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  • Should I partition my main table with 2 millions rows?

    - by domribaut
    Hi, I am a developer and would need some DBA-advices. We are starting to get performance problem with a MSSQL2005 database. The visible effects of the incidents is mainly CPU-hog on the server but operations reported that it was also draining resources from the SAN (not always). the main source of issues is for sure in some application but I am wondering if we should partition some of the main tables anyway in order to relax the I/O pressure. The base is about 60GB in one file. The main table (order) has 2.1 Million rows with a 215 colones (but none is huge). We have an integer as PK so it should be OK to define a partition function. Will we win something with partitioning? will partition indexes buy us something? Here are some more facts about the DB and the table database_name database_size unallocated space My_base 57173.06 MB 79.74 MB reserved data index_size unused 29 444 808 KB 26 577 320 KB 2 845 232 KB 22 256 KB name rows reserved data index_size unused Order 2 097 626 4 403 832 KB 2 756 064 KB 1 646 080 KB 1688 KB Thanks for any advice Dom

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  • Entity Framework and multi-tenancy database design

    - by Junto
    I am looking at multi-tenancy database schema design for an SaaS concept. It will be ASP.NET MVC - EF, but that isn't so important. Below you can see an example database schema (the Tenant being the Company). The CompanyId is replicated throughout the schema and the primary key has been placed on both the natural key, plus the tenant Id. Plugging this schema into the Entity Framework gives the following errors when I add the tables into the Entity Model file (Model1.edmx): The relationship 'FK_Order_Customer' uses the set of foreign keys '{CustomerId, CompanyId}' that are partially contained in the set of primary keys '{OrderId, CompanyId}' of the table 'Order'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The relationship 'FK_OrderLine_Customer' uses the set of foreign keys '{CustomerId, CompanyId}' that are partially contained in the set of primary keys '{OrderLineId, CompanyId}' of the table 'OrderLine'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The relationship 'FK_OrderLine_Order' uses the set of foreign keys '{OrderId, CompanyId}' that are partially contained in the set of primary keys '{OrderLineId, CompanyId}' of the table 'OrderLine'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The relationship 'FK_Order_Customer' uses the set of foreign keys '{CustomerId, CompanyId}' that are partially contained in the set of primary keys '{OrderId, CompanyId}' of the table 'Order'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The relationship 'FK_OrderLine_Customer' uses the set of foreign keys '{CustomerId, CompanyId}' that are partially contained in the set of primary keys '{OrderLineId, CompanyId}' of the table 'OrderLine'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The relationship 'FK_OrderLine_Order' uses the set of foreign keys '{OrderId, CompanyId}' that are partially contained in the set of primary keys '{OrderLineId, CompanyId}' of the table 'OrderLine'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The relationship 'FK_OrderLine_Product' uses the set of foreign keys '{ProductId, CompanyId}' that are partially contained in the set of primary keys '{OrderLineId, CompanyId}' of the table 'OrderLine'. The set of foreign keys must be fully contained in the set of primary keys, or fully not contained in the set of primary keys to be mapped to a model. The question is in two parts: Is my database design incorrect? Should I refrain from these compound primary keys? I'm questioning my sanity regarding the fundamental schema design (frazzled brain syndrome). Please feel free to suggest the 'idealized' schema. Alternatively, if the database design is correct, then is EF unable to match the keys because it perceives these foreign keys as a potential mis-configured 1:1 relationships (incorrectly)? In which case, is this an EF bug and how can I work around it?

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  • Pulling record from mySQL database only working for userid and not email

    - by user2908467
    This function works because I search by userid: private void showList_Click(object sender, EventArgs e) { int id = 0; for (int i = 0; i <= sqlClient.Count("UserList"); i++) { Dictionary<string, string> dik = sqlClient.Select("UserList", "userid = " + id); var lines = dik.Select(kv => kv.Key + ": " + kv.Value.ToString()); userList.AppendText(string.Join(Environment.NewLine, lines)); userList.AppendText(Environment.NewLine); userList.AppendText("--------------------------------------"); id++; } } This function does not work because I search by email: private void login_Click(object sender, EventArgs e) { string email = lemail.Text; Dictionary<string, string> dik = sqlClient.Select("UserList", "firstname = " + email); var lines = dik.Select(kv => kv.Key + ": " + kv.Value.ToString()); logged.AppendText(string.Join(Environment.NewLine, lines)); } This is the error message I receive when I click on the login button: 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 '@aol.com' at line 1 The email I searched for in the database was "[email protected]" without quotes. I'm lead to believe by the error message the @ sign is causing conflict as I know it is a special character but I am having a hard time figuring out what phrase to search for to help me. Also, here is the function that is being called: public Dictionary<string, string> Select(string table, string WHERE) { //This methods selects from the database, it retrieves data from it. //You must make a dictionary to use this since it both saves the column //and the value. i.e. "age" and "33" so you can easily search for values. //Example: SELECT * FROM names WHERE name='John Smith' // This example would retrieve all data about the entry with the name "John Smith" //Code = Dictionary<string, string> myDictionary = Select("names", "name='John Smith'"); //This code creates a dictionary and fills it with info from the database. string query = "SELECT * FROM " + table + " WHERE " + WHERE + ""; Dictionary<string, string> selectResult = new Dictionary<string, string>(); if (this.Open()) { MySqlCommand cmd = new MySqlCommand(query, conn); MySqlDataReader dataReader = cmd.ExecuteReader(); try { while (dataReader.Read()) { for (int i = 0; i < dataReader.FieldCount; i++) { selectResult.Add(dataReader.GetName(i).ToString(), dataReader.GetValue(i).ToString()); } } dataReader.Close(); } catch { } this.Close(); return selectResult; } else { return selectResult; } } My database table is called "UserList" The fields in order are as follows: userid, email, password, lastname, firstname Any help would be greatly appreciated. This site is amazing!

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  • Getting a Web Resource Url in non WebForms Applications

    - by Rick Strahl
    WebResources in ASP.NET are pretty useful feature. WebResources are resources that are embedded into a .NET assembly and can be loaded from the assembly via a special resource URL. WebForms includes a method on the ClientScriptManager (Page.ClientScript) and the ScriptManager object to retrieve URLs to these resources. For example you can do: ClientScript.GetWebResourceUrl(typeof(ControlResources), ControlResources.JQUERY_SCRIPT_RESOURCE); GetWebResourceUrl requires a type (which is used for the assembly lookup in which to find the resource) and the resource id to lookup. GetWebResourceUrl() then returns a nasty old long URL like this: WebResource.axd?d=-b6oWzgbpGb8uTaHDrCMv59VSmGhilZP5_T_B8anpGx7X-PmW_1eu1KoHDvox-XHqA1EEb-Tl2YAP3bBeebGN65tv-7-yAimtG4ZnoWH633pExpJor8Qp1aKbk-KQWSoNfRC7rQJHXVP4tC0reYzVw2&t=634533278261362212 While lately excessive resource usage has been frowned upon especially by MVC developers who tend to opt for content distributed as files, I still think that Web Resources have their place even in non-WebForms applications. Also if you have existing assemblies that include resources like scripts and common image links it sure would be nice to access them from non-WebForms pages like MVC views or even in plain old Razor Web Pages. Where's my Page object Dude? Unfortunately natively ASP.NET doesn't have a mechanism for retrieving WebResource Urls outside of the WebForms engine. It's a feature that's specifically baked into WebForms and that relies specifically on the Page HttpHandler implementation. Both Page.ClientScript (obviously) and ScriptManager rely on a hosting Page object in order to work and the various methods off these objects require control instances passed. The reason for this is that the script managers can inject scripts and links into Page content (think RegisterXXXX methods) and for that a Page instance is required. However, for many other methods - like GetWebResourceUrl() - that simply return resources or resource links the Page reference is really irrelevant. While there's a separate ClientScriptManager class, it's marked as sealed and doesn't have any public constructors so you can't create your own instance (without Reflection). Even if it did the internal constructor it does have requires a Page reference. No good… So, can we get access to a WebResourceUrl generically without running in a WebForms Page instance? We just have to create a Page instance ourselves and use it internally. There's nothing intrinsic about the use of the Page class in ClientScript, at least for retrieving resources and resource Urls so it's easy to create an instance of a Page for example in a static method. For our needs of retrieving ResourceUrls or even actually retrieving script resources we can use a canned, non-configured Page instance we create on our own. The following works just fine: public static string GetWebResourceUrl(Type type, string resource ) { Page page = new Page(); return page.ClientScript.GetWebResourceUrl(type, resource); } A slight optimization for this might be to cache the created Page instance. Page tends to be a pretty heavy object to create each time a URL is required so you might want to cache the instance: public class WebUtils { private static Page CachedPage { get { if (_CachedPage == null) _CachedPage = new Page(); return _CachedPage; } } private static Page _CachedPage; public static string GetWebResourceUrl(Type type, string resource) { return CachedPage.ClientScript.GetWebResourceUrl(type, resource); } } You can now use GetWebResourceUrl in a Razor page like this: <!DOCTYPE html> <html <head> <script src="@WebUtils.GetWebResourceUrl(typeof(ControlResources),ControlResources.JQUERY_SCRIPT_RESOURCE)"> </script> </head> <body> <div class="errordisplay"> <img src="@WebUtils.GetWebResourceUrl(typeof(ControlResources),ControlResources.WARNING_ICON_RESOURCE)" /> This is only a Test! </div> </body> </html> And voila - there you have WebResources served from a non-Page based application. WebResources may be a on the way out, but legacy apps have them embedded and for some situations, like fallback scripts and some common image resources I still like to use them. Being able to use them from non-WebForms applications should have been built into the core ASP.NETplatform IMHO, but seeing that it's not this workaround is easy enough to implement.© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  MVC   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Using json as database with EF, how can I link EF and the json file during DbContext initialization?

    - by blacai
    For a personal testing-project I am considering to create a SPA with the following technologies: ASP.NET MVC + EF + WebAPI + AngularJS. The project will make use of small amount of data, so I was thinking I could use just a .json file as storage. But I am not sure about how to proceed with the link between EF and the json file in the initialization of the DbContext. I found a stackoverflow related question: http://stackoverflow.com/questions/13899342/can-we-use-json-as-a-database I know the basics of edit files and store data inside. What I tried is to get the data from the json file in the initilizer method and create the objects one by one. This is more a doubt about how this works if I save/update an object in the dbcontext, do I need to go through all the elements and add/update it manually? Is it better to rewrite the complete file? According to this http://stackoverflow.com/questions/7895335/append-data-to-a-json-file-with-php it is not a good practice to use json/XML for data wich will be manipulated. Anyone has experience with anything similar? Is this a really bad idea and I should use another kind of data-storage?

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  • In an online questionnaire, what is a best way to design a database for keeping track of users all attempts?

    - by user1990525
    We have a web app where users can take online exams. Exam admin will create a questionnaire. A questionnaire can have many Questions. Each question is a multiple choice question (MCQ). Lets say an admin creates a questionnaire with 10 questions. Users attempt those questions. Now, unlike real exams users can attempt single questionnaire multiple times. And we have to keep track of his all attempts. e.g. User_id Questionnaire_id question_id answer attempt_date attempt_no 1 1 1 a 1 June 2013 1 1 1 2 b 1 June 2013 1 1 1 1 c 2 June 2013 2 1 1 2 d 2 June 2013 2 Now it can also happen that after user has attempted same questionnare twice, admin can delete a question from same questionnaire, but users attempt history should still have reference to that so that user can see his that question in his attempt history in spite of admin deleting that question. If user now attempts this changed questionnaire he should see only 1 question. User_id Questionnaire_id question_id answer attempt_date attempt_no 1 1 1 a 3 June 2013 3 Also, after this user modified some part of question, users attempt history should show question before modification while any new attempt should show modified question. How do we manage this at the database level? My first gut feeling was that, For deletes, do not do physical delete, just make a question inactive so that history can still keep track of users attempt. For modifications, create versions for questions and each new attempt refres to latest version of each question and history keeping reference to version of question at attempt time.

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  • Would this data requirement suit a Document -Oriented database?

    - by codecowboy
    I have a requirement to allow users to fill in journal/diary entries per day. I want to provide a handful of known journal templates with x columns to fill in. An example might be a thought diary; a user has to record a thought in one column, describe the situation, rate how they felt etc. The other requirement is that a user should be able to create their own diary templates. They might have a need for a 10 column diary entry per day and might need to rate some aspect out of 50 instead of 10. In an RDBMS, I can see this getting quite complicated. I could have individual tables for my known templates as the fields will be fixed. But for custom diary templates I imagine I would would need a table storing custom_field_types (the diary columns), a table storing entries referencing their field types (custom_entries) and then a third custom_diary table which would store rows matching custom_entries to diaries. Leaving performance / scaling aside, would it be any simpler or make more sense to use a document oriented database like MongoDB to store this data? This is for a web application which might later need an API for mobile devices.

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  • Database development/admin - What exactly should I be trying to learn? [closed]

    - by Sauron
    I've been a bit weary about approaching learning databases. I've dabbled into them before, and "DATA" in itself appeals to me a lot. Maintaining/searching/moving, everything about it in the abstract sense I love. (This isn't a career question, this is a learning question.) But as RDBMS's begin to be easier to maintain, and with tools that "anyone" can use to manage data I feared for the database admin jobs. (Yet I see jobs for SQL everywhere!). I know "No-SQL" was a big deal but it kinda has its niche. But that leaves me here... unsure of really "what" to study. What tools should I have in my tool belt? I'm sure RDBMS's will be around in both use and maintaining legacy code. But what else? Obviously data will always be around, but is this a secure field or a dying one? And what should I be concentrating on?

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  • SQL – Quick Start with Admin Sections of NuoDB – Manage NuoDB Database

    - by Pinal Dave
    In the yesterday’s blog post we have seen that it is extremely easy to install the NuoDB database on your local machine. Now that the application is properly set up, let us explore NuoDB a bit more and get you familiar with the how it works and what the important areas of the NuoDB are that you should learn. As we have already installed NuoDB, now we will quickly start with two of the important areas in NuoDB: 1) Admin and 2) Explorer. In this blog post I will explore how the Admin Section of the NuoDB Console works.  In the next blog post we will learn how the Explorer Section works. Let us go to the NuoDB Console by typing the following URL in your browser: http://localhost:8080/ It will bring you to the following screen: On this screen you can see a big Start QuickStart button. Click on the button and it will bring you to following screen. On this screen you will find very important information about Domain and Database Settings. It is our habit that we do not read what is written on the screen and keep on clicking on continue without reading. While we are familiar with most wizards, we can often miss the very important message on the screen. Please note the information of Domain Settings and Database Settings from the following screen before clicking on Create Database. Domain Settings User: quickstart Password: quickstart Database Settings User: dba Password: goalie Database: test Schema: HOCKEY Once you click on the Create Database button it will immediately start creating sample database. First, it will start a Storage Manager and right after that it will start a Transaction Engine. Once the engine is up, it will Create a Schema and Sample Data. On the success of the creating the sample database it will show the following screen. Now is the time where we can explore the NuoDB Admin or NuoDB Explorer. If you click on Admin, it will first show following login screen. Enter for the username “domain” and for the password “bird”. Alternatively you can enter “quickstart”  twice for username and password.  It works as too. Once you enter into the Admin Section, on the left side you can see information about NuoDB and Admin Console and on the right side you can see the domain overview area. From this Administrative section you can do any of the following tasks: Create a view of the entire domain Add and remove databases Start and stop NuoDB Transaction Engines and Storage Managers Monitor transaction across all the NuoDB databases On the right side of the Admin Section we can see various information about a particular NuoDB domain. You can quickly view various alerts, find out information about the number of host machines that are provisioned for the domain, and see the number of databases and processes that are running in the domain. If you click on the “1 host” link you will be able to see various processes, CPU usage and other information. In the Processes Section you can see that there are two different types of processes. The first process (where you can see the floppy drive icon) represents a running Storage Manager process and the second process a running Transaction Engine process. You can click on the links for the Storage Manager and Transaction Engine to see further statistical details right down to the last byte of the data. There are various charts available for analysis as well. I think the product is quite mature and the user can add different monitor charts to the Admin section. Additionally, the Admin section is the place where you can create and manage new databases. I hope today’s tutorial gives you enough confidence that you can try out NuoDB and checkout various administrative activities with the database. I am personally impressed with their dashboard related to various counters. For more information about how the NuoDB architecture works and what a Storage Manager or Transaction Engine does, check out this short video with NuoDB CTO Seth Proctor:  In the next blog post, we will try out the Explorer section of NuoDB, which allows us to run SQL queries and write SQL code.  Meanwhile, I strongly suggest you download and install NuoDB and get yourself familiar with the product. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: NuoDB

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  • SQL SERVER – master Database Log File Grew Too Big

    - by pinaldave
    Couple of the days ago, I received following email and I find this email very interesting and I feel like sharing with all of you. Note: Please read the whole email before providing your suggestions. “Hi Pinal, If you can share these details on your blog, it will help many. We understand the value of the master database and we take its regular back up (everyday midnight). Yesterday we noticed that our master database log file has grown very large. This is very first time that we have encountered such an issue. The master database is in simple recovery mode; so we assumed that it will never grow big; however, we now have a big log file. We ran the following command USE [master] GO DBCC SHRINKFILE (N'mastlog' , 0, TRUNCATEONLY) GO We know this command will break the chains of LSN but as per our understanding; it should not matter as we are in simple recovery model.     After running this, the log file becomes very small. Just to be cautious, we took full backup of the master database right away. We totally understand that this is not the normal practice; so if you are going to tell us the same, we are aware of it. However, here is the question for you? What operation in master database would have caused our log file to grow too large? Thanks, [name and company name removed as per request]“ Here was my response to them: “Hi [name removed], It is great that you are aware of all the right steps and method. Taking full backup when you are not sure is always a good practice. Regarding your question what could have caused your master database log to grow larger, let me try to guess what could have happened. Do you have any user table in the master database? If yes, this is not recommended and also NOT a good practice. If have user tables in master database and you are doing any long operation (may be lots of insert, update, delete or rebuilding them), then it can cause this situation. You have made me curious about your scenario; do revert back. Kind Regards, Pinal” Within few minutes I received reply: “That was it Pinal. We had one of the maintenance task log tables created in the master table, which had many long transactions during the night. We moved it to newly created database named ‘maintenance’, and we will keep you updated.” I was very glad to receive the email. I do not suggest that any user table should be created in the master database. It should be left alone from user objects. Now here is the question for you – can you think of any other reason for master log file growth? Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Backup and Restore, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Migrating SQL Server Compact Edition (SQL CE) database to SQL Server using Web Matrix

    - by Harish Ranganathan
    One of the things that is keeping us busy is the Web Camps we are delivering across 5 cities.  If you are a reader of this blog, and also attended one of these web camps, there is a good chance that you have seen me since I was there in all the places, so far.  The topics that we cover include Visual Studio 2010 SP1, SQL CE, ASP.NET MVC & HTML5.  Whenever I talk about SQL CE, the immediate response is that, people are wow that Microsoft has shipped a FREE compact edition database, which is an embedded database that can be x-copy deployed.  If you think, well didn’t Microsoft ship SQL Express which is FREE?  The difference is that, SQL Express runs as a service in the machine (if you open SQL Configuration Manager, you can notice that SQL Express is running as a service along with your SQL Server Engine (if you have installed ).  This makes it that, even if you are willing to use SQL Express when you deploy your application, it needs to be installed on the production machine (hosting provider) and it needs to run as a service.  Many hosters don’t allow such services to run on their space. SQL CE comes as a x-Copy deploy-able database with just a few DLLs required to run it on the machine and they don’t even need to be installed in GAC on the production machine.  In fact, if you have Visual Studio 2010 SP1 installed, you can use the “Add Deployable Dependencies” option in Project-Properties and it would detect that SQL CE is something you would probably want to add as a deploy-able dependency for your project.  With that, it bundles the required DLLs as a part of the “_bin_deployableAssemblies” folder.  So your project can be x-Copy deployed and just works fine. However, SQL CE has the limit of 4GB storage space.  Real world applications often require more than just 4GB of data storage and it often turns out that people would like to use SQL CE for development/ramp up stages but would like to migrate to full fledged SQL Server after a while.  So, its only natural that the question arises “How do I move my SQL CE database to SQL Server”  And honestly, it doesn’t come across as a straight forward support.  I was talking to Ambrish Mishra (PM in SQL CE Team, Hyderabad) since I got this question in almost all the places where we talked about SQL CE.   He was kind enough to demonstrate how this can be accomplished using Web Matrix.  Open Web Matrix (Web Matrix can be installed for free from www.microsoft.com/web) and click on “Site from Template” Click on the “Bakery” template (since by default it uses a SQL CE database and has all the required sample data) and click “Ok”. In the project, you can navigate to the Database tab and will be able to find that the Bakery site uses a SQL CE database “bakery.sdf” Select the “bakery.sdf” and you will be able to see the “Migrate” button on the top right Once you click on the “Migrate” button, you will notice that the popup wizard opens up and by default is configured for SQL Express.  You can edit the same to point to your local SQL Server instance, or a remote server. Upon filling in the Server Name, Username and Password, when you click “Ok”, couple of things happen.  1. The database is migrated to SQL Server (local or remote – subject to permissions on remote server).   You can open up SQL Server Management Studio and connect to the server to verify that the “bakery” database exists under “Databases” node. 2. You can also notice that in Web Matrix, when you navigate to the “Files” tab and open up the web.config file, connection string now points to the SQL Server instance (yes, the Migrate button was smart enough to make this change too ) And there it is, your SQL Server Compact Edition database, now migrated to SQL Server!! In a future post, I would explain the steps involved when using Visual Studio. Cheers !!!

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  • Normalisation and 'Anima notitia copia' (Soul of the Database)

    - by Phil Factor
    (A Guest Editorial for Simple-Talk) The other day, I was staring  at the sys.syslanguages  table in SQL Server with slightly-raised eyebrows . I’d just been reading Chris Date’s  interesting book ‘SQL and Relational Theory’. He’d made the point that you’re not necessarily doing relational database operations by using a SQL Database product.  The same general point was recently made by Dino Esposito about ASP.NET MVC.  The use of ASP.NET MVC doesn’t guarantee you a good application design: It merely makes it possible to test it. The way I’d describe the sentiment in both cases is ‘you can hit someone over the head with a frying-pan but you can’t call it cooking’. SQL enables you to create relational databases. However,  even if it smells bad, it is no crime to do hideously un-relational things with a SQL Database just so long as it’s necessary and you can tell the difference; not only that but also only if you’re aware of the risks and implications. Naturally, I’ve never knowingly created a database that Codd would have frowned at, but around the edges are interfaces and data feeds I’ve written  that have caused hissy fits amongst the Normalisation fundamentalists. Part of the problem for those who agonise about such things  is the misinterpretation of Atomicity.  An atomic value is one for which, in the strange virtual universe you are creating in your database, you don’t have any interest in any of its component parts.  If you aren’t interested in the electrons, neutrinos,  muons,  or  taus, then  an atom is ..er.. atomic. In the same way, if you are passed a JSON string or XML, and required to store it in a database, then all you need to do is to ask yourself, in your role as Anima notitia copia (Soul of the database) ‘have I any interest in the contents of this item of information?’.  If the answer is ‘No!’, or ‘nequequam! Then it is an atomic value, however complex it may be.  After all, you would never have the urge to store the pixels of images individually, under the misguided idea that these are the atomic values would you?  I would, of course,  ask the ‘Anima notitia copia’ rather than the application developers, since there may be more than one application, and the applications developers may be designing the application in the absence of full domain knowledge, (‘or by the seat of the pants’ as the technical term used to be). If, on the other hand, the answer is ‘sure, and we want to index the XML column’, then we may be in for some heavy XML-shredding sessions to get to store the ‘atomic’ values and ensure future harmony as the application develops. I went back to looking at the sys.syslanguages table. It has a months column with the months in a delimited list January,February,March,April,May,June,July,August,September,October,November,December This is an ordered list. Wicked? I seem to remember that this value, like shortmonths and days, is treated as a ‘thing’. It is merely passed off to an external  C++ routine in order to format a date in a particular language, and never accessed directly within the database. As far as the database is concerned, it is an atomic value.  There is more to normalisation than meets the eye.

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  • Blueprints for Oracle NoSQL Database

    - by dan.mcclary
    I think that some of the most interesting analytic problems are graph problems.  I'm always interested in new ways to store and access graphs.  As such, I really like the work being done by Tinkerpop to create Open Source Software to make property graphs more accessible over a wide variety of datastores.  Since key-value stores like Oracle NoSQL Database are well-suited to storing property graphs, I decided to extend the Blueprints API to work with it.  Below I'll discuss some of the implementation details, but you can check out the finished product here: http://github.com/dwmclary/blueprints-oracle-nosqldb.  What's in a Property Graph?  In the most general sense, a graph is just a collection of vertices and edges.  Vertices and edges can have properties: weights, names, or any number of other traits.  In an undirected graph, edges connect vertices without direction.  A directed graph specifies that all edges have a head and a tail --- a direction.  A multi-graph allows multiple edges to connect two vertices.  A "property graph" encompasses all of these traits. Key-Value Stores for Property Graphs Key-Value stores like Oracle NoSQL Database tend to be ideal for implementing property graphs.  First, if any vertex or edge can have any number of traits, we can treat it as a hash map.  For example: Vertex["name"] = "Mary" Vertex["age"] = 28 Vertex["ID"] = 12345  and so on.  This is a natural key-value relationship: the key "name" maps to the value "Mary."  Moreover if we maintain two hash maps, one for vertex objects and one for edge objects, we've essentially captured the graph.  As such, any scalable key-value store is fertile ground for planting graphs. Oracle NoSQL Database as a Scalable Graph Database While Oracle NoSQL Database offers useful features like tunable consistency, what lends it to storing property graphs is the storage guarantees around its key structure.  Keys in Oracle NoSQL Database are divided into two parts: a major key and a minor key.  The storage guarantee is simple.  Major keys will be distributed across storage nodes, which could encompass a large number of servers.  However, all minor keys which are children of a given major key are guaranteed to be stored on the same storage node.  For example, the vertices: /Personnel/Vertex/1  and /Personnel/Vertex/2 May be stored on different servers, but /Personnel/Vertex/1-/name and  /Personnel/Vertex/1-/age will always be on the same server.  This means that we can structure our graph database such that retrieving all the properties for a vertex or edge requires I/O from only a single storage node.  Moreover, Oracle NoSQL Database provides a storeIterator which allows us to store a huge number of vertices and edges in a scalable fashion.  By storing the vertices and edges as major keys, we guarantee that they are distributed evenly across all storage nodes.  At the same time we can use a partial major key to iterate over all the vertices or edges (e.g. we search over /Personnel/Vertex to iterate over all vertices). Fork It! The Blueprints API and Oracle NoSQL Database present a great way to get started using a scalable key-value database to store and access graph data.  However, a graph store isn't useful without a good graph to work on.  I encourage you to fork or pull the repository, store some data, and try using Gremlin or any other language to explore.

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  • Populate Android Database From CSV file?

    - by MoMo
    Is it possible to take a csv file stored in the res/raw resource directory and use it to populate a table in the sqlite3 database? My thought was that, if there was a way to do a bulk import for the entire file into the table then that would be cleaner and faster than iterating over each line in the file and executing individual insert statements... I've found that there is a sqlite import command that allows this: http://stackoverflow.com/questions/1045910/how-can-i-import-load-a-sql-or-csv-file-into-sqlite ...but I'm having trouble applying those statements in my Android application. My first thought was to try something like the following...but no luck: db.execSQL("CREATE TABLE " + TABLE_NAME + "(id INTEGER PRIMARY KEY, name TEXT)"); db.execSQL(".mode csv"); db.execSQL(".import res/raw/MyFile.csv " + TABLE_NAME); Is this possible? Should I be trying a different approach to populate my database? Thanks for you answers!

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  • Erlang: 2 database on 2 webserver ??

    - by xRobot
    I have created a blogging system with php+postgresql. Now I want to add a web chat ( in REAL TIME for Million of users simultaneously ) where every message is saved in database. I am thinking to use Erlang+Mnesia on a different webserver for this issue. Message's table will be like this: message_id, user_id, message, date user_id should be related with users table in Postgresql database in another webserver. How can I do that without lose performance ? If you have any other creative solutions tell me please ;).

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  • Delphi connection to OpenEdge Progress-4GL Database

    - by Cesar Marrero
    Folks: Has anyone had success connecting to a Progress-4GL database with Delphi?   I've been unable to establish any connection with the ODBC driver provided by the vendor (Progress OpenEdge 10.1C Driver). I've entered (what I believe are) the right parameters, but keep on getting an error whenever I test the connection: "[DataDirect][ODBC Progress OpenEdge Wire Protocol driver] Socket closed." Background: I've been tasked to re-design a 13-year-old application, but the original programmer did not provide any supporting documents, passwords, configuration setup, etc. (I'm on my own)!   To make things worse, online help and useful documentation about Progress is scarce (I had never heard about this database until now). I want to examine the existing data, maybe create an ERD to familiarize myself with the schema, but I can't even access the data outside of the OpenEdge code. Any help is appreciated!

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  • Database entries existence depends on time / boolean value of a field changed automatically

    - by lisak
    Hey, I have this situation here. An auction system listing orders that are "active" (their deadline didn't occur yet) There is a lot of orders so it is better to have a field "active" instead of listing them based on time queries I'm not a database expert, just a user. What is the best way to implement this scenario ? Do I have to manually check the "deadLine" field and change "active" status every once in a while ? Is Mysql able to change the field automatically ? How demanding are queries of type "select orders where "deadline" has passed " Do I need to use TIMESTAMP (long data type of number of milisecond since UTC epoch time or DATETIME for the queries to the database to be more efficient ? Finally I have to move old order entries to a different backup table .

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  • Store and retrieve images from file system instead of database

    - by Karsten
    Hi I need a place to store images. My first thought was to use the database, but many seems to recommend using the filesystem. This seems to fit my case, but how do I implement it? The filenames need to be unique, how to do that. Should I use a guid? How to retrieve the files, should I go directly to the database using the filename, make a aspx page and passing either filename or primary key as a querystring and then read the file. What about client side caching, is that enabled when using a page like image.aspx?id=123 ? How do I delete the files, when the associated record is deleted? I guess there are many other things that I still haven't thought about. Links, samples and guidelines are very welcome!

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  • Database design - alternatives for Entity Attribute Value (EAV)

    - by Bob
    Hi, see http://stackoverflow.com/questions/695752/product-table-many-kinds-of-product-each-product-has-many-parameters for similar topic. My question: i want to design a database, that will be used for a production facility of different types of products where each product has its own (number of) parameters. because i want the serial numbers to be in one tabel for overview purposes i have a problem with these different paraeters . One solution could be EAV, but it has its downsides, certainly because we have +- 5 products with every product +- 20.000 serial numbers (records). it looks a bit overkill to me... I just don't know how one could design a database so that you have an attribute in a mastertable that says: 'hey, you could find details of this record in THAT detail-table". 'in a way that you qould easely query the results) currenty i am using Visual Basic & Acces 2007. but i'm going to Visual Basic & MySQL. thanks for your help. Bob

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  • Make list from two database items

    - by unnamet
    I want to make a list from some data that I have in my database. The first two sets of data in my database are first name and last name. I want my list to show both first and last name instead of now where it only shows the first name. How do I do that? My code looks like this: private void fillData() { Cursor contactCursor = mDbHelper.fetchAllReminders(); startManagingCursor(contactCursor); String[] from = new String[]{DbAdapter.KEY_FIRST}; int[] to = new int[]{R.id.contactlist}; SimpleCursorAdapter contacts = new SimpleCursorAdapter(this, R.layout.list, contactCursor, from, to); setListAdapter(contacts); }

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  • Unable to connect to mysql database using tomcat6 on ubuntu

    - by Rakesh
    I am able to deploy the application on my local system.... connecting to the same remote database... however when I deploy the same war file on the ubuntu server I get the following exception javax.servlet.ServletException: Could not connect to wikipedia database... org.wikipedia.miner.service.WikipediaMinerServlet.init(WikipediaMinerServlet.java:81) sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) java.lang.reflect.Method.invoke(Method.java:616) org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:244) java.security.AccessController.doPrivileged(Native Method) javax.security.auth.Subject.doAsPrivileged(Subject.java:537) org.apache.catalina.security.SecurityUtil.execute(SecurityUtil.java:276) org.apache.catalina.security.SecurityUtil.doAsPrivilege(SecurityUtil.java:162) org.apache.catalina.security.SecurityUtil.doAsPrivilege(SecurityUtil.java:115) org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286) org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845) org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583) org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) java.lang.Thread.run(Thread.java:636) I have even placed the mysql connector jar under tomcat6 lib direcotry.... Please help

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  • Removing non-alphanumeric characters in an Access Field.

    - by Jacques Tardie
    I need to remove hyphens from a string in a large number of access fields. What's the best way to go about doing this? Currently, the entries are follow this general format: 2010-54-1 2010-56-1 etc. I'm trying to run append queries off of this field, but I'm always getting validation errors causing the query to fail. I think the cause of this failure is the hypens in the entries, which is why I need to remove them. I've googled, and I see that there are a number of formatting guides using vbscript, but I'm not sure how I can integrate vb into Access. It's new to me :) Thanks in advance, Jacques

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  • Designing Database

    - by user548192
    Hello All, I need to design database with frontend as HTML. This is my first attempt to do this. What I need is, - User can input a word from HTML page, click submit I will query the word to get a URL from database and user sees that webpage(pointed by URL). Just enter word, submit and get the webpage displayed. People suggested using JSP/Access. I am new to everything. Can you please point out what exactly I need to do? Thanks a ton.

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  • Setting the database connection when using a TransactionScope

    - by eych
    Does the database connection have to be set inside a TransactionScope? Or can I set it in the ctor and then have instance methods create up a TransactionScope? EDIT: e.g. Public Sub New() Dim conn = new SqlConnection(...connection string) Public Sub SomeClassMethod() using ts as new TransactionScope //conn has already been initialized //so, here you can set commands, ExecuteDataSet, etc. vs Public Sub New() //nothing here Public Sub SomeClassMethod() using ts as new TransactionScope conn = new SqlConnection(...connection string) set commands, ExecuteDataSet, etc. the question is do you need to create the connection to the database after you've created a TransactionScope or can it be done before?

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