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  • how to synchronize database table and directory with php

    - by twmulloy
    hello, I have a directory with files and a database table with what should be the same files. I would like to be able to synchronize the database table with the directory. What would be the most efficient way to do this? or would I realistically only be able to do this in a brute manner? Here's my approach: 1. retrieve all of the files in the directory as array 2. retrieve all of the filenames in the database table as array 3. loop through the file values in the directory array and use in_array() on the database table array to verify the filename is in that array, and if not then start building an array to insert the missing filenames. run db query to add each missing file row to database table 4. loop through directory array and use in_array() on the directory array and anything not found in the directory array will just be deleted from the table. Is there a better way to go about this? or something better for this in php than in_array()?

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  • Finding contained bordered regions from Excel imports.

    - by dmaruca
    I am importing massive amounts of data from Excel that have various table layouts. I have good enough table detection routines and merge cell handling, but I am running into a problem when it comes to dealing with borders. Namely performance. The bordered regions in some of these files have meaning. Data Setup: I am importing directly from Office Open XML using VB6 and MSXML. The data is parsed from the XML into a dictionary of cell data. This wonks wonderfully and is just as fast as using docmd.transferspreadsheet in Access, but returns much better results. Each cell contains a pointer to a style element which contains a pointer to a border element that defines the visibility and weight of each border (this is how the data is structured inside OpenXML, also). Challenge: What I'm trying to do is find every region that is enclosed inside borders, and create a list of cells that are inside that region. What I have done: I initially created a BFS(breadth first search) fill routine to find these areas. This works wonderfully and fast for "normal" sized spreadsheets, but gets way too slow for imports into the thousands of rows. One problem is that a border in Excel could be stored in the cell you are checking or the opposing border in the adjacent cell. That's ok, I can consolidate that data on import to reduce the number of checks needed. One thing I thought about doing is to create a separate graph that outlines the cells using the borders as my edges and using a graph algorithm to find regions that way, but I'm having trouble figuring out how to implement the algorithm. I've used Dijkstra in the past and thought I could do similar with this. So I can span out using no endpoint to search the entire graph, and if I encounter a closed node I know that I just found an enclosed region, but how can I know if the route I've found is the optimal one? I guess I could flag that to run a separate check for the found closed node to the previous node ignoring that one edge. This could work, but wouldn't be much better performance wise on dense graphs. Can anyone else suggest a better method? Thanks for taking the time to read this.

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  • How do I force a restore over an existing database?

    - by Ian Boyd
    I have a database, and i want to force a restore over top of it. I check the option: Overwrite the existing database (WITH REPLACE) But, as expected, SSMS is unable to overwrite the existing database. Of course i don't want different filenames; i want to overwrite the existing database. How do i force a restore over an existing database? And for Google search crawler: File '%s' is claimed by '%s'(4) and '%s"(3). The WITH MOVE clause can be used to relocate one or more files. RESTORE DATABASE is terminating abnormally. (Microsoft SQL Server, Error: 3176) Update The script (before i deleted the database, because i needed to get it done) was: RESTORE DATABASE [HealthCareGovManager] FILE = N'HealthCareGovManager_Data', FILE = N'HealthCareGovManager_Archive', FILE = N'HealthCareGovManager_AuditLog' FROM DISK = N'D:\STAGING\HealthCareGovManager10232013.bak' WITH FILE = 1, MOVE N'HealthCareGovManager_Data' TO N'D:\CGI Data\HealthCareGovManager.MDF', MOVE N'HealthCareGovManager_Archive' TO N'D:\CGI Data\HealthCareGovManager.ndf', MOVE N'HealthCareGovManager_AuditLog' TO N'D:\CGI Data\HealthCareGovManager.ndf', MOVE N'HealthCareGovManager_Log' TO N'D:\CGI Data\HealthCareGovManager.LDF', NOUNLOAD, REPLACE, STATS = 10 I used the UI to delete the existing database, so that i could use the UI to force an overwrite of the (non)existing database. Hopefully there can be an answer so that the next guy can have an answer. No, nobody was in the context of the database (The error message from other connections is quite different from this error, and i only got to see this error after i killed the other connections).

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  • Can an algorithmic process ever give true random numbers ?

    - by Arkapravo
    I have worked with random functions in python,ruby, MATLAB, Bash and Java. Nearly every programming language has a function to generate Random numbers. However, these apparently random sequences are termed as pseudo-random number sequences as the generation follows a deterministic approach, and the sequence seems to repeat (usually with a very large period). My question, can an algorithmic/programming process ever yield true random numbers ? The questions probably is more of theoretical computer science than just programming !

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  • Mutual Information / Entropy Calculation Help

    - by Fillip
    Hi, Hoping someone can give me some pointers with this entropy problem. Say X is chosen randomly from the uniform integer distribution 0-32 (inclusive). I calculate the entropy, H(X) = 32 bits, as each Xi has equal probability of occurring. Now, say the following pseudocode executes. int r = rand(0,1); // a random integer 0 or 1 r = r * 33 + X; How would I work out the mutual information between the two variables r and X? Mutual Information is defined as I(X; Y) = H(X) - H(X|Y) but I don't really understand how to apply the conditional entropy H(X|Y) to this problem. Thanks

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  • logfile deleted on Oracle database how to re-create it?

    - by Daniel
    for my database assignment we were looking into 'database corruption' and I was asked to delete the second redo log file which I have done with the command: rm log02a.rdo this was in the $HOME/ORADATA/u03 directory. Now I started up my database using startup pfile=$PFILE nomount then I mounted it using the command alter database mount; now when I try to open it alter database open; it gives me the error: ORA-03113: end-of-file on communication channel Process ID: 22125 Session ID: 25 Serial number: 1 I am assuming this is because the second redo log file is missing. There is still log01a.rdo, but not the one I have deleted. How can I go about recovering this now so that I can open my database again? I have looked into the database created scripts, and it specified the log02a.rdo file to be size 10M and part of group 2. If I do select group#, member from v$logfile; I get: 1 /oradata/student_db/user06/ORADATA/u03/log01a.rdo 2 /oradata/student_db/user06/ORADATA/u03/log02a.rdo 3 /oradata/student_db/user06/ORADATA/u03/log03a.rdo 4 /oradata/student_db/user06/ORADATA/u03/log04a.rdo So it is part of group 2. If I try to add the log02a.rdo file again "already part of the database". If I drop group 2 and then add it again with these commands: ALTER DATABASE ADD LOGFILE GROUP 2 ('$HOME/ORADATA/u03/log02a.rdo') SIZE 10M; Nothing. Supposedly alters the database, but it still won't start up. Any ideas what I can do to re-create this and be able to open my database again?

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  • XCode copies blank database when doing build...

    - by Incognitii
    I've noticed that even though I placed my sqlite3 database in the "resources" folder, and even though I checked the "Copy file" box, when I do a build, XCode creates an empty database toi the application folder it's building...so it's FINDING the database, and OPENING it, but there's nothing IN it, so when I do a sqlite3_prepare_v2, I get a SQLITE_ERROR... Help! What am I doing wrong?

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  • Oracle database link

    - by Sunit
    I'm currently using Windows Authentication with 2 Oracle servers - SP3DSMP1 & SP3DSMP4. I created a database link on SMP1 to connect to SMP4 as: SQL create public database link LINK_SMP4 2 connect to CURRENT_USER 3 using 'SP3DSMP4'; Database link created. However when I try to do a query, I get the error: ERROR at line 1: ORA-01017: invalid username/password; logon denied Any ideas what might be wrong here? thanks Sunit

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  • Database.ExecuteNonQuery does not return

    - by dan-waterbly
    I have a very odd issue. When I execute a specific database stored procedure from C# using SqlCommand.ExecuteNonQuery, my stored procedure is never executed. Furthermore, SQL Profiler does not register the command at all. I do not receive a command timeout, and no exeception is thrown. The weirdest thing is that this code has worked fine over 1,200,000 times, but for this one particular file I am inserting into the database, it just hangs forever. When I kill the application, I receive this error in the event log of the database server: "A fatal error occurued while reading the input stream from the network. The session will be terminated (input error: 64, output error: 0). Which makes me think that the database server is receiving the command, though SQL Profiler says otherwise. I know that the appropiate permissions are set, and that the connection string is right as this piece of code and stored procedure works fine with other files. Below is the code that calls the stored procedure, it may be important to note that the file I am trying to insert is 33.5MB, but I have added more than 10,000 files larger than 500MB, so I do not think the size is the issue: using (SqlConnection sqlconn = new SqlConnection(ConfigurationManager.ConnectionStrings["TheDatabase"].ConnectionString)) using (SqlCommand command = sqlconn.CreateCommand()) { command.CommandText = "Add_File"; command.CommandType = CommandType.StoredProcedure; command.CommandTimeout = 30 //should timeout in 30 seconds, but doesn't... command.Parameters.AddWithValue("@ID", ID).SqlDbType = SqlDbType.BigInt; command.Parameters.AddWithValue("@BinaryData", byteArr).SqlDbType = SqlDbType.VarBinary; command.Parameters.AddWithValue("@FileName", fileName).SqlDbType = SqlDbType.VarChar; sqlconn.Open(); command.ExecuteNonQuery(); } There is no firewall between the server making the call and the database server, and the windows firewalls have been disabled to troubleshoot this issue.

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  • connecting to phpMyAdmin database with PHP/MySQL

    - by user303955
    I've made a database using phpMyAdmin , now I want to make a register form for my site where peaple can register .I know how to work with input tags in HTML and I know how to insert data into a database but my problem is that I don't know how I can connect to the database that is already made in phpMyAdmin.

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  • How to Shrink Transaction log in sql server database in replication

    - by Renju
    Hi I'm having a production database and its replicated report database. How to shrink the transaction log files in the production database as the log file size is increasing. I had tried DBCC SHRINKFILE and SHRINKDATABASE commands but it does not work for me. I can't detach and shrink and attach back as the db in replication. Please help me in this issue.

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  • Algorithm for Determining Variations of Differing Lengths

    - by joseph.ferris
    I have four objects - for the sake of arguments, let say that they are the following letters: A B C D I need to calculate the number of variations that can be made for these under the following two conditions: No repetition Objects are position agnostic Taking the above, this means that with a four object sequence, I can have only one sequence that matches the criteria (since order is not considered for being unique): ABCD There are four variations for a three object combination from the four object pool: ABC, ABD, ACD, and BCD There are six variations for a two object combination from the four object pool: AB, AC, AD, BC, BD, and CD And the most simple one, if taken on at a time: A, B, C, and D I swear that this was something covered in school, many, many years ago - and probably forgotten since I didn't think I would use it. :-) I am anticipating that factorials will come into play, but just trying to force an equation is not working. Any advice would be appreciated.

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  • Comparing date in access database

    - by Simon
    How can i compare the day in the access database to a given day in c#? The date column in the database is an general date(day/month/year) try { database = new OleDbConnection(connectionString); database.Open(); date = DateTime.Now.ToShortDateString(); string queryString = "SELECT user_name,zivila.naziv " + "FROM (users LEFT JOIN obroki_save ON obroki_save.ID_uporabnika=users.ID)" + " LEFT JOIN zivila ON zivila.ID=obroki_save.ID_zivila " + " WHERE users.ID= " + a.ToString() + " AND obroki_save.datum=# " + date; loadDataGrid(queryString); } catch (Exception ex) { MessageBox.Show(ex.Message); return; }

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  • What is the difference between causal models and directed graphical models?

    - by Neil G
    What is the difference between causal models and directed graphical models? or: What is the difference between causal relationships and directed probabilistic relationships? or, even better: What would you put in the interface of a DirectedProbabilisticModel class, and what in a CausalModel class? Would one inherit from the other? Collaborative solution: interface DirectedModel { map<Node, double> InferredProbabilities(map<Node, double> observed_probabilities, set<Node> nodes_of_interest) } interface CausalModel: DirectedModel { bool NodesDependent(set<Node> nodes, map<Node, double> context) map<Node, double> InferredProbabilities(map<Node, double> observed_probabilities, map<Node, double> externally_forced_probabilities, set<Node> nodes_of_interest) }

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  • Object responsibilities - list and item

    - by Mark Tyler
    My question is more like a theoretical. Say you have an object, that represents the list of something (articles, pages, accounts etc.) class ObjCollection You have a class, that represents a specific item in collection: class objItem I have a problem thinking of a basic responsibilities of each object. Which class is responsible for creating a new objItem? Which class is responsible for deleting a objItem? Should it delete itself as a method?

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  • the problem only happens when i try create a release...

    - by ace
    I'm sorry if im not presenting this right, but i trully cannot understand what the problem is. i have a project to hand in, a code of 600 lines defined within a main, .cpp, and header file. if i compile the project with just a debugger and no release, it's fine. when i create it with the release, the following error occurs, for every function!!! 1st error: |36|multiple definition of `countLines(int&, std::vector const&)'| 2nd error: |36|first defined here| if someone will allow me and i can send them the entire code, that would be awesome - i have to have this done within 3 hours.

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  • P=NP?-Problem: What are the most promising methods?

    - by phimuemue
    Hello everybody, I know that P=NP has not been solved up to now, but can anybody tell me something about the following: What are currently the most promising mathematical / computer scientific methods that could be helpful to tackle this problem? Or are there even none such methods known to be potentially helpful up to now? Is there any (free) compendium on this topic where I can find all / most of the research done in this area?

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  • Adjusting for compass wrap around in a navigation application

    - by chris12892
    I have a application where I am guiding a vehicle on compass headings and I am having an issue when the vehicle is crossing from 360 degrees to 0 degrees. In this case, there are no smarts in the control loop to compute that the nearest way to turn to follow a heading. For example, if the vehicle is instructed to follow a heading of 360 degrees, it will inevitably drifts a few degrees to ether side. If it drifts over to 0+ degrees, the control loop will go nuts and try to steer the vehicle all the way around to get it to 360 degrees again. Is there a graceful way to deal with this? The way the navigate function is written, I use an external PID controller class and I calculate the heading like this: lock (steering) { if (!Engaged) { return; } double mv = 90 + Trim + pidController.CalculateCorrection(flyHeading, currentHeading); steering.Degree = mv; } Thanks!

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  • SQL Server architecture guidance

    - by Liam
    Hi, We are designing a new version of our existing product on a new schema. Its an internal web application with possibly 100 concurrent users (max)This will run on a SQL Server 2008 database. On of the discussion items recently is whether we should have a single database of split the database for performance reasons across 2 separate databases. The database could grow anywhere from 50-100GB over 5 years. We are Developers and not DBAs so it would be nice to get some general guidance. [I know the answer is not simple as it depends on the schema, archiving policy, amount of data etc. ] Option 1 Single Main Database [This is my preferred option]. The plan would be to have all the tables in a single database and possibly to use file groups and partitioning to separate the data if required across multiple disks. [Use schema if appropriate]. This should deal with the performance concerns One of the comments wrt this was that the a single server instance would still be processing this data so there would still be a processing bottle neck. For reporting we could have a separate reporting DB but this is still being discussed. Option 2 Split the database into 2 separate databases DB1 - Customers, Accounts, Customer resources etc DB2 - This would contain the bulk of the data [i.e. Vehicle tracking data, financial transaction tables etc]. These tables would typically contain a lot of data. [It could reside on a separate server if required] This plan would involve keeping the main data in a smaller database [DB1] and retaining the [mainly] read only transaction type data in a separate DB [DB2]. The UI would mainly read from DB1 and thus be more responsive. [I'm aware that this option makes it harder for Referential Integrity to be enforced.] Points for consideration As we are at the design stage we can at least make proper use of indexes to deal performance issues so thats why option 1 to me is attractive and its more of a standard approach. For both options we are considering implementing an archiving database. Apologies for the long Question. In summary the question is 1 DB or 2? Thanks in advance, Liam

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  • Resource placement (optimal strategy)

    - by blackened
    I know that this is not exactly the right place to ask this question, but maybe a wise guy comes across and has the solution. I'm trying to write a computer game and I need an algorithm to solve this question: The game is played between 2 players. Each side has 1.000 dollars. There are three "boxes" and each player writes down the amount of money he is going to place into those boxes. Then these amounts are compared. Whoever placed more money in a box scores 1 point (if draw half point each). Whoever scores more points wins his opponents 1.000 dollars. Example game: Player A: [500, 500, 0] Player B: [333, 333, 334] Player A wins because he won Box A and Box B (but lost Box C). Question: What is the optimal strategy to place the money? I have more questions to ask (algorithm related, not math related) but I need to know the answer to this one first. Update (1): After some more research I've learned that these type of problems/games are called Colonel Blotto Games. I did my best and found few (highly technical) documents on the subject. Cutting it short, the problem I have (as described above) is called simple Blotto Game (only three battlefields with symmetric resources). The difficult ones are the ones with, say, 10+ battle fields with non-symmetric resources. All the documents I've read say that the simple Blotto game is easy to solve. The thing is, none of them actually say what that "easy" solution is.

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  • SQL Compact Edition database corruption

    - by jdv
    Hi, Our product is using MS SQL Compact Edition on a Windows machine (laptop). It's basically a metadata index for files we have on the filesystem. Recently we have seen databases getting corrupted. This happens when the machine is very busy moving files around and has to do a tiny bit of database changes at the same time. I was somewhat shocked that was at all possible. It was my expectation that the database would stay coherent whatever the circumstances. Of course we are doing something wrong. Things we have checked so far are: Use of only one db connection per thread specify the maximum size when opening the database The database is accessed only by one application, a .net based windows service. Are there other gotcha's?

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  • Make Java parent class not part of the interface

    - by Bart van Heukelom
    (This is a hypothetical question for discussion, I have no actual problem). Say that I'm making an implementation of SortedSet by extending LinkedHashMap: class LinkedHashSortedMapThing extends LinkedHashMap implements SortedSet { ... } Now programmers who use this class may do LinkedHashMap x = new LinkedHashSortedMapThing(); But what if I consider the extending of LinkedHashMap an implementation detail, and do not want it to be a part of the class' contract? If people use the line above, I can no longer freely change this detail without worrying about breaking existing code. Is there any way to prevent this sort of thing, other than favouring composition over inheritance (which is not always possible due to private/protected members)?

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  • Database Design Question: GUID + Natural Numbers

    - by Alan
    For a database I'm building, I've decided to use natural numbers as the primary key. I'm aware of the advantages that GUID's allow, but looking at the data, the bulk of row's data were GUID keys. I want to generate XML records from the database data, and one problem with natural numbers is that I don't want to expose my database key's to the outside world, and allow users to guess "keys." I believe GUID's solve this problem. So, I think the solution is to generate a sparse, unique iD derived from the natural ID (hopefully it would be 2-way), or just add an extra column in the database and store a guid (or some other multibyte id) The derived value is nicer because there is no storage penalty, but it would be easier to reverse and guess compared to a GUID. I'm (buy) curious as to what others on SO have done, and what insights they have.

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