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  • Seeking free ODBC database optimization tool for non-experts

    - by mawg
    I'm a database n00b and am reading as many books as I can. I have been given responsibility for an ODBC tool where the databases were designed by a hardware engineer with some VB experience - which made him a s/w guru in the small firm at that time. Things are running slowly and I suspect that the db could have been designed better. I hope to learn enough to use Explain/Describe, etc maybe add some indices, but, in the meantime, is there any free for commercial use tool which can examine an ODBC database and suggest improvements. I'm just talking about db schema here, but maybe I should also be looking at optimizing Selects with Joins? Is there a tool for that? ODBC compliant.

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  • Application Code Redesign to reduce no. of Database Hits from Performance Perspective

    - by Rachel
    Scenario I want to parse a large CSV file and inserts data into the database, csv file has approximately 100K rows of data. Currently I am using fgetcsv to parse through the file row by row and insert data into Database and so right now I am hitting database for each line of data present in csv file so currently database hit count is 100K which is not good from performance point of view. Current Code: public function initiateInserts() { //Open Large CSV File(min 100K rows) for parsing. $this->fin = fopen($file,'r') or die('Cannot open file'); //Parsing Large CSV file to get data and initiate insertion into schema. while (($data=fgetcsv($this->fin,5000,";"))!==FALSE) { $query = "INSERT INTO dt_table (id, code, connectid, connectcode) VALUES (:id, :code, :connectid, :connectcode)"; $stmt = $this->prepare($query); // Then, for each line : bind the parameters $stmt->bindValue(':id', $data[0], PDO::PARAM_INT); $stmt->bindValue(':code', $data[1], PDO::PARAM_INT); $stmt->bindValue(':connectid', $data[2], PDO::PARAM_INT); $stmt->bindValue(':connectcode', $data[3], PDO::PARAM_INT); // Execute the statement $stmt->execute(); $this->checkForErrors($stmt); } } I am looking for a way wherein instead of hitting Database for every row of data, I can prepare the query and than hit it once and populate Database with the inserts. Any Suggestions !!! Note: This is the exact sample code that I am using but CSV file has more no. of field and not only id, code, connectid and connectcode but I wanted to make sure that I am able to explain the logic and so have used this sample code here. Thanks !!!

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  • Command Query Separation validating for retries

    - by Neil Barnwell
    So I'm comfortable with the basic concept of CQS, where you might have a command that writes to one database, and that updates the query database that you read from. However, consider the scenario where you are entering data, and want to prevent duplicates. Using new employee data entry an employee register as an example, working through a pile of application forms to key in the new employees' details: Take top sheet. Key in employee name and unique payroll number to UI. Submit. Put paper in "completed pile". Repeat. How would you now prevent the user from keying in the same payroll number again, say for instance if they get distracted and can't remember whether they've keyed one in already and the "message" hasn't got all the way back to the query db for the user to search?

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  • How to evade writing a lot of repetitive code when mapping?

    - by JPCF
    I have a data access layer (DAL) using Entity Framework, and I want to use Automapper to communicate with upper layers. I will have to map data transfer objects (DTOs) to entities as the first operation on every method, process my inputs, then proceed to map from entities to DTOs. What would you do to skip writing this code? As an example, see this: //This is a common method in my DAL public CarDTO getCarByOwnerAndCreditStatus(OwnerDTO ownerDto, CreditDto creditDto) { //I want to automatize this code on all methods similar to this Mapper.CreateMap<OwnerDTO,Owner>(); Mapper.CreateMap<CreditDTO,Credit>(); Owner owner = Mapper.map(ownerDto); Owner credit = Mapper.map(creditDto) //... Some code processing the mapped DTOs //I want to automatize this code on all methods similar to this Mapper.CreateMap<Car,CarDTO>(); Car car = Mapper.map(ownedCar); return car; }

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  • What strategies are efficient to handle concurrent reads on heterogeneous multi-core architectures?

    - by fabrizioM
    I am tackling the challenge of using both the capabilities of a 8 core machine and a high-end GPU (Tesla 10). I have one big input file, one thread for each core, and one for the the GPU handling. The Gpu thread, to be efficient, needs a big number of lines from the input, while the Cpu thread needs only one line to proceed (storing multiple lines in a temp buffer was slower). The file doesn't need to be read sequentially. I am using boost. My strategy is to have a mutex on the input stream and each thread locks - unlocks it. This is not optimal because the gpu thread should have a higher precedence when locking the mutex, being the fastest and the most demanding one. I can come up with different solutions but before rush into implementation I would like to have some guidelines. What approach do you use / recommend ?

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  • Would this constructor be acceptable practice?

    - by Robb
    Let's assume I have a c++ class that have properly implemented a copy constructor and an overloaded = operator. By properly implemented I mean they are working and perform a deep copy: Class1::Class1(const Class1 &class1) { // Perform copy } Class1& Class1::operator=(const Class1 *class1) { // perform copy return *this; } Now lets say I have this constructor as well: Class1::Class1(Class1 *class1) { *this = *class1; } My question is would the above constructor be acceptable practice? This is code that i've inherited and maintaining.

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  • Help with MySQL database structure - user notification system

    - by Simon
    Hi, I'd like to send global notifications to my users (1000+ users) and allow them to close the notification box once they have read the message. Basically I may send one notification per week globally ie/ each user get the same message and they are not personal in nature. What is the best way to achieve this? Create 2 tables: **tb_messages** message_id massage_title message_content **tb_read_messages** user_id message_id is-read That way i can just show each user the current notifications that are not read? select * from tb_read_messages WHERE user_id = $user_id AND is-read = no OR is there a more efficient way? Thanks!!!

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  • Best Practice for CouchDB Document Versioning

    - by Groundwater
    Following my question here I am exmploring ideas for a generic approach to document versioning in CouchDB. While I imagine there may be no canonical approach, I had the following idea and am looking for feedback. I would like to maintain readable document ids as much as possible, so a document existing at /document1 would contain a pointer document to all existing versions on the system. The actual revision documents would be at something like /document1/308ef032a3801a where 308ef032a3801a is some random number or hash. Example The pointer document { "_id" : "document1", "versions" : [ "document1/308ef032a3801a" ] } The version document { "_id" : "document1/308ef032a3801a", ... actual content }

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  • How to handle expired items?

    - by Mark
    My site allows users to post things on the site with an expiry date. Once the item has expired, it will no longer be displayed in the listings. Posts can also be closed, canceled, or completed. I think it would be be nicest just to be able to check for one attribute or status ("is active") rather than having to check for [is not expired, is not completed, is not closed, is not canceled]. Handling the rest of those is easy because I can just have one "status" field which is essentially an enum, but AFAIK, it's impossible to set the status to "expired" as soon as that time occurs. How do people typically handle this?

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  • Implementing a live voting system

    - by Will Eddins
    I'm looking at implementing a live voting system on my website. The website provides a live stream, and I'd like to be able to prompt viewers to select an answer during a vote initiated by the caster. I can understand how to store the data in a mySQL database, and how to process the answers. However: How would I initially start the vote on the client-side and display it? Should a script be running every few seconds on the page, checking another page to see if a question is available for the user? Are there any existing examples of a real-time polling system such as what I'm looking at implementing?

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  • When NOT to use MVVM?

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

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  • New or not so well-known paradigms, syntax features and behaviours of programming languages?

    - by George B
    I've designed some educational programming languages and interpreters for them, but my problem always was that they ended up "normal" and "boring", mostly similar to some kind of existing language (ASM and BASIC). I find it really hard to come up with new ideas for syntax features, "neat things" and new or very modified programming paradigms for it. I always thought that it was hard to come up with good new things not fun/useless new things for this case. I wondered if you could help me out with your creativity: What features in terms of language syntax and built-in functions as well as maybe even new paradigms can I work into my language to keep it useless but more fun, enjoyable, interesting and/or different to program in?

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  • Buffering db inserts in multithreaded program

    - by Winter
    I have a system which breaks a large taks into small tasks using about 30 threads as a time. As each individual thread finishes it persists its calculated results to the database. What I want to achieve is to have each thread pass its results to a new persisance class that will perform a type of double buffering and data persistance while running in its own thread. For example, after 100 threads have moved their data to the buffer the persistance class then the persistance class swaps the buffers and persists all 100 entries to the database. This would allow utilization of prepared statements and thus cut way down on the I/O between the program and the database. Is there a pattern or good example of this type of multithreading double buffering?

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  • How to represent a Many-To-Many relationship in XML or other simple file format?

    - by CSharperWithJava
    I have a list management appliaction that stores its data in a many-to-many relationship database. I.E. A note can be in any number of lists, and a list can have any number of notes. I also can export this data to and XML file and import it in another instance of my app for sharing lists between users. However, this is based on a legacy system where the list to note relationship was one-to-many (ideal for XML). Now a note that is in multiple lists is esentially split into two identical rows in the DB and all relation between them is lost. Question: How can I represent this many-to-many relationship in a simple, standard file format? (Preferably XML to maintain backwards compatibility)

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  • Function chaining depending on boolean result

    - by Markive
    This is just an efficiency question really.. I'm interested to know if there is a more efficient or logical way that people use to handle this sort of scenario. In my asp.net application I am running a script to generate a new project my code at the top level looks like this: Dim ok As Boolean = True ok = createFolderStructure() If ok Then ok = createMDB() If ok Then ok = createProjectConfig() If ok Then ok = updateCompanyConfig() I create a boolean and each function returns a boolean result, the next function in this chain will only run if the previous one was successful. I do this because an asp.net application will continue to run through the page life cycle unless there is an unhandled exception and I don't want my whole application to be screwed up if something in the chain goes wrong (there is a lot of copying and deleting of files etc.. in this example). I was just wondering how other people handle this scenario? the vb.net single line if statement is quite succinct but I'm wondering if there is a better way?

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  • Table with unequal rows in XUL layout

    - by Michael
    Trying to get something similar for Firefox extension using XUL. The most difficult part is the grid with unequal number of rows. I tried <grid> but it didn't work well. Also don't want to use HTML inside of XUL. Any ideas how to build such table?

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

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

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  • Compressing a database to a single file?

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

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  • How would I implement separate databases for reading and writing operations?

    - by Matt
    I am interested in implementing an architecture that has two databases one for read operations and the other for writes. I have never implemented something like this and have always built single database, highly normalised systems so I am not quite sure where to begin. I have a few parts to this question. 1. What would be a good resource to find out more about this achitecture? 2. Is it just a question of replicating between two identical schemas, or would your schemas differ depending on the operations, would normalisation vary too? 3. How do you insure that data written to one database is immediately available for reading from the second? Any further help, tips, resources would be appreciated. Thanks.

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  • How to find the entity with the greatest primary key?

    - by simpatico
    I've an entity LearningUnit that has an int primary key. Actually, it has nothing more. Entity Concept has the following relationship with it: @ManyToOne @Size(min=1,max=7) private LearningUnit learningUnit; In a constructor of Concept I need to retrieve the LearningUnit with the greatest primary key. If no LearningUnit exists yet I instantiate one. I then set this.learningUnit to the retrieved/instantied. Finally, I call the empty constructor of Concept in a try-catch block, to have the entitymanager do the cardinality check. If an exception is thrown (I expect one in the case that already another 7 Concepts are referring to the same LearningUnit. In that case, I case instantiate a new LearningUnit with a new greater primary key. Please, also point out, if any, clear pitfalls in my outlined algorithm above.

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  • Why Do Programmers Get So Invested in their Favorite Technologies?

    - by Pierreten
    I've noticed this culture surrounding Ruby where developers truly believe that they are somehow more gifted than developers of other languages, regardless of experience and talent (even when that isn't the case, I've met some extremely junior Ruby developers come up with some pretty basic constructs, and pass them off as some sort of revolutionary idea). The derision of strongly typed languages seems to be a common theme as well; regardless of its merits. Is there something particular to the Ruby syntax in general that is to account for this? Is there a sociological component to it?

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  • Application that depends heavily on stored procedures

    - by PieterG
    We currently have an application that depends largely on stored procedures. There is a heavy use of temp tables. It's an extremely large application. Facing this situation, I would like to use Entity Framework or Linq2Sql for a rewrite. I might consider using Fluent Hibernate or Subsonic, as i've used them quite extensively in the past. I've had problems with Linq2Sql generating the return types for the stored procedures because of the usage of the temp tables, and I think it's cumbersome to go and change all the stored procedures from temp tables to in-memory tables. Considering the 2 choices that I want to make, which one of the 2 is the best route to go and why? If my choices are extremely idiotic, please provide alternatives. Edit: The reason for the question and the change is that the data access layer is non-existent and was built 10 years ago. We currently still run into a lot of issues with it. I don't want to divulge too much, but if you saw it, your eyes would start bleeding :)

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