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• Store data in Ruby on Rails without Database

  - by snowmaninthesun

  I have a few data values that I need to store on my rails app and wanted to know if there are any alternatives to creating a database table just to do this simple task. Background: I'm writing some analytics and dashboard tools for my ruby on rails app and i'm hoping to speed up the dashboard by caching results that will never change. Right now I pull all users for the last 30 days, and re arange them so I can see the number of new users per day. It works great but takes quite a long time, in reality I should only need to calculate the most recent day and just store the rest of the array somewhere else. Where is the best way to store this array? Creating a database table seems a bit overkill, and i'm not sure that global variables are the correct answer. Is there a best practice for persisting data like this? If anyone has done anything like this before let me know what you did and how it turned out.

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• Selecting pictures from database

  - by user1691618

  Okay guys, I need some help. I'm trying to design a page where a user can ask a question and upload up to 4 pictures. I have 2 database tables, questions and image_table. I have everything uploading correctly, so that's not my problem. What I am having trouble doing is selecting images from the image_table database that only correspond to that question. I can't figure out how to do this. Any help would be GREATLY appreciated.

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• How to store a 250mb database in an Offline Web App

  - by Couto

  Ok, maybe i'm not seeing the whole picture or something, but i kinda need a brainstorm. So the purpose is to make a webapp (HTML5, CSS, Javascript) that has to search on a 250mb database without any internet connection, so.. yes the database has to be on the client side. The hard part here is, this App has to work on an iPod or iPhone without internet connection. (An initial connection to download the App is ok), LocalStorage has a 5mb limit, couchDB would be great since they have an webapp easily accessed by Javascript (privacy concerns don't matter at this point), so i'm pretty much out of ideas.... Does anyone see an alternative, or solution for the purpose?

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• Iterating over a database column in Django

  - by curious

  I would like to iterate a calculation over a column of values in a MySQL database. I wondered if Django had any built-in functionality for doing this. Previously, I have just used the following to store each column as a list of tuples with the name table_column: import MySQLdb import sys try: conn = MySQLdb.connect (host = "localhost", user = "user", passwd="passwd", db="db") except MySQLdb.Error, e: print "Error %d: %s" % (e.args[0], e.args[1]) sys.exit (1) cursor = conn.cursor() for table in ['foo', 'bar']: for column in ['foobar1', 'foobar2']: cursor.execute('select %s from %s' % (column, table)) exec "%s_%s = cursor.fetchall()" % (table, column) cursor.close() conn.commit() conn.close() Is there any functionality built into Django to more conveniently iterate through the values of a column in a database table? I'm dealing with millions of rows so speed of execution is important.

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• Comparing textbox value to database

  - by simon

  HI ! I would like to compare values from a textbox with data from a table. I tried this code but i got the error that the input string was in the wrong format! code: string connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=save.mdb"; try { database = new OleDbConnection(connectionString); database.Open(); string queryString = "SELECT zivila.naziv,users.user_name FROM (obroki_save " + " LEFT JOIN zivila ON zivila.ID=obroki_save.ID_zivila) " + " LEFT JOIN users ON users.ID=obroki_save.ID_uporabnika " + " WHERE users.ID='" +Convert.ToInt16(id.iDTextBox.Text)+"'"; loadDataGrid(queryString); } catch (Exception ex) { MessageBox.Show(ex.Message); return; }

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• What is the most "database independent" way of creating a variable length text field in a database

  - by Thibaut Colar

  I want to create a text field in the database, with no specific size (it will store text of length unknown in some case) - the particular text are serialized simple object (~ JSON) What is the most database independent way to do this : - a varchar with no size specified (don't think all db support this) - a 'text' field, this seems to be common, but I don't believe it's a standard - a blob or other object of that kind ? - a varchar of a a very large size (that's inefficient and wastes disk space probably) - Other ? I'm using JDBC, but I'd like to use something that is supported in most DB (oracle, mysql, postgresql, derby, HSQL, H2 etc...) Thanks.

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• Database design to hold multiple iteration measurements

  - by Valder

  Hi All. I am new to sqlite and SQL in general. I am keen to switch from flat-files to sqlite for holding some measurement information. I need a tip on how to better layout the database, since I have zero experience with this. I have a ~10000 unique statistic counters that are collected before and after each test iteration. Max number of iterations are 10, though it could be less. I was thinking the following: CREATE TABLE stat_names(stat_id, stat_name); CREATE TABLE stats_per_iteration(stat_id, before_iter_1, after_iter_1, before_iter_2, after_iter_2, ...); stat_names table would hold mapping of a full counter to a uniq stat_id. stats_per_iteration table would hold mesurement data 1 + 10 * 2 columns. stat_names.stat_id = stats_per_iteration.stat_id OR maybe I should have a separate table for each iteration? Which would results in 1 + 10 tables in database. Thanks!

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• problems with inserting data in database

  - by jannes braet

  $message=$_POST['answer']; $message=nl2br($message); $message=strip_tags($message, '<p><a><b><i><strong><em><code><sub><sup><img><ul><ol><li>'); $message = mysql_real_escape_string($message); $user=$_SESSION['SESS_MEMBER_ID']; $qry="INSERT INTO forum_rules (message,author,date) VALUES ($message,$user,'".date("Y-m-d H:i:s")."')"; $result=mysql_query($qry) or die(mysql_error()); if (!$result) { echo "error inserting data into database"; } else { ... } this codes always outputs error inserting data into database and i don't see what i'm doing wrong. i hav also tried to do it without the date part but that didn't work tho. can someone please tell me what i'm doing wrong here

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• Suggestions on including free database products to include in an application - SQL Server Express or

  - by superartsy

  I am working on an enterprise level product that is designed around SQL Server Express and specifically its features (views, concurrent users, stored procedures, CASE and IF statements). Though we don't use any advanced SQL Server features, the database size limit of 4GB in the Express edition may up being a limitation. A work-around is that customers can move to more full-featured versions of SQL Server. The problem is that SQL Server Express deployment is not easy, and the installer size is huge. This is a major drawback for someone looking to try our product. You don't want end-users to not buy a product because the download is huge. Does anyone have any recommendations of a database that has a smaller footprint but all the features of Express and which can be migrated to express?

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• Array of an array (Database)

  - by Anne Mah Li'en

  I am trying to print out an array of an array from database Below are my codes. I am able to retrieve all the values from the first array. But error occurs when I am trying to retrieve the 2nd array from database. <% ArrayList<Questionnaire> allCategories =QuestionnaireController.getQuestionnaireByCategoryAll(); for(int i=0;i<allCategories.size();i++){ Questionnaire allCategoriesQuestionnaire=allCategories.get(i); out.println("<div class=\"silverheader\">" + "<a href= \"\">" + allCategoriesQuestionnaire.getCategory() + "</a>" + "</div>" + "<div class=\"submenu\">" + "ArrayList<Questionnaire> CategoriesSustainability =QuestionnaireController.getQuestionnaireByCategorySustainability();" + out.println(CategoriesSustainability.get(0).getCategory()); + "<br />" + "</div>"); } %>

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• Ruby on Rails: Best way to save search queries in a database

  - by Adam Templeton

  For a RoR app I'm helping develop, I need to save all search queries in a database so I can analyze them later. My plan right now is to create a Result model and table, and just save each search query's text in that table, along with a user's ID, the time, etc. However, the app has about 15,000 users, so I'm afraid the single table approach won't be super efficient when it comes time to parse that data. (The database is setup via MySQL, if that factors in at all.) Am I just being paranoid? Is there a Ruby gem that handles this sort of thing, or a better approach I could take? Any input would be appreciated.

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• Proper code but can't insert to database

  - by Dchris

  I have a Visual Basic project using Access database.I run a query but i don't see any new data on my database table.I don't have any exception or error.Instead of this the success messagebox is shown. Here is my code: Dim ID As Integer = 2 Dim TableNumber As Integer = 2 Dim OrderDate As Date = Format(Now, "General Date") Dim TotalPrice As Double = 100.0 Dim ConnectionString As String = "myconnectionstring" Dim con As New OleDb.OleDbConnection(ConnectionString) Try Dim InsertCMD As OleDb.OleDbCommand InsertCMD = New OleDb.OleDbCommand("INSERT INTO Orders([ID],[TableNumber],[OrderDate],[TotalPrice]) VALUES(@ID,@TableNumber,@OrderDate,@TotalPrice);", con) InsertCMD.Parameters.AddWithValue("@ID", ID) InsertCMD.Parameters.AddWithValue("@TableNumber", TableNumber) InsertCMD.Parameters.AddWithValue("@OrderDate", OrderDate) InsertCMD.Parameters.AddWithValue("@TotalPrice", TotalPrice) con.Open() InsertCMD.ExecuteNonQuery() MessageBox.Show("Successfully Added New Order", "Success", MessageBoxButtons.OK, MessageBoxIcon.Information) con.Close() Catch ex As Exception 'Something went wrong MessageBox.Show(ex.ToString) Finally 'Success or not, make sure it's closed If con.State <> ConnectionState.Closed Then con.Close() End Try What is the problem?

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• sports league database design

  - by John

  Hello, I'm developing a database to store statistics for a sports league. I'd like to show several tables: - league table that indicates the position of the team in the current and previous fixture - table that shows the position of a team in every fixture in the championship I have a matches table: Matches (IdMatch, IdTeam1, IdTeam2, GoalsTeam1, GoalsTeam2) Whith this table I can calculate the total points of every team based on the matches the team played. But every time I want to show the league table I have to calculate the points. Also I have a problem to calculate in which position classified a team in the last 10 fixtures cause I have to make 10 queries. To store the league table for every fixture in a database table is another approach, but every time I change a match already played I have to recalculate every fixture from there... Is there a better approach for this problem? Thanks

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• Connecting to the database in a Created Library - CodeIgniter

  - by Brogrammer

  I have a little issue right now and its bugging me, hopefully one of you guys will be able to help me out. Basically I'm creating a library to use in CodeIgniter and I'm getting this error: A PHP Error was encountered Severity: Notice Message: Undefined property: Functions::$db Filename: libraries/Functions.php Line Number: 11 The Database library is already on autoload aswell as my functions library: $autoload['libraries'] = array('database','session','encrypt','functions'); The Functions.php file is located in the application/libraries folder accordingly. Line number 11 consists of this: $this->db->where('username', $data); Not sure as to why the db is an undefined property?

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• Database that accesses a website.?

  - by Alec

  Hi Guys What application should I use that is able to automatically access a website to gather information? Basically I have a database that completes calculations for me; however I have to manually gather the parameters from a website and input these into my database. What I would like is have an application that will take my input say the name of a product, access the website, add this name into a search box on a website, complete the search and then extract the desired information from the web page returning the results to my application to complete the calculation thus presenting me with the result. This is a little out of my depth but I’m willing to learn no matter how complicated the software. Cheers for your help.

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• Preventing SQL injecting in a database class

  - by Josh

  I'm building a database class and thought it'd be a good idea to incorporate some form of SQL injection prevention (duh!). Here's the method that runs a database query: class DB { var $db_host = 'localhost'; var $db_user = 'root'; var $db_passwd = ''; var $db_name = 'whatever'; function query($sql) { $this->result = mysql_query($sql, $this->link); if(!$this->result) { $this->error(mysql_error()); } else { return $this->result; } } } There's more in the class than that but I'm cutting it down just for this. The problem I'm facing is if I just use mysql_real_escape_string($sql, $this->link); then it escapes the entire query and leads to a SQL syntax error. How can I dynamically find the variables that need to be escaped? I want to avoid using mysql_real_escape_string() in my main code blocks, i'd rather have it in a function. Thanks.

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• Database Insider Newsletter Helps Oracle Achieve Maggie Award Bid

  - by jenny.gelhausen

  The Database Insider team is honored to have our monthly newsletter help Oracle be nominated as a 2010 Maggie Award finalist. The Maggie Awards, known as the "Oscars" of the periodicals, are recognition of excellence to deserving individuals and companies whose work is deemed "The Best in the West" in a wide variety of publishing categories. The list of 2010 Maggie Award finalists is impressive and includes some past champions - so win or lose, the Database Insider team is thrilled to have helped Oracle achieve this finalist nomination in the category of Best Web E-Newsletter/Trade & Consumer. Thanks to all our faithful readers and subscribers. Haven't seen our newsletter yet? Read the latest Database Insider Newsletter edition. We invite you to subscribe and joins others receiving the Oracle Database Insider Newsletter in their Inbox, click here to register to start receiving your monthly Database Insider newsletter. Under Oracle Communications check the box next to: Oracle Database Insider - All about Oracle Database features and options including news and analysis, reviews, customer stories, events, offers, and more. Monthly. See sample. var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); try { var pageTracker = _gat._getTracker("UA-13185312-1"); pageTracker._trackPageview(); } catch(err) {}

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• Delivering Oracle DBaaS: Journey to Enterprise Cloud with Oracle Database 12c

  - by B R Clouse

  The release of Oracle Database 12c  is accompanied by extensive supporting collateral that details the new features and options of this major release.  But with so much to read and investigate, where to start?  If you don't have the time to pore through everything, then you may wish organize your reading in terms of the use case you're most interested in.  If your interest is Database as a Service in private database clouds then may I suggest that you start here: Accelerate the Journey to Enterprise Cloud with Oracle Database 12c Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-ascii- mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi- mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} This paper describes the phases of the journey to enterprise cloud, and enumerates the new features and options in Oracle Database 12c that support each phase.  Oracle Multitenant figures prominently, but it's not the only cloud-enabling topic: Oracle Database Quality of Service Management, Application Continuity, Automatic Data Optimization, Global Data Services and Active Data Guard Far Sync all deliver key benefits for delivering database as a service.  Further reading and research is suggested by the references included in the paper. Happy clouding!

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• How To Backup Of MySQL Database Using PhpMyAdmin

  - by Jyoti

  It is very important to do backup of your MySql database, you will probably realize it when it is too late. A lot of web applications use MySql for storing the content. This can be blogs, and a lot of other things. When you have all your content as html files on your web server it is very easy to keep them safe from crashes, you just have a copy of them on your own PC and then upload them again after the web server is restored after the crash. All the content in the MySql database must also be backed up. If you have spent a lot of time making the content and it is only stored in the Mysql server, you will feel very bad if it gets lost for ever. Backing it up once every month or so makes sure you never loose too much of your work in case of a server crash, and it will make you sleep better at night. It is easy and fast, so there is no reason for not doing it. Step 1: Log into phpMyAdmin on your server. Step2: You can select the database that you would like to backup from the drop-down menu called Database. Step 3: A new page will be loaded in phpMyAdmin showing the selected database. In order to proceed with the backup click on the Export tab. Step 4: The options that you should select apart from the default ones are Save as file which will save the file locally to your computer in an .sql format and Add DROP TABLE which will add the drop table functionality if the table already exists in the database backup as shown below. Step 5: Click on the Go button to start the export/backup procedure for your database. A download window will pop up prompting for the exact place where you would like to save the file on your local computer. It is possible that the download starts automatically. This depends on your browser’s settings.

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• Oracle Database 12c Technical Trainin

  - by mseika

  Audience Database Administrators, Solutions Architects, System Engineers, Technical Consultants, Implementation and support personnel, Technical Analysts, and Developers. What We Are Announcing During his opening keynote at Oracle OpenWorld 2012, Larry Ellison previewed Oracle Database 12c - the latest generation of the database market leader and Oracle flagship product. Oracle Database 12c introduces many groundbreaking features making it the database foundation of choice for the cloud. Many years of development effort have been focused on introducing innumerable new technological innovations centered on the cloud computing platform. This training session will focus on the specific needs of our Oracle partner community and developers, and provide insight into the many features and capabilities your customers will be looking to leverage in their own environments. Topics includes: Consolidation and Cloud Strategies Deep dive into the key Database 12c Options Migrating to Oracle Database 12c Webcast Details Speaker: Sean Stacey, Director of Platform Technology Solutions.Please note that you will need to join both the Audio and Web Conferences to attend. Please plan on joining 10 minutes before the scheduled time. Region: Date & Time Audio Conference Web Conference Calendar NAS, LAD, EMEA July 28am PT (US) Duration: 1 hour US/Canada: (866) 900-7470Click for local numberIf your country is not listed, dial +1 (706) 634-7953. Local charges may applyCONFERENCE ID: 98498078 Click here to joinPassword: Oracle123 Add this session to your calendar If you have any questions, please contact: Yvonne OungSenior Manager, Channel [email protected]

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• How the OS Makes the Database Scream

  - by rickramsey

  source Few things are as satisfying as a screaming burnout. When Oracle Database engineers team up with Solaris engineers, they do a lot of them. Here are a few of the reasons why. Article: How the OS Makes the Database Fast - Oracle Solaris For applications that rely on Oracle Database, a high-performance operating system translates into faster transactions, better scalability to support more users, and the ability to support larger capacity databases. When deployed in virtualized environments, multiple Oracle Database servers can be consolidated on the same physical server. Ginny Henningsen describes what Oracle Solaris does to make the Oracle database run faster. Interview: Why Is The OS Still Relevant? In a world of increasing virtualization and growing interest in cloud services, why is the OS still relevant? Michael Palmeter, senior director of Oracle Solaris, explains why it's not only relevant, but essential for data centers that care about performance. Interview: An Engineer's Perspective: Why the OS Is Still Relevant Sysadmins are handling hundreds or perhaps thousands of VM's. What is it about Solaris that makes it such a good platform for managing those VM's? Liane Praza, senior engineer in the Solaris core engineering group provides an engineer's perspective. Interview in the Lab: How to Get the Performance Promised by Oracle's T5 SPARC Chips If you want your applications to run on the new SPARC T5/M5 chips, how do you make sure they use all that new performance? Don Kretsch, Senior Director of Engineering, explains. Interview: Why Oracle Database Engineering Uses Oracle Solaris Studio The design priorities for Oracle Solaris Studio are performance, observability, and productivity. Why this is good for ISV's and developers, and why it's so important to the Oracle database engineering team. Taped in Oct 2012. - Rick Follow me on: Blog | Facebook | Twitter | YouTube | The Great Peruvian Novel

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• Oracle Database 11g Express Edition(XE)????~??????????????????????

  - by Yuichi Hayashi

  Oracle Database 11g (11.2.0.2)??????????????? Oracle Database 11g Express Edition(XE)?????????????Oracle Database????????(11.2.0.2)?????????????????????? v$version??11.2.0.2???????? ?????? Oracle Technology Network(OTN)????????????? http://www.oracle.com/technetwork/database/express-edition/downloads/index.html ???? XE?????????????????????? 1CPU????(???CPU???????????1CPU???????) 1???????1????????????????1DB???????????? ????????????11GByte?? ????????(RAM)?1GByte?? ????????????Windows(x86)???Linux(x86_64) Web???????????? Oracle 11g XE??????web??????????????????????? [??????????????] ??????????????????????????????????????????????Oracle Database?????????????????????????????????? [?????????????] ???????????SQL Developer????????SQL Developer???????????????????? ??????????? ?SQL Developer????~??????????????DB???SQL??? http://blogs.oracle.com/oracle4engineer/entry/sql_developersql Web?????????????? Oracle 11g XE????????Application Express???????????????????????????APEX????????????????APEX???????????????????????? APEX?????????????????????Oracle Application Express(APEX) - ??(??), ??, ??????????????? http://blogs.oracle.com/oracle4engineer/entry/cat_apex ?????? & ??????????? ????????????(DBA)??????????????????????·????????Oracle 11g XE??????????????????????????????????????????????????????&?????????????? [??????&?????????????] [???????????????RMAN(Recovery Manager)??????] ?????????????????????????Oracle Database??????????????????????Oracle 11g XE??????????????????????? ????Oracle???:Oracle Database 11g Express Edition(XE)??????????!

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• Webcast: Best Practices for Speeding Virtual Infrastructure Deployment with Oracle VM

  - by Honglin Su

  We announced Oracle VM Blade Cluster Reference Configuration last month, see the blog. The new Oracle VM blade cluster reference configuration can help reduce the time to deploy virtual infrastructure by up to 98 percent when compared to multi-vendor configurations. Customers and partners have shown lots of interests. Join Oracle's experts to learn the best practices for speeding virtual infrastructure deployment with Oracle VM, register the webcast (1/25/2011) here.   Virtualization has already been widely accepted as a means to increase IT flexibility and help IT services align better with changing business needs. The flexibility of a virtualized IT infrastructure enables new applications to be rapidly deployed, capacity to be easily scaled, and IT resources to be quickly redirected. The net result is that IT can bring greater value to the business, making virtualization an obvious win from a business perspective. However, building a virtualized infrastructure typically requires assembling and integrating multiple components (e.g. servers, storage, network, virtualization, and operating systems). This infrastructure must be deployed and tested before applications can even be installed. It can take weeks or months to plan, architect, configure, troubleshoot, and deploy a virtualized infrastructure. The process is not only time-consuming, but also error-prone, making it hard to achieve a timely and profitable return on investment.  Oracle is the only vendor that can offer a fully integrated virtualization infrastructure with all of the necessary hardware and software components. The Oracle VM blade cluster reference configuration is a single-vendor solution that addresses every layer of the virtualization stack with Oracle hardware and software components, see the figure below. It enables quick and easy deployment of the virtualized infrastructure using components that have been tested together and are all supported together by Oracle. To learn more about Oracle's virtualization offerings, visit http://oracle.com/virtualization.

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• www.foobar.com works but foobar.com results in a 'Server not found' error

  - by Homunculus Reticulli

  I have just setup a minimal (hopefully secure? - comments welcome) apache website using the following configuration file: <VirtualHost *:80> ServerName foobar.com ServerAlias www.foobar.com ServerAdmin [email protected] DocumentRoot /path/to/websites/foobar/web DirectoryIndex index.php # CustomLog with format nickname LogFormat "%h %l %u %t \"%r\" %>s %b" common CustomLog "|/usr/bin/cronolog /var/log/apache2/%Y%m.foobar.access.log" common LogLevel notice ErrorLog "|/usr/bin/cronolog /var/log/apache2/%Y%m.foobar.errors.log" <Directory /> AllowOverride None Order Deny,Allow Deny from all </Directory> <Directory /path/to/websites/> Options -Indexes FollowSymLinks MultiViews AllowOverride None Order allow,deny allow from all </Directory> </VirtualHost> I am able to access the website by using www.foobar.com, however when I type foobar.com, I get the error 'Server not found' - why is this? My second question concerns the security implications of the directive: <Directory /path/to/websites/> Options -Indexes FollowSymLinks MultiViews AllowOverride None Order allow,deny allow from all </Directory> in the configuration above. What exactly is it doing, and is it necessary?. From my (admitedly limited) understanding of Apache configuration files, this means that anyone will be able to access (write to?) the /path/to/websites/ folder. Is my understanding correct? - and if yes, how is this not a security risk?

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• How can I implement a database TableView like thing in C++?

  - by Industrial-antidepressant

  How can I implement a TableView like thing in C++? I want to emulating a tiny relation database like thing in C++. I have data tables, and I want to transform it somehow, so I need a TableView like class. I want filtering, sorting, freely add and remove items and transforming (ex. view as UPPERCASE and so on). The whole thing is inside a GUI application, so datatables and views are attached to a GUI (or HTML or something). So how can I identify an item in the view? How can I signal it when the table is changed? Is there some design pattern for this? Here is a simple table, and a simple data item: #include <string> #include <boost/multi_index_container.hpp> #include <boost/multi_index/member.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/random_access_index.hpp> using boost::multi_index_container; using namespace boost::multi_index; struct Data { Data() {} int id; std::string name; }; struct row{}; struct id{}; struct name{}; typedef boost::multi_index_container< Data, indexed_by< random_access<tag<row> >, ordered_unique<tag<id>, member<Data, int, &Data::id> >, ordered_unique<tag<name>, member<Data, std::string, &Data::name> > > > TDataTable; class DataTable { public: typedef Data item_type; typedef TDataTable::value_type value_type; typedef TDataTable::const_reference const_reference; typedef TDataTable::index<row>::type TRowIndex; typedef TDataTable::index<id>::type TIdIndex; typedef TDataTable::index<name>::type TNameIndex; typedef TRowIndex::iterator iterator; DataTable() : row_index(rule_table.get<row>()), id_index(rule_table.get<id>()), name_index(rule_table.get<name>()), row_index_writeable(rule_table.get<row>()) { } TDataTable::const_reference operator[](TDataTable::size_type n) const { return rule_table[n]; } std::pair<iterator,bool> push_back(const value_type& x) { return row_index_writeable.push_back(x); } iterator erase(iterator position) { return row_index_writeable.erase(position); } bool replace(iterator position,const value_type& x) { return row_index_writeable.replace(position, x); } template<typename InputIterator> void rearrange(InputIterator first) { return row_index_writeable.rearrange(first); } void print_table() const; unsigned size() const { return row_index.size(); } TDataTable rule_table; const TRowIndex& row_index; const TIdIndex& id_index; const TNameIndex& name_index; private: TRowIndex& row_index_writeable; }; class DataTableView { DataTableView(const DataTable& source_table) {} // How can I implement this? // I want filtering, sorting, signaling upper GUI layer, and sorting, and ... }; int main() { Data data1; data1.id = 1; data1.name = "name1"; Data data2; data2.id = 2; data2.name = "name2"; DataTable table; table.push_back(data1); DataTable::iterator it1 = table.row_index.iterator_to(table[0]); table.erase(it1); table.push_back(data1); Data new_data(table[0]); new_data.name = "new_name"; table.replace(table.row_index.iterator_to(table[0]), new_data); for (unsigned i = 0; i < table.size(); ++i) std::cout << table[i].name << std::endl; #if 0 // using scenarios: DataTableView table_view(table); table_view.fill_from_source(); // synchronization with source table_view.remove(data_item1); // remove item from view table_view.add(data_item2); // add item from source table table_view.filter(filterfunc); // filtering table_view.sort(sortfunc); // sorting // modifying from source_able, hot to signal the table_view? // FYI: Table view is atteched to a GUI item table.erase(data); table.replace(data); #endif return 0; }

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