Search Results

Search found 30474 results on 1219 pages for 'relational database'.

Page 598/1219 | < Previous Page | 594 595 596 597 598 599 600 601 602 603 604 605  | Next Page >

  • Getting the last element of a Postgres array, declaratively

    - by Wojciech Kaczmarek
    How to obtain the last element of the array in Postgres? I need to do it declaratively as I want to use it as a ORDER BY criteria. I wouldn't want to create a special PGSQL function for it, the less changes to the database the better in this case. In fact, what I want to do is to sort by the last word of a specific column containing multiple words. Changing the model is not an option here. In other words, I want to push Ruby's sort_by {|x| x.split[-1]} into the database level. I can split a value into array of words with Postgres string_to_array or regexp_split_to_array functions, then how to get its last element?

    Read the article

  • How should I capture clickstream data?

    - by editor
    I'd like to start using clickstream analysis to improve a dynamic site's user experience. I'd like to rule out two options: parameterizing URLs (index.php?src=http://www.example.com) and immediate database logging. The former makes pretty ugly URLs and isn't great for SEO and the latter might slow down page render when there are lots of concurrent users. Assuming these aren't viable options, I think I'm left with doing an asynchronous POST to a server side script that runs a database query and returns a 204 (no data) response. Is this the best option for capturing clickstream data?

    Read the article

  • Design question?

    - by Mohamed
    I am building music app, where user can do several tasks including but not limited to listening song, like song, recommend song to a friend and extra. currently I have this model: class Activity(models.Model): activity = models.TextField() user = models.ForeignKey(User) date = models.DateTimeField(auto_now=True) so far I thought about two solutions. 1. saving a string to database. e.g "you listened song xyz" 2. create a dictionary about the activity and save to the database using pickle or json. e.g. dict_ = {"activity_type":"listening", "song":song_obj} I am leaning to the second implementation, but not quite sure. so what do you think about those two methods? do you know better way to achieve the goal?

    Read the article

  • overlay items from mysql

    - by user1285471
    I have several locations in tables in a mysql database which i want to have displayed as POI's, the table is too large and changes too frequently to use sql lite so i need to get the info from mysql. I have set up a mapView indicating the device location in mapview using an image at drawable, but i now need to ad the other locations from the database. Then when a user clicks on an item i need a popup with options to route there using google maps navigation, or view mobi site, phone, or email. I am new to android. Please assist. Have gone through the overlay tut but no indication on how to get the info from db. Is there a tut somwhere so i can see some example code to do this?

    Read the article

  • Using memcached/APC for session storage?

    - by Industrial
    Hi everybody, I had some thoughts back ago about using memcached for session storage, but came to the conclusion that it wouldn't be sufficient in the event of one or more of the servers in the memcached pool were about to go down. A hybrid version is to save the main database (mySQL) from load caused by reads would be to work out a function that tries to fetch the data from the cache pool, and if that fails gets it from the database. After putting some more thought into it, I started to think about using APC cache for session related data. If our web server would go down, sessions would be lost either way, so storing them in a local APC or a localhost memcached server maybe isn't that bad? What's your experiences?

    Read the article

  • Table Adaptor Error when trying update

    - by JasonMc92
    Hi, I have a rather perplexing issue. I am using VB.net and SQL for my project. I have a database, to which the connection works. I also have a data table and data adaptor, both of which I know work. I am trying to update something in the database, yet it isn't working. Assume everything listed is declared correctly. What am I doing wrong? teacher_control_table.Rows(0)("DATA_TeacherLockPasscode") = txtPasscode1.Text table_adaptor2.Update(teacher_control_table) That last line throws the following exception: InvalidOperationException was unhandled. update requires a valid UpdateCommand when passed DataRow collection with modified rows.

    Read the article

  • sql: DELETE + INSERT vs UPDATE + INSERT

    - by user93422
    A similar question has been asked, but since it always depends, I'm asking for my specific situation separately. I have a web-site page that shows some data that comes from a database, and to generate the data from that database I have to do some fairly complex multiple joins queries. The data is being updated once a day (nightly). I would like to pre-generate the data for the said view to speed up the page access. For that I am creating a table that contains exact data I need. Question: for my situation, is it reasonable to do complete table wipe followed by insert? or should I do update,insert? SQL wise seems like DELETE + INSERT will be easier (it is single SQL expression). EDIT: RDBMS: MS SQL Server 2008 Ent

    Read the article

  • Will lock() statement block all threads in the proccess/appdomain?

    - by MikeJ
    Maybe the question sounds silly, but I don't understand 'something about threads and locking and I would like to get a confirmation (here's why I ask). So, if I have 10 servers and 10 request in the same time come to each server, that's 100 request across the farm. Without locking, thats 100 request to the database. If I do something like this: private static readonly object myLockHolder = new object(); if (Cache[key] == null) { lock(myLockHolder) { if (Cache[key] == null) { Cache[key] = LengthyDatabaseCall(); } } } How many database requests will I do? 10? 100? Or as much as I have threads?

    Read the article

  • Have an external java application by notified of changes to Entity EJBs in JBoss AS

    - by John
    I'm trying to connect an external application to a JBoss AS container. The external application is a Java application that is currently being notified of changes to database entities through a JMS topic. I've added an EntityLifecycleListener class to all my entities that publishes a serialized (and unwrapped) copy of the entity to the JMS topic. The problem is that this implementation ignores the transaction boundaries of the JBoss container. For example, the @PostUpdate event can be fire, generating the JMS message for that entity, but the transaction could be rolled back causing the external application to be notified of an invalid change and become unsync'd. I need my external application to only be notified of successful commits to the database, but I need to be able to publish the entire java POJO to the external application. Is there an official way of doing this?

    Read the article

  • Improving the performance of an nHibernate Data Access Layer.

    - by Amitabh
    I am working on improving the performance of DataAccess Layer of an existing Asp.Net Web Application. The scenerios are. Its a web based application in Asp.Net. DataAccess layer is built using NHibernate 1.2 and exposed as WCF Service. The Entity class is marked with DataContract. Lazy loading is not used and because of the eager-fetching of the relations there is huge no of database objects are loaded in the memory. No of hits to the database is also high. For example I profiled the application using NHProfiler and there were about 50+ sql calls to load one of the Entity object using the primary key. I also can not change code much as its an existing live application with no NUnit test cases at all. Please can I get some suggestions here?

    Read the article

  • Copy a Table's data from a Stored Procedure

    - by Niike2
    I am learning how to use SQL and Stored Procedures. I know the syntax is incorrect: Copy data from one table into another table on another Database with a Stored Procedure. The problem is I don't know what table or what database to copy to. I want it to use parameters and not specify the columns specifically. I have 2 Databases (Master_db and Master_copy) and the same table structure on each DB. I want to quickly select a table in Master_db and copy that table's data into Master_copy table with same name. I have come up with something like this: USE Master_DB CREATE PROCEDURE TransferData DEFINE @tableFrom, @tableTo, @databaseTo; INSERT INTO @databaseTo.dbo.@databaseTo SELECT * FROM Master_DB.dbo.@tableFrom GO;

    Read the article

  • Using Forms authentication with remote auth system?

    - by chobo
    I am working on a website that uses a remote websites database to check for authentication (they are both share some database tables, but are separate website...) Right now I check the username and password against the remote websites account / member table, if there is a match I create a session. Questions: Is this secure? On authenticated pages I just check if a session of a specific type exists.Is it possible for someone to create an empty session or something that could bypass this? Is it possible to use Forms authentication with this setup? Right now if a user is authenticated I just get an object back with the username, email and id.

    Read the article

  • How to persist every new entity?

    - by simpatico
    I expect every instantiated entity to correspond to a tuple (& co) in the database. In the examples I see around, one always instantiates the entity (via a constructor) and then calls persist with that entity. I find this error-prone, and was wondering if it wasn't possible to have every instantiated entity automatically managed/persisted/reflected to the database (at least intended to). This also seems to prevent me from persisting instance variable entities. I.e. I've an entity which instantiates another (entities it has an association with) in its constructor.

    Read the article

  • Would like help with LOGON Trigger

    - by Risho
    I've created a logon trigger in MS SQL that needs to check dm_exec_sessions for a login. This login is the user listed in the connection string and has owner right to the database. If the login is verified, I need it to update a specific table and send an email. So far I've done just the following piece and it disabled my web site. The error I get is: "Logon failed for login 'dev' due to trigger execution. Changed database context to 'mydatabase'. Changed language setting to us_english." Any idea what I did wrong? Thanks, Risho CREATE TRIGGER TDY_Assets_Notification ON ALL SERVER WITH EXECUTE AS 'dev' FOR LOGON AS BEGIN IF ORIGINAL_LOGIN()='dev' AND (SELECT COUNT(*) FROM sys.dm_exec_sessions WHERE is_user_process = 1 AND original_login_name = 'dev') > 1 UPDATE Assets_TDY SET Suspense = 1, Warning = 1 WHERE (Date_Returned IS NULL) AND (GETDATE() >= DATEADD(day, 3, Date_Return)) END

    Read the article

  • Saving data that is in a table efficiently and also is easy to retrieve and echo back out

    - by Harry
    Information I currently have a table which image is below, Problem I have made this table using ul & li Here is the code http://jsfiddle.net/8j2qe/1/ Question What would be the best way of storing the data in the image and easily displaying it? Keeping in mind that each column can only have 1 entry. Thank you! And any questions will be answered ASAP! EDIT Sorry, I dont think I was clear enough in my initial question. What I am asking is, what is the best way to store and then display this type of data. I want to DISPLAY data from my database to show like it would in the image. Should I have a column in my database for each column on the table, then say either A,B,C or D depending on what column it is in but then how would I display it using PHP in my code provided? Im struggling to find a good way of explaining this, I am sorry.

    Read the article

  • Searching a Better Solution with Delegates

    - by spagetticode
    Hey All, I am a newbie in C# and curious about the better solution of my case. I have a method which gets the DataTable as a parameter and creates a List with MyClass's variables and returns it. public static List<Campaigns> GetCampaignsList(DataTable DataTable) { List<Campaigns> ListCampaigns = new List<Campaigns>(); foreach (DataRow row in DataTable.Rows) { Campaigns Campaign = new Campaigns(); Campaign.CampaignID = Convert.ToInt32(row["CampaignID"]); Campaign.CustomerID = Convert.ToInt32(row["CustomerID"]); Campaign.ClientID = Convert.ToInt32(row["ClientID"]); Campaign.Title = row["Title"].ToString(); Campaign.Subject = row["Subject"].ToString(); Campaign.FromName = row["FromName"].ToString(); Campaign.FromEmail = row["FromEmail"].ToString(); Campaign.ReplyEmail = row["ReplyEmail"].ToString(); Campaign.AddDate = Convert.ToDateTime(row["AddDate"]); Campaign.UniqueRecipients = Convert.ToInt32(row["UniqueRecipients"]); Campaign.ClientReportVisible = Convert.ToBoolean(row["ClientReportVisible"]); Campaign.Status = Convert.ToInt16(row["Status"]); ListCampaigns.Add(Campaign); } return ListCampaigns; } And one of my another DataTable method gets the DataTable from the database with given parameters. Here is the method. public static DataTable GetNewCampaigns() { DataTable dtCampaigns = new DataTable(); Campaigns Campaigns = new Campaigns(); dtCampaigns = Campaigns.SelectStatus(0); return dtCampaigns; } But the problem is that, this GetNewCampaigns method doesnt take parameters but other methods can take parameters. For example when I try to select a campaign with a CampaignID, I have to send CampaignID as parameter. These all Database methods do take return type as DataTable but different number of parameters. public static DataTable GetCampaignDetails(int CampaignID) { DataTable dtCampaigns = new DataTable(); Campaigns Campaigns = new Campaigns(); dtCampaigns = Campaigns.Select(CampaignID); return dtCampaigns; } At the end, I want to pass a Delegate to my first GetCampaignList Method as parameter which will decide which Database method to invoke. I dont want to pass DataTable as parameter as it is newbie programming. Could you pls help me learn some more advance features. I searched over it and got to Func< delegate but could not come up with a solution.

    Read the article

  • How do manage the limit of executions to be done by hour (Max: 1000 requests per hour) without a dat

    - by cslavoie
    I am currently developing a script in PHP to fetch webpages. The fact is that by doing so, I occasionally do too much requests to a particular website. In order to control any overflow, I would like to keep trace of how many requests have been done in the last hour or so for each domain. It doesn't need to be perfect, just a good estimate. I doesn't have access to a database, except sqlite2. I would really like something really simple because there will typically be a lot of updates, which is kind of heavy for a sqlite database. If no one has a magical solution, I'll go for sqlite, but I was curious what you can come up with Thank you very much

    Read the article

  • How do I make a lock that allows only ONE thread to read from the resource ?

    - by mare
    I have a file that holds an integer ID value. Currently reading the file is protected with ReaderWriterLockSlim as such: public int GetId() { _fileLock.EnterUpgradeableReadLock(); int id = 0; try { if(!File.Exists(_filePath)) CreateIdentityFile(); FileStream readStream = new FileStream(_filePath, FileMode.Open, FileAccess.Read); StreamReader sr = new StreamReader(readStream); string line = sr.ReadLine(); sr.Close(); readStream.Close(); id = int.Parse(line); return int.Parse(line); } finally { SaveNextId(id); // increment the id _fileLock.ExitUpgradeableReadLock(); } } The problem is that subsequent actions after GetId() might fail. As you can see the GetId() method increments the ID every single time, disregarding what happens after it has issued an ID. The issued ID might be left hanging (as said, exceptions might occur). As the ID is incremented, some IDs might be left unused. So I was thinking of moving the SaveNextId(id) out, remove it (the SaveNextId() actually uses the lock too, except that it's EnterWriteLock). And call it manually from outside after all the required methods have executed. That brings out another problem - multiple threads might enter the GetId() method before the SaveNextId() gets executed and they might all receive the same ID. I don't want any solutions where I have to alter the IDs after the operation, correcting them in any way because that's not nice and might lead to more problems. I need a solution where I can somehow callback into the FileIdentityManager (that's the class that handles these IDs) and let the manager know that it can perform the saving of the next ID and then release the read lock on the file containing the ID. Essentialy I want to replicate the relational databases autoincrement behaviour - if anything goes wrong during row insertion, the ID is not used, it is still available for use but it also never happens that the same ID is issued. Hopefully the question is understandable enough for you to provide some solutions..

    Read the article

  • Need help with Excel 2007 Formula - Many to many update

    - by Monica
    I'm experienced with database development, but not so much with Excel. I'm looking for help writing an Excel formula that would help my client's spreadsheet behave like a database. This is what I'm looking to do, but I can't figure out how to write it in Excel 2007: "If Q4 (on sheet 2) contains A2 (on sheet 1), append A1 (on sheet 1) with Q5 (on sheet 2)" Some factors: 1) This formula may find multiple instances of A2, so it should not stop after finding the first match 2) The values, as they are created in A1, should be separated with comma and space 3) This is a many to many relationship between Q4 and A2 Thanks for any help with this. I've tried vlookups, match, if statements, but they all fall short in one way or another.

    Read the article

  • Large number of tables and Hibernate memory consumption

    - by Vedran
    I'm working on a large ERP project which has database model with about 2100 tables. With "only" 500 tables mapped with Hibernate, application deployed on the web server takes about 3GB of working memory. Is there any way to reduce Hibernate's metamodel memory footprint when using that many tables in one persistence unit? Or should I just give up on ORMs and go with plain old JDBC (or even jOOQ)? Right now I'm using Hibernate 4.1.8, Spring 3.1.3, JBoss AS 7.1 and working with MSSQL database. Edit: JavaMelody memory histogram output - with 2000 generated test tables that are a bit smaller in scope from the original db model (hence 'only' 1.3GB of spent memory)

    Read the article

  • Can I use Cassandra to store objects?

    - by Sandeep
    Hi, My application works like this. A database(Mysql) where there is a command. The command is an object(consists of fields many fields like ints ans strings). There is a webservice which interact with the database and get the command from the db and performs some operation. The way how I am storing the command into db is by stripping all the fields and inserting them in to the db. Can I use cassandra in place of mysql and store the command object?

    Read the article

  • Linq to Sql query reuse

    - by UserControl
    Let's say we have a view V1 and V2 that is declared like: create view V2 as select V1.*, V2.C1, V2.C2, V2.C3 from V1 join V2 on V1.Key = V2.Key where bla-bla So V2 narrows down the result set of V1 and adds some joins. And there is a retrieval routine in C# IEnumerable<V1> GetData(MyFilter filter, MySortOrder order) {} I want to reuse with V2. Is it possible without performing joins in L2S rather than in database? Should i manually create a base class in the database context or something?

    Read the article

  • Is directly executing SQL bad app design?

    - by Michael Lowman
    I'm developing an iOS application that's a manager/viewer for another project. The idea is the app will be able to process the data stored in a database into a number of visualizations-- the overall effect being similar to cacti. I'm making the visualizations fully user-configurable: the user defines what she wants to see and adds restrictions. She might specify, for instance, to graph a metric over the last three weeks with user accounts that are currently active and aren't based in the United States. My problem is that the only design I can think of is more or less passing direct SQL from the iOS app to the backend server to be executed against the database. I know it's bad practice and everything should be written in terms of stored procedures. But how else do I maintain enough flexiblity to keep fully user-defined queries? While the application does compose the SQL, direct SQL is never visible or injectable by the user. That's all abstracted away in UIDateTimeChoosers, UIPickerViews, and the like.

    Read the article

  • Mass data store with SQL SERVER

    - by Leo
    We need management 10,000 GPS devices, each GPS device upload a GPS data every 30 seconds, these data need to store in the database(MS SQL Server 2005). Each GPS device daily data quantity is: 24 * 60 * 2 = 2,880 10 000 10,000 GPS devices daily data quantity is: 10000 * 2880 = 28,800,000 Each GPS data approximately 160Byte, the amount of data per day is: 28,800,000 * 160 = 4.29GB We need hold at least 3 months of GPS data in the database, My question is: 1, whether SQL Server 2005 can support such a large amount of data store? 2, How to plan data table? (all GPS data storage in one table? Daily table? Each GPS device with a GPS data table?) The GPS data: GPSID varchar(21), RecvTime datetime, GPSTime datetime, IsValid bit, IsNavi bit, Lng float, Lat float, Alt float, Spd smallint, Head smallint, PulseValue bigint, Oil float, TSW1 bigint, TSW1Mask bigint, TSW2 bigint, TSW2Mask, BSW bigint, StateText varchar(200), PosText varchar(200), UploadType tinyint

    Read the article

< Previous Page | 594 595 596 597 598 599 600 601 602 603 604 605  | Next Page >