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  • I need an approach to the problem of preventing inserting duplicate records into the database

    - by Maurice
    Apologies is this question is asked on the incorrect "stack" A webservice that I call returns a list of data. The data from the webservice is updated periodically, so a call to the webservice done in one hour could return the same data as a call done in an hour. Also, the data is returned based on a start and end date. We have multiple users that can run the webservice search, and duplicate data is most likely to be returned (especially for historical data). However I don't want to insert this duplicate data in the database. I've created a db table in which the data is stored (most important columns are) Id int autoincrement PK Date date not null --The date to which the data set belongs. LastUpdate date not null --The date the data set was last updated. UserName varchar(50) --The name of the user doing the search. I use sql server 2008 express with c# 4.0 and visual studio 2010. Entity Framework is used as the ORM. If stored procedures could be avoided in the proposed solution, then that will be a plus. Another way of looking interpreting what I'm asking a solution for is as follows: I have a million unique records in my table. A user does a new search. The search results from the user contains around 300k of the data that is already in the db. An efficient solution to finding an inserting only the unique records is needed.

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  • What relational database system should I learn? [closed]

    - by acidzombie24
    At the moment i know sqlite (my favorite), mysql (its ok, i get annoyed) and i do not want to learn ms/t sql (it only allows one nullable row if the column is unique). I am thinking about learning a new database system. My requirements for it is Must allow multiple connections at once (read and write) All or data i choose must be ACID compliant Performance should be good. I have a 17gb table in one project. It should perform well on read and transactional writes. With mysql it took hours to restore it and there were no foreign keys on that specific table. It only finished in a workday because i found a suggestion to adjust a setting which i think was key-buffer. And it still took hours Unique columns that allow more then one row to be null. I shouldn't have to say it but dammit MS. Allows one to make ongoing backups. Something like 'binary logs'. Some relatively small amounts of data i can grab and apply it to my local db to have it in sync with the one on the server. Table joins. I rather not write a bunch of queries to simulate a join What I would like but is not required Foreign keys. This may be a requirement later Open sourced Fair tool support. So i can measure queries, easily backup/restore, etc .NET and C (or C++) interface. (I seen one that uses raw tcp with JSON which was okish) Good subquery support. Once i was working with an older version of mysql (i believe <5.1 but it could have been 5.1) and i had to write many queries to do one query because it couldn't do subqueries. Or maybe it couldnt do it efficiently and died bc of memory limitations with a huge dataset. What db system should i learn?

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  • Looking to create website that can have custom GUI and database per user

    - by riley3131
    I have developed an MS Access database for a company to track data in regards to production of a certain commodity. It has many many tables, forms, reports, etc. These were all done as the user requested, and resemble the users previously used system, mostly printed worksheets and excel workbooks. This has created a central location for all information and has allowed the company to compare data in a new way. I am now looking to do this for other companies, but would like to switch it to a web application. Here is my question. What is the best way to create unique solutions for individual companies that can have around 100 users each? I would love to create one site that would serve all parties, but that would ruin the customizable nature of what I am developing. I love the ability to create reports, excel sheets, pdf, graphs, etc with access, but am tired of relying on my customers software, servers, etc. I have some experience with WAMP, but I am far better at VBA. I was okay at PHP, and was getting a grasp on JavaScript a few years back. I am also trying to decide whether to go with WAMP or LAMP, if web is the best choice. Also, should I try set up one site for all users that after log-in goes to company specific pages, or individual sites for each company? Should I host or use a service?

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  • Choosing the Database Solution for Large Data Application

    - by GµårÐïåñ
    I have been tasked to write an application that will be a combination of document and inventory management in VB.net which will be used to store document images in TIFF, PDF, XPS, TXT, DOC, PPT and so on as binary data that can be retrieved for viewing, printing, and possible OCR to be searchable as well along with meta data such as sender, recipient, type of document, date, source, etc. So the table would probably be something like: DOC_NAME, DOC_DATE, NOTES, ... DOC_BINARY (where the actual document will be put inside) What my concern is finding a database solution that will not become unstable due to size restrictions, records limitations and performance. Some of the options are MS_SQL, SQL Express, SQLite, mySQL, and Access. Now I can pretty much eliminate Access right off the bat as it is just too limiting and not scalable. I can further eliminate SQL Express because of the 2 GB limit and again scalability. So that leaves me with MS_SQL, SQLite and mySQL (although if anyone has other options they think would be good as well, please feel free to share them, by no means am I set on these only). So this brings me to what you guys think is the best option for what I have described. The goal is that the data is all in one place (a single file) that will make backup and portability easier. For small volume usage, pretty much any solution will hold for a while, but my goal is to think ahead and make sure its able to withstand heavy large volume usage as well. Another consideration is also the interoperability with .NET and stability of such code to avoid errors and memory leaks. Your feedback would be greatly appreciated.

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  • Applying Test Driven Development to a tightly coupled architecture

    - by Chris D
    Hi all, I've recently been studying TDD, attended a conference and have dabbled in few tests and already I'm 100% sold, I absolutely love it TDD. As a result I've raised this with my seniors and they are prepared to give it a chance, so they have tasked me with coming up with a way to implement TDD in the development of our enterprise product. The problem is our system has evolved since the days of VB6 to .NET and implements alot of legacy technology and some far from best practice development techniques i.e. alot of business logic in the ASP.NET code behind and client script. The largest problem however is how our classes are tightly coupled with database access; properties, methods, constructors - usually has some database access in some form or another. We use an in-house data access code generator tool that creates sqlDataAdapters that gives us all the database access we could ever want, which helps us develop extremely quickly, however, classes in our business layer are very tightly coupled to this data layer - we aren't even close to implementing some form of repository design. This and the issues above have created me all sorts of problems. I have tried to develop some unit tests for some existing classes I've already written but the tests take ALOT longer to run since db access is required, not to mention since we use the MS Enterprise Caching framework I am forced to fake a httpcontext for my tests to run successfully which isn't practical. Also, I can't see how to use TDD to drive the design of any new classes I write since they have to be soo tightly coupled to the database ... help! Because of the architecture of the system it appears I can't implement TDD without some real hack which in my eyes just defeats the aim of TDD and the huge benefits that come with. Does anyone have any suggestions how I could implement TDD with the constraints I'm bound too? or do I need to push the repository design pattern down my seniors throats and tell them we either change our architecture/development methodology or forget about TDD altogether? :) Thanks

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  • ???????/???Web????????????!??????????????

    - by Yusuke.Yamamoto
    ????? ??:2010/11/04 ??:??????/?? ???????????????????·????????????????????????????????????????????????????????Web?????????????????????????????????????????????????????DB?? Oracle TimesTen In-Memory Database ???????????????????????????? ????????????????????????Oracle In-Memory Database Cache ?????Oracle TimesTen IMDB / Oracle IMDB Cache 11g ?????????? ????????? ????????????????? http://otndnld.oracle.co.jp/ondemand/otn-seminar/movie/TT11041100.wmv http://www.oracle.com/technology/global/jp/ondemand/otn-seminar/pdf/TimesTen_OrD_20101104_print.pdf

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  • Good embedded database solution (like SQLite) for .Net

    - by vfilby
    I am looking for file based storage solutions that I can use with a .Net project. THey need to have a sql-like interface for storing and retrieving data. They need to have relatively little overhead and must not require any additional components installed by the end user. I am hopping for a .dll that I can reference and use. Cool points awarded if it is closely tied to an ORM. My current favourite is SQLite, are there any better ones out there that I should know about? I have a (health?) bias against access because I feel it is overcomplicated for what I need, I am open to being convinced otherwise though. PS: "No, there is nothing better than SQLite" is a perfectly good answer.

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  • how to generate dbml file from Sybase database?

    - by 5YrsLaterDBA
    I think we may have trouble with our existing project. For some reasons we have to switch from SQL Server to Sybase SQL Anywhere 11. now we trying to find a way continue use our existing LINQ code. We wish we can still use L2S? If cannot, we wish we can use L2E, then we have to change to ADO. how to generate dbml file from Sybase Anywhere 11? after that can we use sqlmetal to generate .cs files?

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  • Using a DataSet instead of custom business entities in soa and n-tier architecture

    - by kathy
    I’m working on a large and a high volume transactional enterprise application which has been designed using n-tire application architecture .And it was developed in the .NET platform utilizing C#,VB.NEt, Framework 3.5, ObjectDataSources, DataSet, WCF, asp.net update panel, JavaScript ,JSON, 3rd Party tools. The application is supposed to accomplish a really scalable / easily maintained / robust application / integrations, and to make sure that my services are created using a format that can be understood by other systems. The problem is, this application is about 70% complete but now I was wondering if the following would cause us future issues, I’m using a DataSet and a DataTable to (get /set) the data (form /to) the stored procedure in the database using the ObjectDataSources and was wondering if this would prevent my application from achieving the above goals. Actually, I am not anti-OO. I write lots of classes for different purposes, but I didn’t use the entity objects(custom business entities) instead of the previous way because I have a large database that may contain 50 tables and I was just afraid to create entities for each table and then in the future if I need to change the schema of the database, it might cause a huge affect on the application ?

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  • Non-relational database modeling tool?

    - by Angel Escobedo
    Hey guys, please recommend some tools you have used succesfully on DW, DataMart, BI an non-relational modeling. Example for automatic creation of snow-flake Schemas, dimensions and facts tables. Wich tools makes you sense familiarity with the diagrams and surrogates keys and it will have the option for export or connect to SQL Server 2008. Thanks

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  • Is it easy to switch from relational to non-relational databases with Rails?

    - by Tam
    Good day, I have been using Rails/Mysql for the past while but I have been hearing about Cassandra, MongoDB, CouchDB and other document-store DB/Non-relational databases. I'm planning to explore them later as they might be better alternative for scalability. I'm planning to start an application soon. Will it make a different with Rails design if I move from relational to non-relational database? I know Rails migrations are database-agnostic but wasn't sure if moving to non-relational will make difference with design or not.

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  • database design to speed up hibernate querying of large dataset

    - by paddydub
    I currently have the below tables representing a bus network mapped in hibernate, accessed from a Spring MVC based bus route planner I'm trying to make my route planner application perform faster, I load all the above tables into Lists to perform the route planner logic. I would appreciate if anyone has any ideas of how to speed my performace Or any suggestions of another method to approach this problem of handling a large set of data Coordinate Connections Table (INT,INT,INT)( Containing 50,000 Coordinate Connections) ID, FROMCOORDID, TOCOORDID 1 1 2 2 1 17 3 1 63 4 1 64 5 1 65 6 1 95 Coordinate Table (INT,DECIMAL, DECIMAL) (Containing 4700 Coordinates) ID , LAT, LNG 0 59.352669 -7.264341 1 59.352669 -7.264341 2 59.350012 -7.260653 3 59.337585 -7.189798 4 59.339221 -7.193582 5 59.341408 -7.205888 Bus Stop Table (INT, INT, INT)(Containing 15000 Stops) StopID RouteID COORDINATEID 1000100001 100 17 1000100002 100 18 1000100003 100 19 1000100004 100 20 1000100005 100 21 1000100006 100 22 1000100007 100 23 This is how long it takes to load all the data from each table: stop.findAll = 148ms, stops.size: 15670 Hibernate: select coordinate0_.COORDINATEID as COORDINA1_2_, coordinate0_.LAT as LAT2_, coordinate0_.LNG as LNG2_ from COORDINATES coordinate0_ coord.findAll = 51ms , coordinates.size: 4704 Hibernate: select coordconne0_.COORDCONNECTIONID as COORDCON1_3_, coordconne0_.DISTANCE as DISTANCE3_, coordconne0_.FROMCOORDID as FROMCOOR3_3_, coordconne0_.TOCOORDID as TOCOORDID3_ from COORDCONNECTIONS coordconne0_ coordinateConnectionDao.findAll = 238ms ; coordConnectioninates.size:48132 Hibernate Annotations @Entity @Table(name = "STOPS") public class Stop implements Serializable { @Id @GeneratedValue @Column(name = "COORDINATEID") private Integer CoordinateID; @Column(name = "LAT") private double latitude; @Column(name = "LNG") private double longitude; } @Table(name = "COORDINATES") public class Coordinate { @Id @GeneratedValue @Column(name = "COORDINATEID") private Integer CoordinateID; @Column(name = "LAT") private double latitude; @Column(name = "LNG") private double longitude; } @Entity @Table(name = "COORDCONNECTIONS") public class CoordConnection { @Id @GeneratedValue @Column(name = "COORDCONNECTIONID") private Integer CoordinateID; /** * From Coordinate_id value */ @Column(name = "FROMCOORDID", nullable = false) private int fromCoordID; /** * To Coordinate_id value */ @Column(name = "TOCOORDID", nullable = false) private int toCoordID; //private Coordinate toCoordID; }

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  • Database Design Primay Key, ID vs String

    - by LnDCobra
    Hi, I am currently planning to develop a music streaming application. And i am wondering what would be better as a primary key in my tables on the server. An ID int or a Unique String. Methods 1: Songs Table: SongID(int), Title(string), Artist*(string), Length(int), Album*(string) Genre Table Genre(string), Name(string) SongGenre: SongID*(int), Genre*(string) Method 2 Songs Table: SongID(int), Title(string), ArtistID*(int), Length(int), AlbumID*(int) Genre Table GenreID(int), Name(string) SongGenre: SongID*(int), GenreID*(int) Key: Bold = Primary Key, Field* = Foreign Key I'm currently designing using method 2 as I believe it will speed up lookup performance and use less space as an int takes a lot less space then a string. Is there any reason this isn't a good idea? Is there anything I should be aware of?

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  • Need help to create database schema for wholesale online tee store

    - by techiepark
    Hi, I'm currently working on wholesale online t-shirt shop. I have done this for fixed quantity and price, and its working fine. Now i need to do this for variable quantity and price. Here is the reference link, like what i have to do. Basic tables i have created are - CREATE TABLE attribute ( attribute_id int(11) NOT NULL auto_increment, name varchar(100) NOT NULL, PRIMARY KEY (attribute_id) ); CREATE TABLE attribute_value ( attribute_value_id int(11) NOT NULL auto_increment, attribute_id int(11) NOT NULL, value varchar(100) NOT NULL, PRIMARY KEY (attribute_value_id), KEY idx_attribute_value_attribute_id (attribute_id) ); CREATE TABLE product ( product_id int(11) NOT NULL auto_increment, name varchar(100) NOT NULL, description varchar(1000) NOT NULL, price decimal(10,2) NOT NULL, image varchar(150) default NULL, thumbnail varchar(150) default NULL, PRIMARY KEY (product_id), FULLTEXT KEY idx_ft_product_name_description (name,description) ); CREATE TABLE product_attribute ( product_id int(11) NOT NULL, attribute_value_id int(11) NOT NULL, PRIMARY KEY (product_id,attribute_value_id) ); I'm not getting how to store the price based on variable quantity. Please help me to create product and its related tables. my requirement is same as above reference link.

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  • Buddy List: Relational Database Table Design

    - by huntaub
    So, the modern concept of the buddy list: Let's say we have a table called Person. Now, that Person needs to have many buddies (of which each buddy is also in the person class). The most obvious way to construct a relationship would be through a join table. i.e. buddyID person1_id person2_id 0 1 2 1 3 6 But, when a user wants to see their buddy list, the program would have to check the column 'person1_id' and 'person2_id' to find all of their buddies. Is this the appropriate way to implement this kind of table, or would it be better to add the record twice.. i.e. buddyID person1_id person2_id 0 1 2 1 2 1 So that only one column has to be searched. Thanks in advance.

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  • Database solutions for storing/searching EXIF data

    - by webdestroya
    I have thousands of photos on my site (each with a numeric PhotoID) and I have EXIF data (photos can have different EXIF tags as well). I want to be able to store the data effectively and search it. Some photos have more EXIF data than others, some have the same, so on.. Basically, I want to be able to query say 'Select all photos that have a GPS location' or 'All photos with a specific camera' I can't use MySQL (tried it, it doesn't work). I thought about Cassandra, but I don't think it lets me query on fields. I looked at SimpleDB, but I would rather: not pay for the system, and I want to be able to run more advanced queries on the data. Also, I use PHP and Linux, so it would be awesome if it could interface nicely to PHP. Any ideas?

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  • Best way to auto-restore db on an houlry basis

    - by aron
    Hello, I have a demo site where anyone can login and test a management interface. Every hour I would like to flush all the data in the SQL 2008 Database and restore it from the original. Rae Gate sql has some awesome tools for this, however they are beyond my budget right now. Could I simply make a backup copy of the database's data file, then have a c# console app that deletes it and copies over the original. Then I can have a windows schedule task to run the .exe every hour. It's simple and free... would this work? I'm using SQL Server 2008 R2 Web edition I understand that red gate is technically better because I can set it to analyze the db and only update the records that were altered, and the approach I have above is like a "sledge hammer".

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  • How do I normalise this database design?

    - by Ian Roke
    I am creating a rowing reporting and statistics system for a client where I have a structure at the moment similar to the following: ----------------------------------------------------------------------------- | ID | Team | Coaches | Rowers | Event | Position | Time | ----------------------------------------------------------------------------- | 18 | TeamName | CoachName1 | RowerName1 | EventName | 1 | 01:32:34 | | | | CoachName2 | RowerName2 | | | | | | | | RowerName3 | | | | | | | | RowerName4 | | | | ----------------------------------------------------------------------------- This is an example row of data but I would like to expand this out to a Rowers table and Coaches table and so on but I don't know how best to then link that back to the Entries table which is what this is. Has anybody got any words of wisdom they could share with me? Update A Team can have any number of Coaches and Rowers, a Rower can be in many Teams (Team A, B, C etc) and a Team can have many Coaches.

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  • Database model for saving random boolean expressions

    - by zarko.susnjar
    I have expressions like this: (cat OR cats OR kitten OR kitty) AND (dog OR dogs) NOT (pigeon OR firefly) Anyone having idea how to make tables to save those? Before I got request for usage of brackets, I limited usage of operators to avoid ambiguous situations. So only ANDs and NOTs or only ORs and saved those in this manner: operators id | name 1 | AND 2 | OR 3 | NOT keywords id | keyword 1 | cat 2 | dog 3 | firefly expressions id | operator | keywordId 1 | 0 | 1 1 | 1 | 2 1 | 3 | 3 which was: cat AND dog NOT firefly But now, I'm really puzzled...

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  • Rating System Database Structure

    - by Harsha M V
    I have two entity groups. Restaurants and Users. Restaurants can be rated (1-5) by users. And rating fromeach user should be retrievable. Resturant(id, name, ..... , total_number_of_votes, total_voting_points ) User (id, name ...... ) Rating (id, restaurant_id, user_id, rating_value) Do i need to store the avg value so that it need not be calculated every time ? which table is the best place to store avg_rating, total_no_of_votes, total_voting_points ?

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  • Database that consumes less disk space

    - by Hugo Palma
    I'm looking at solutions to store a massive quantity of information consuming the less possible disk space. The information structure is very simple and the queries will also be very simple. I've looked at solutions like Apache Cassandra and relations databases but couldn't find a comparison where disk usage is mentioned. Any ideas on this would be great.

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  • Need to work out database structure

    - by jim smith
    Hi, Just need a little kickstart with this. I have Mysql/PHP, and I have 5,000 products. I have 30 companies I need to store some data for those 30 companies for each product as follows: a) prices b) stock qty I also need to store data historically on a daily basis. So the table... It makes sense that the records will be the products because there's 5000, and if I put the companies as the columns, I can store the prices, but what about the stock quantities? I could create two columns for each compoany, one for prices, one for qty. Then make the tablename the date for that day...so theer would be a new table for every day with 5000 products in it? is this the correct way? Some idea on how I'll be retreiving data the top 5 lowest prices (and the company) by product for a certain date the price and stock changes in the past 7 days by product

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  • Database Modelling - Conceptually different entities but with near identical fields

    - by Andrew Shepherd
    Suppose you have two sets of conceptual entities: MarketPriceDataSet which has multiple ForwardPriceEntries PoolPriceForecastDataSet which has multiple PoolPriceForecastEntry Both different child objects have near identical fields: ForwardPriceEntry has MarketPriceDataSetId (foreign key to parent table) StartDate EndDate SimulationItemId ForwardPrice PoolPriceForecastEntry has PoolPriceForecastDataSetId (foreign key to parent table) StartDate EndDate SimulationItemId ForecastPoolPrice If I modelled them as separate tables, the only difference would be the foreign key, and the name of the price field. There has been a debate as to whether the two near identical tables should be merged into one. Options I've thought of to model this is: Just keep them as two independent, separate tables Have both sets in the one table with an additional "type" field, and a parent_id equalling a foreign key to either parent table. This would sacrifice referential integrity checks. Have both sets in the one table with an additional "type" field, and create a complicated sequence of joining tables to maintain referential integrity. What do you think I should do, and why?

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