> <img src = file:///Users/jduffy/Desktop/projectSite/banner1.jpg> </img> </div> <div id="navigation"> <ul> <li><a href="file:///Users/jduffy/Desktop/projectSite/home">Home</a></li> <li><a href="file:///Users/jduffy/Desktop/projectSite/theProject">The Project</a></li> <li><a href="file:///Users/jduffy/Desktop/projectSite/Pictures">Pictures</a></li> <li><a href="file:///Users/jduffy/Desktop/projectSite/Contact">Contact us</a></li> </ul> </div> <div id="content-container"> <div id="content"> <h2> Page heading </h2> <div id="contentBody"> <p> home pagehome pagehome pagehome pagehome pagehome pagehome pagehome pagehome pagehome pagehome pagehome page home pagehome pagehome pagehome pagehome pagehome pagehome pagehome pagehome pagehome pagehome pagehome page home pagehome pagehome pagehome pagehome pagehome pagehome pagehome pagehome pagehome pagehome pagehome page </p> <p> test2 </p> <p> test3 </p> </div> </div> <div id="aside"> <div id="asideHeading"> <h3> Aside Heading </h3> </div> <div id="asideText"> <p> test5 </p> </div> </div> <div id="footer"> <text id="footerDate">0</text> </div> </div> </div> </body> <!-- *****HTML CODE END***** --> </html> <!-- *****JavaScript CODE START***** --> <script type="text/javascript"> /*date*/ var today = new Date(); document.getElementById("footerDate").innerHTML = today; </script> <!-- *****JavaScript CODE END***** -->

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  • Best practice for near reuse of model components?

    - by Chris Knight
    I have a requirement to use a Fund model in my code. It will contain a fund name and fund code. In the interest of reuse I've poked around the package containing the other models used and found an existing Fund model. However the issue here is that, in addition to fund name and code, it also contains an amount. Amount isn't directly relevant in my context. So, do I: 1) Use the existing Fund model as is, ignoring the setters/getters for fund amount. 2) Put a FundDescription interface onto the existing Fund model for accessing only the information I'm interested in. 3) Make a FundDescription base class from which the existing Fund model could now extend 4) Create a whole new seperate model since the two are slightly contextually different

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