Search Results

Search found 952 results on 39 pages for 'relational'.

Page 28/39 | < Previous Page | 24 25 26 27 28 29 30 31 32 33 34 35  | Next Page >

• Is adding indexes to a SQL Server ever a bad idea?

  - by Aerik

  We have a mid-size SQL Server based application that has no indexes defined. Not even on the the identity columns. I suggested to our moderately expensive application consultant that perhaps we might get better performance (particularly as our database grows) by creating some indexes on appropriate fields, and he said: "Indexes will significantly impact other areas of the application and customers should not create them under any circumstances." Anybody ever heard of anything like this? Are there ever circumstances where one should not create any indexes? I can see nothing special about this app - it's got int identity columns, then lots of string columns, bunch of relational tables but nothing special or weird that I can see. Thanks!

  Read the article

• Scaffolding Web Services in Grails

  - by Dan

  I need to implement a web app, but instead of using relational database I need to use different SOAP Web Services as a back-end. An important part of application only calls web services and displays the result. Since Web Services are clearly defined in form of Operation: In parameters and Return Type it seems to me that basic GUI could be easily constructed just like in the case of scaffolding based on Domain Entities. For example in case of SearchProducts web service operation I need to enter search parameters as input, so the search page can be constructed. Operation will return a list of products, so I need a page that will display this list in some kind of table. Is there already some library in grails that let you achieve this. If not, how would you go about creating one?

  Read the article

• Cloned Cached item has memory issues

  - by ioWint

  Hi there, we are having values stored in Cache-Enterprise library Caching Block. The accessors of the cached item, which is a List, modify the values. We didnt want the Cached Items to get affected. Hence first we returned a new List(IEnumerator of the CachedItem) This made sure accessors adding and removing items had little effect on the original Cached item. But we found, all the instances of the List we returned to accessors were ALIVE! Object relational Graph showed a relationship between this list and the EnterpriseLibrary.CacheItem. So we changed the return to be a newly cloned List. For this we used a LINQ say (from item in Data select new DataClass(item) ).ToList() even when you do as above, the ORG shows there is a relationship between this list and the CacheItem. Cant we do anything to create a CLONE of the List item which is present in the Enterprise library cache, which DOESNT have ANY relationship with CACHE?!

  Read the article

• Core Data vs SQLite 3

  - by Jason Medeiros

  I am already quite familiar with relational databases and have used SQLite (and other databases) in the past. However, Core Data has a certain allure, so I am considering spending some time to learn it for use in my next application. Is there much benefit to using Core Data over SQLite, or vice versa? What are the pros/cons of each? I find it hard to justify the cost of learning Core Data when Apple doesn't use it for many of its flagship applications like Mail.app or iPhoto.app - instead opting for SQLite databases. SQLite is also used extensively on the iPhone. Can those familiar with using both comment on their experience? Perhaps, as with most things, the question is deeper than just using one over the other?

  Read the article

• Essential skills of a Data Scientist

  - by harshsinghal

  I would like to know more about the relevant skills in the arsenal of a Data Scientist, and with new technologies coming in every day, how one picks and chooses the essentials. A few ideas germane to this discussion: Knowing SQL and the use of a DB such as MySQL, PostgreSQL was great till the advent of NoSql and non-relational databases. MongoDB, CouchDB etc. are becoming popular to work with web-scale data. Knowing a stats tool like R is enough for analysis, but to create applications one may need to add Java, Python, and such others to the list. Data now comes in the form of text, urls, multi-media to name a few, and there are different paradigms associated with their manipulation. What about cluster computing, parallel computing, the cloud, Amazon EC2, Hadoop ? OLS Regression now has Artificial Neural Networks, Random Forests and other relatively exotic machine learning/data mining algos. for company Thoughts?

  Read the article

• Is there a declarative language for data definitions?

  - by Jekke

  Reading about WPF and thinking about my application's data store at the same time led me to wonder if there are any languages or tools that allow you to define relational data in a declarative way? A shallow Google search suggests no such thing exists. Yet it seems so obviously useful. The kind of tool I have in mind would declaratively describe (at least) entities, relationships and views is a platform-agnostic way that would act as an abstraction layer between data-driven applications and their datastores. Does any such tool exist?

  Read the article

• Are there any small scale, durable document/object databases?

  - by Joe Doyle

  I have a few .Net projects that would benefit from using a document/object database opposed to a relational one. I think that db4o would be a good choice, but we're not sure how much the cost is. I'd love to use MongoDB but it's design isn't for small scale, single server applications. Are there other options out there that I just haven't run across for small scale applications? EDIT: So is this a space that doesn't have a good solution, yet? Are there no small scale & durable document databases? Would my best choice be to use MongoDB and set the --syncdelay option set to 1?

  Read the article

• Conditional Join - join 1 tables 2 ways

  - by Jon H

  I have a set of (not very well normalised or relational) tables named PLAN, GROUP, PRODUCT CLIENT Most have linkage i.e. PLAN - CLIENT on clno GROUP to PRODUCT on PRODCD However, the linkage between PLAN and GROUP is tricky. A plan has 2 field of interest GRPNO and PRODCD. What I want to do is if GRPNO != 0 then join GROUP on GRPNO. However if GRPNO = 0 then I want to join GROUP on PRODCD. The frustrating thing is that the fileds I want to return in my queries are the same across the board I just need to be able to vary the join, or join the same table twice. The best I can come up with is 2 queries and merge them using datasets, or possibly using a union. Is there a nifty way to do this in one select? I should point out I am access Foxpro over ODBC to do this. Thank you!

  Read the article

• Is there a production ready web application framework in Python?

  - by peperg

  I heard lots of good opinions about Python language. They say it's mature, expressive etc... Are there any production-ready web application frameworks in Python. By "production ready" I mean : supports objective-relational mapping with caching and declarative desciption (like JPA, Hibernate etc..) controls oriented user interface support - no HTML templates but something like JSF (RichFaces, Icefaces) or GWT, Vaadin, ZK component decomposition and dependency injection (like EJB or Spring) unit and integration testing good IDE support clustering, modularity etc (like Terracota, OSGi etc..) there are successful applications written in it by companies like IBM, Oracle etc (I mean real business applications not Twitter) could have commercial support Is it possible at all in Python world ? Or only choices are : use Python and write everything from the bottom (too expensice) stick to JEE buy .NET stack

  Read the article

• NoSql Crash Course/Tutorial

  - by Chris Thompson

  Hi all, I've seen NoSQL pop up quite a bit on SO and I have a solid understanding of why you would use it (from here, Wikipedia, etc). This could be due to the lack of concrete and uniform definition of what it is (more of a paradigm than concrete implementation), but I'm struggling to wrap my head around how I would go about designing a system that would use it or how I would implement it in my system. I'm really stuck in a relational-db mindset thinking of things in terms of tables and joins... At any rate, does anybody know of a crash course/tutorial on a system that would use it (kind of a "hello world" for a NoSQL-based system) or a tutorial that takes an existing "Hello World" app based on SQL and converts it to NoSQL (not necessarily in code, but just a high-level explanation). I see this having one solid answer, but if you guys feel like it should be community wiki, I'll be happy to change it. Thanks! Chris

  Read the article

• Extracting Demographic and Contact Information from unstructured text files

  - by jn29098

  I am looking to extract specific items out of a large pool of unstructured documents. These documents could be 1-5 pages of text formatted in various ways by the user, but in most cases would contain at least: Name Address (physical) Email Address Phone number website URL I'm looking for a semantic parser that can attempt to extract these elements from the documents so that I can load that information into a relational database and work with these records as contacts. Other services I've looked for, while valuable for other purposes, do not address this specific need. Alchemy API Open Calais Saplo Any thoughts, suggestions or leads?

  Read the article

• 'e-Commerce' scalable database model

  - by Ruben Trancoso

  I would like to understand database scalability so I've just heard a talk about Habits of Highly Scalable Web Applications http://techportal.ibuildings.com/2010/03/02/habits-of-highly-scalable-web-applications/ On it, the presenter mainly talk about relational database scalability. I also have read something about MapReduce and Column oriented tables, big tables, hypertable etc... trying to understand which are the most up to date methods to scale web application data. But the second group, to me, is being hard to understand where it fits. It serves as transactional, reliable data store? or not, its just for large access and processing and to handle fine graned operations we will ever need to rely on RDBMSs? Could someone give a comprehensive landscape for those new technologies and how to use it?

  Read the article

• What are good hosting companies for PHP 5.3 Mysql / CouchDb / MongoDB Dev ( Lithium / CakePHP Framew

  - by Abba Bryant

  I am looking for a quality reliable host for some lithium development. I don't mind a shared platform as long as I have some ssh access. I require php 5.3.x, Mysql 5.x, and the usual imageMagick etc. Non-relational DB support up front would be nice but if they let me set one up myself I would be okay with doing it. I don't need a lot in the way of control panel tools. Good ones are appreciated but bad ones I would prefer not to even deal with. I don't anticipate needing much in the way of email but mail support would be nice to have. Cost isn't a big issue. I don't want to pay an arm and a leg but don't mind paying for what I need. Good support and decent uptime would be nice but I don't need an SLO or anything.

  Read the article

• What database works well with 200+GB of data?

  - by taw

  I've been using mysql (with innodb; on Amazon rds) because it's sort of universal default, but it's been ridiculously under-performing, and tweaking it only delays the inevitable. The data is mostly relatively short (<1kB of bytes each) blobs information about 100Ms of urls. There is (or should be, mysql cannot seem to handle it) very high amount of insert / update / retrieve but few complex queries - not that complex queries wouldn't be useful, but because mysql is so slow that it's far faster to get the data out, process it locally, and cache the results somewhere. I can keep tweaking mysql and throwing more hardware at it, but it seems increasingly futile. So what are the options? SQL/relational model/etc. optional - anything will do as long as it's fast, networked, and language-independent.

  Read the article

• Hierarchical Data in MySQL is fast to retrieve?

  - by ajsie

  i've got a list of all countries - states - cities (- subcities/villages etc) in a XML file and to retrieve for example a state's all cities it's really quick with XML (using xml parser). i wonder, if i put all this information in mysql, is retrieving a state's all cities as fast as with XML? cause XML is designed to store hierarchical data while relational databases like mysql are not. the list contains like 500 000 entities. so i wonder if its as fast as XML using either of: Adjacency list model Nested Set model And which one should i use? Cause (theoretically) there could be unlimited levels under a state. And which is fastest for this huge dataset? Thanks!

  Read the article

• MySQL dual license behavior

  - by jromero

  Hi SO, I'm running a commercial(closed source) Web App development for the first time. Initially I considered MySQL the most feasible option for a DB, until I get quite confused about its dual license behavior. If I want a commercial application do I still can use the GPL version of MySQL or I must get a license? The same question in a different way: If I use MySQL's GPL version does that force me to license the whole app under GPL? Either case I would go with PostgreSQL, I just want to make really really sure about this. Even in SO I've seen related("duplicates") questions but never a clear answer... All other tools I'm gonna use to code the project are licensed under BSD or MIT. Just in case, the role of MySQL in the project is merely as relational DB to store persistent data and query it. I'd really appreciate if someone can clarify this for me. Regards, thanks in advanced.

  Read the article

• Hierarchical Data in MySQL is as fast as XML to retrieve?

  - by ajsie

  i've got a list of all countries - states - cities (- subcities/villages etc) in a XML file and to retrieve for example a state's all cities it's really quick with XML (using xml parser). i wonder, if i put all this information in mysql, is retrieving a state's all cities as fast as with XML? cause XML is designed to store hierarchical data while relational databases like mysql are not. the list contains like 500 000 entities. so i wonder if its as fast as XML using either of: Adjacency list model Nested Set model And which one should i use? Cause (theoretically) there could be unlimited levels under a state (i heard that adjacency isn't good for unlimited child-levels). And which is fastest for this huge dataset? Thanks!

  Read the article

• Dealing w/ Sqlite Join results in a cursor

  - by Bill

  I have a one-many relationship in my local Sqlite db. Pretty basic stuff. When I do my left outer join I get back results that look like this: the resulting cursor has multiple rows that look like this: A1.id | A1.column1 | A1.column2 | B1.a_id_fk | B1.column1 | B1.column2 A1.id | A1.column1 | A1.column2 | B2.a_id_fk | B2.column1 | B2.column2 and so on... Is there a standard practice or method of dealing with results like this ? Clearly there is only A1, but it has many B-n relationships. I am coming close to using multiple queries instead of the "relational db way". Hopefully I am just not aware of the better way to do things. I intend to expose this query via a content provider and I would hate for all of the consumers to have to write the same aggregation logic.

  Read the article

• Should I use Perl or PHP or something else for this project?

  - by Clinton

  I'm about to embark on a project that will need to: Process XML Heavy text parsing of non-xml documents Insertion of data from xml and non-xml documents into a relational DB. Present processed data to user from db using webpages. The website will be subject to short periods of very heavy loads to pages (300+ visitors a minute for several minutes), but most of the time will be idle (a dozen or so visitors a minute). The ability to cache or scale to load will be very nice. I have a very strong background in Java and web services, but I do not want to use Java for this project as I'd like to diversify my skill set. Which language would you recommend and what are some pros and cons that you might recognize from your own experiences?

  Read the article

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

  - by jkff

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

  Read the article

• What format do I use to store a relatively small amount of user data

  - by wcm

  I am writing a small program for our local high school (pro bono). The program has an interface allows the user to enter school holidays. This is a simple stand alone Windows app. What format should I use to store the data? A big relational data is obviously overkill. My initial plan was to store the data in an XML file. Co-workers have been suggesting that I use JSON files, Access Databases, SQL Lite, and SQL Server Express. There was even a suggestion of old school INI files.

  Read the article

• Java: JPA classes, refactoring from Date to DateTime

  - by bguiz

  With a table created using this SQL Create Table X ( ID varchar(4) Not Null, XDATE date ); and an entity class defined like so @Entity @Table(name = "X") public class X implements Serializable { @Id @Basic(optional = false) @Column(name = "ID", nullable = false, length = 4) private String id; @Column(name = "XDATE") @Temporal(TemporalType.DATE) private Date xDate; //java.util.Date ... } With the above, I can use JPA to achieve object relational mapping. However, the xDate attribute can only store dates, e.g. dd/MM/yyyy. How do I refactor the above to store a full date object using just one field, i.e. dd/MM/yyyy HH24:mm?

  Read the article

• Strategy in storing ad-hoc numbers/constants?

  - by Jiho Han

  I have a need to store a number of ad-hoc figures and constants for calculation. These numbers change periodically but they are different type of values. One might be a balance, a money amount, another might be an interest rate, and yet another might be a ratio of some kind. These numbers are then used in a calculation that involve other more structured figures. I'm not certain what the best way to store these in a relational DB is - that's the choice of storage for the app. One way, I've done before, is to create a very generic table that stores the values as text. I might store the data type along with it but the consumer knows what type it is so, in situations I didn't even need to store the data type. This kind of works fine but I am not very fond of the solution. Should I break down each of the numbers into specific categories and create tables that way? For example, create Rates table, and Balances table, etc.?

  Read the article

• What's a better choice for SQL-backed number crunching - Ruby 1.9, Python 2, Python 3, or PHP 5.3?

  - by Ivan

  Crterias of 'better': fast im math and simple (little of fields, many records) db transactions, convenient to develop/read/extend, flexible, connectible. The task is to use a common web development scripting language to process and calculate long time series and multidimensional surfaces (mostly selectint/inserting sets of floats and dong maths with rhem). The choice is Ruby 1.9, Python 2, Python 3, PHP 5.3, Perl 5.12, JavaScript (node.js). All the data is to be stored in a relational database (due to its heavily multidimensional nature), all the communication with outer world is to be done by means of web services.

  Read the article

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

  - by Saif Bechan

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

  Read the article

< Previous Page | 24 25 26 27 28 29 30 31 32 33 34 35  | Next Page >