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  • Which upgrade path for disk IO bound postgres server?

    - by user41679
    Hi all, We currently have a Sun x4270 with 2xquad core Xeon Nehalmen 2.93ghz cores (16 threads), 72 gig of ram and 16 x 10k SAS disks split between the os raid 1, a partition for the Write Ahead Logs which is raid 10 and a partition for the database tables and indexes which is also raid 10, all xfs. I'm currently evaluating which path to go down in terms of upgrades. We'll be sharding the DB at some point soon, but for now I need to focus on hardware upgrades specifically. The machine is not CPU or memory bound at all at the moment, just IOWait is become an issue. The machine is mostly write access as we have a heavy caching layer. We're seeing about 300 write IOPS average on both the database partitions. We don't have any additional storage infrastructure like a Fiber Channel or ISCSI network. Budget isn't too much of a concern, something inline with the size of this server (i.e no $1m IBM machines) Space is ok on the DB side of things, we're running out obviously but there's also some reduction we can do. Additional space would be good though. My current thoughts are either: * ISCSI SAN, possible with 10Gbit network that has solid state acceleration. * FusionIO card / Sun F20 card (will the FusionIO card work in the Sun box? * DAS shelf (something like this http://www.broadberry.co.uk/das-direct-attached-storage-servers/cyberstore-224s-das) which a combination of 15k sas disks and some Intel X25-E drives for DB indexes etc) what would I need to put in the x4270 to add a DAS shelf? I think it's a SAS HBA card, do I have to use Sun's own card or will any PCI Express card work? Anything else??? what would you guys do from your experience? I appreciate it's a lot of questions, but I haven't expanded a DB machine for a number of years and the landscape has changed dramatically since then! Any advice or feedback would be very much appreciated. Let me know if there's anything else I can clarify. Thanks in advance!

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  • Scaling databases with cheap SSD hard drives

    - by Dennis Kashkin
    Hey guys! I hope that many of you are working with high traffic database-driven websites, and chances are that your main scalability issues are in the database. I noticed a couple of things lately: Most large databases require a team of DBAs in order to scale. They constantly struggle with limitations of hard drives and end up with very expensive solutions (SANs or large RAIDs, frequent maintenance windows for defragging and repartitioning, etc.) The actual annual cost of maintaining such databases is in $100K-$1M range which is too steep for me :) Finally, we got several companies like Intel, Samsung, FusionIO, etc. that just started selling extremely fast yet affordable SSD hard drives based on SLC Flash technology. These drives are 100 times faster in random read/writes than the best spinning hard drives on the market (up to 50,000 random writes per second). Their seek time is pretty much zero, so the cost of random I/O is the same as sequential I/O, which is awesome for databases. These SSD drives cost around $10-$20 per gigabyte, and they are relatively small (64GB). So, there seems to be an opportunity to avoid the HUGE costs of scaling databases the traditional way by simply building a big enough RAID 5 array of SSD drives (which would cost only a few thousand dollars). Then we don't care if the database file is fragmented, and we can afford 100 times more disk writes per second without having to spread the database across 100 spindles. . Is anybody else interested in this? I've been testing a few SSD drives and can share my results. If anybody on this site has already solved their I/O bottleneck with SSDs, I would love to hear your war stories! PS. I know that there are plenty of expensive solutions out there that help with scalability, for example the time proven RAM-based SANs. I want to be clear that even $50K is too expensive for my project. I have to find a solution that costs no more than $10K and does not take much time to implement.

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  • Script to mirror MS SQL Server databases between 2 servers

    - by David W
    Hi I have about 200 sites each of which have 2 servers running MSSQL (2k5 at some sites, 2k8 at others) One server is production and the other is primarily there as a backup. We're rebuilding all of these servers this year and as part of that we will have to set up mirroring for ... a lot ... of databases. Some of these sites have 45 databases so mirroring them manually is going to be a huge pain. I was going to write a batch script which uses SQLCMD to backup the database and log, copies to the secondary server, restores the backup and log with norecovery, creates the endpoints and sets the partner. This in itself isn't too complicated, but i'd love to see what other people have done as i'm not very confident in catching errors using the process i've outlined above. I've seen Tools to manage sql 2008 database mirroring? Which looks really good, but the formatting is jumbled and I can't get it to work. If anyone has any other scripts they've written and are willing to share I'd be eternally grateful. Ideally I'd love to be able to use a script to ensure there are matching endpoints (same ports) on both servers, backup the database, backup the log, copy the backups to second server, restore database and log with norecovery, set the partners on both servers, and somehow confirm that the databases are linked and synchronized. Well, thanks for reading :)

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  • SQL Server Replication Backup

    - by user18039
    Hi We have a new system that runs on SQL Server 2008 r2 64-bit. There is a primary on-line transactional processing (OLTP) database that accepts a high volume of updates from several thousand Point of Sale systems at stores around the country. In order to protect this vital function, I have decided to introduce a dedicated reporting database server - from which multiple users will run some pretty complex reports. I realise that there were a number of choices but I decided to use Transaction Replication as the mechanism for copying the data from the OLTP database to the new reporting database - one way replication. The solution has worked well in test. I'm now being asked what changes need to be made to the backup policy to cover the architectural changes. I have read pages such as MSDN:Strategies for Backing Up and Restoring Snapshot and Transactional Replication but I think these are overkill for my solution. In fact, my current thinking is that we simply need to continue making backups of the OLTP data and logs. If the Reporting db or any of the system replication (eg distribution) databases fail then it's no big deal - we can clear all down then re-create the replication. I realise that taking a complete snapshot of the OLTP would be time consuming (approx 5 hours) but I'd be more relaxed about this that trying to restore backups of the various data and log files in the correct sequence. My view is that the complex strategies set out in the MSDN article would only be the way to go for a more complex replication solution than I have, eg if there were multiple subscribers with 2-way replication. Would you agree? I'd be grateful for any advice. Many thanks, Rob.,

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  • Which free RDBMS is best for small in-house development?

    - by Nic Waller
    I am the sole sysadmin for a small firm of about 50 people, and I have been asked to develop an in-house application for tracking job completion and providing reports based on that data. I'm planning on building it as a web application. I have roughly equal experience developing for MySQL, PostgreSQL, and MSSQL. We are primarily a Windows-based shop, but I'm fairly comfortable with both Windows and Linux system administration. These are my two biggest concerns: Ease of managability. I don't expect to be maintaining this database forever. For the sake of the person that eventually has to take over for me, which database has the lowest barrier to entry? Data integrity. This means transaction-safe, robust storage, and easy backup/recovery. Even better if the database can be easily replicated. There is not a lot of budget for this project, so I am restricted to working with one of the free database systems mentioned above. What would you choose?

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  • Soapui & populating database before

    - by mada
    SoapUi & database data needed Hi, In a J2ee project( spring ws + hibernate +postgresql+maven 2 + tomcat),We have created webservices with full crud operations. We are currently testing them with SoapUi (not yet integrated in the integration-test maven phase ). We need tomcat to test them. Actually before the phase test, with a maven plugin, only one time, some datas are injected in the database before the launch of all tests through many sql files. But the fact is that to test some webservices i need some data entry & their Id (primary key) A- What is the best way to create them ? 1- populate one of the previous .sql test file. But now we have a big dependency where i have to be careful to use the same id use in a insert in the sql file in SoapUi too. And if any developper drop the value, the test will broke. 2- create amongst the .sql file test a soapui.sql where ALL data needed for the Sopaui test will be concentrated. The advantage is that the maintenance will be much more easy. 3-because i have Ws available for all crud operations, i can create before any testsuite a previous testsuite called setup-testsuiteX. In this one, i will use those Ws to inject datas in the databse & save id in variables thanks to the feature "property transfer" 4-launch the soapui test xml file with a junit java test & in the Setup Method (we are using spring test), we will populate the database with DbUnit. Drawback: they are already data in the database & some conflicts may appear due to constraint.And now i have a dependency between: - dbUnit Xml file (with the value primary key) - sopaui test where THOSe value of primarykey will be used advantage: A automatic rollback is possible for DbUnit Data but i dont know how it will react because those data have been used with the Ws. 5- your suggestion ? better idea ? Testing those Ws create datas in the DB. How is the best way to remove them at the end ? (in how daostest we were using a automatic rollback with spring test to let the database clean) Thanks in advance for your hep & sorry for my english, it is not my mother thongue. Regards.

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  • How to insert a DataTable with existing Key to a SQL Server Table.

    - by user296575
    I am working with VB.NET.. i have a DataTable called "QUESTION", containing 3 fields: QuestionNumber (unique integer key) QuestionText QuestionType In my SQL Server database I created a Table called "QUESTION" with the same fields. QuestionNumber is defined as integer unique key, auto increment Now, when i make a bulk copy to insert the DataTable into the SQL Server, the database overwrites my QuestionNumber from the DataTable and generates new ones (starting from 1 increment 1). How do i have to change my database setup, that the original QuestionNumbers are copied into the database?

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  • Cannot figure out how to take in generic parameters for an Enterprise Framework library sql statemen

    - by KallDrexx
    I have written a specialized class to wrap up the enterprise library database functionality for easier usage. The reasoning for using the Enterprise Library is because my applications commonly connect to both oracle and sql server database systems. My wrapper handles both creating connection strings on the fly, connecting, and executing queries allowing my main code to only have to write a few lines of code to do database stuff and deal with error handling. As an example my ExecuteNonQuery method has the following declaration: /// <summary> /// Executes a query that returns no results (e.g. insert or update statements) /// </summary> /// <param name="sqlQuery"></param> /// <param name="parameters">Hashtable containing all the parameters for the query</param> /// <returns>The total number of records modified, -1 if an error occurred </returns> public int ExecuteNonQuery(string sqlQuery, Hashtable parameters) { // Make sure we are connected to the database if (!IsConnected) { ErrorHandler("Attempted to run a query without being connected to a database.", ErrorSeverity.Critical); return -1; } // Form the command DbCommand dbCommand = _database.GetSqlStringCommand(sqlQuery); // Add all the paramters foreach (string key in parameters.Keys) { if (parameters[key] == null) _database.AddInParameter(dbCommand, key, DbType.Object, null); else _database.AddInParameter(dbCommand, key, DbType.Object, parameters[key].ToString()); } return _database.ExecuteNonQuery(dbCommand); } _database is defined as private Database _database;. Hashtable parameters are created via code similar to p.Add("@param", value);. the issue I am having is that it seems that with enterprise library database framework you must declare the dbType of each parameter. This isn't an issue when you are calling the database code directly when forming the paramters but doesn't work for creating a generic abstraction class such as I have. In order to try and get around that I thought I could just use DbType.Object and figure the DB will figure it out based on the columns the sql is working with. Unfortunately, this is not the case as I get the following error: Implicit conversion from data type sql_variant to varchar is not allowed. Use the CONVERT function to run this query Is there any way to use generic parameters in a wrapper class or am I just going to have to move all my DB code into my main classes?

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  • Should Databases be used just for persistence

    - by Raju
    A lot of web applications having a 3 tier architecture are doing all the processing in the app server and use the database for persistence just to have database independence. After paying a huge amount for a database, doing all the processing including batch at the app server and not using the power of the database seems to be a waste. I have a difficulty in convincing people that we need to use best of both worlds.

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  • data to be saved in SQLite and want to retrive data from there

    - by Mona
    In android, is it possible that we insert our database in SQLite and get back that data on our EditText boxes. I want to get data from database and populate it in my application activity. How can i do that. I want to save, update and delete my database in SQLite and most important i want to get data from database that is saved in SQLite tables. How can it be possible. Kindly guide. I will be thankfull to you

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  • How optimize queries with fully qualified names in t-sql?

    - by tomaszs
    Whe I call: select * from Database.dbo.Table where NAME = 'cat' It takes: 200 ms And when I change database to Database in Management Studio and call it without fully qualified name it's much faster: select * from Table where NAME = 'cat' It takes: 17 ms Is there any way to make fully qualified queries faster without changing database?

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  • Does Doctrine 1.2 support importing indexes with Doctrine_Core::generateModelsFromDb function?

    - by Coagulant
    Does Doctrine 1.2 support importing indexes with Doctrine_Core::generateModelsFromDb() function? I need to make a migration between 2 database connections, one of them having unique index on 2 fields and one doesn't. And my migration is empty. It looks like Doctrine doesn't support indexes when importing from databae, other than those tied to relationship foreign keys. $changes = Doctrine_Core::generateMigrationsFromDiff($migrationsPath, array('doctrineOld'), array('doctrine'));

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  • Help! The log file for database 'tempdb' is full. Back up the transaction log for the database to fr

    - by michael.lukatchik
    We're running SQL Server 2000. In our database, we have an "Orders" table with approximately 750,000 rows. We can perform simple SELECT statements on this table. However, when we want to run a query like SELECT TOP 100 * FROM Orders ORDER BY Date_Ordered DESC, we receive the following message: Error: 9002, Severity: 17, State: 6 The log file for database 'tempdb' is full. Back up the transaction log for the database to free up some log space. We have other tables in our database which are similar in size of the amount of records that are in the tables (i.e. 700,000 records). On these tables, we can run any queries we'd like and we never receive a message about 'tempdb being full'. To resolve this, we've backed up our database, shrunk the actual database and also shrunk the database and files in the tempdb system database, but this hasn't resolved the issue. The size of our log file is set to autogrow. We're not sure where to go next. Are there any ideas why we still might be receiving this message? Error: 9002, Severity: 17, State: 6 The log file for database 'tempdb' is full. Back up the transaction log for the database to free up some log space.

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  • SQLite Step Failed: attempt to write a readonly database , using wrapper

    - by user271753
    I keep getting an error "SQLite Step Failed: attempt to write a readonly database" when using this code to copy a database: -(void)createEditableCopyOfDatabaseIfNeeded { // Testing for existence BOOL success; NSFileManager *fileManager = [NSFileManager defaultManager]; NSError *error; NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:@"Money.sqlite"]; success = [fileManager fileExistsAtPath:writableDBPath]; if (success) return; // The writable database does not exist, so copy the default to // the appropriate location. NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"Money.sqlite"]; success = [fileManager copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error]; if(!success) { NSAssert1(0,@"Failed to create writable database file with Message : '%@'.", [error localizedDescription]); } } I am using the above code in AppDelegate and this: NSString *writableDBPath = [[NSBundle mainBundle] pathForResource:@"Money" ofType:@"sqlite"]; In ViewController.m I am using http://th30z.netsons.org/2008/11/objective-c-sqlite-wrapper/ what am I doing wrong? This is happening again and again... It was working fine before but again the problem started.

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  • flushing database cache in SWI-Prolog

    - by JPro
    We are using swi-prolog to run our testcases. Whenever the test starts, I am opening the connection to MYSQL database and storing the Name of the Test hat is being done and then closing the DB. These tests run for about 2 days continuously. After the tests are done, the results basically gets stored in folder in the server. There is a predicate in another prolog file that is called to update the results to the MYSQL database. The code is simple, I use odbc library and just call odbc_* predicates to connect and update the mysql by issuing direct queries. The actual problem is : If I try to call the Predicate from the same Prolog window, where the test just got completed, I get an error as updating to the DB server. Although I do not get any error in the connection. If I close the session of that prolog with halt and closing all the open prolog windows , then open an other complete new instance of Prolog and run the predicate the update goes well. I have a feeling that there is some connection reference to the MySQL DB in Prolog database. Is there any way to clear the database in prolog so that I can run the same predicate without closing any existing prolog windows? Any ideas appreciated. Thanks.

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  • Using a Visual Sourcesafe 2005 database with VB6 still launches VSS 6.0d

    - by John Galt
    I know all versions of VSS have many horror stories and I feel I will escape to a better source control mechanism someday but in the short term I am just trying to do a little cleanup and would like your advice on this issue: Objective - consolidate old VB6 source code in a "new" VSS 2005 database (currently all these old projects are checked in to an "old" VSS 6.0d database); eventually, eliminate the "old" VSS. Progress so far - The new VSS 2005 database now contains a mixture of projects. Some are using Visual Studio 2008, some use Vstudio 2005, and the more recently added ones are the above mentioned VB6 projects. Individually all these projects and "solutions" come up OK, I can check in - check out, launch SourceSafe, view differences, etc. But all the VB6 projects now in a VSS 2005 database launch VSS 6.0d when asked, rather than VSS 2005. Is this normal and just something to cope with until I get to some better nonVSS approach? Or can VB6 be re-configured someway to launch VSS 2005 when I click Tools-SourceSafe-Run SourceSafe? I seem to recall VSS 6.0d got "integrated" into VB6 by way of the "Add-In Manager". At this point, the development PC with VB6 installed has both VSS 2005 and VSS 6.0d clients installed.

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  • Problem with XML encoding of database contents with Latin characters

    - by user89691
    I have an ASP Access database that contains strings in various European languages. The database was populated prior by agents in the respective countries. It contains entries with accented etc characters as you would expect. If I open the database with MS Access these characters show up fine. For example the the German equivalent of "Open" shows as "Öffnen" (hopefully you can see an "O" with 2 dots above it!). I have ASP code that reads the database and returns records in XML. The text is passed to XMLEncode to construct the XML, but that only seems to deal with the 5 specials like "<", "&", etc. If I dump the XML the accented characters are unchanged. <English>Open</English> <German>Öffnen</German> If I look at the raw packets with Wireshark I see that the "Ö" byte is hex D6, which appears to be it's decimal Unicode and ISO 8859-1 value. The problem starts when I try to parse the XML in client-side JS. I get: "An invalid character was found in text content" from IE. FF and Chrome happily accept the XML without hiccup but the browser shows the "Ö" character as a diamond with a question mark inside. http://www.validome.org/xml/validate/ reports "encoding error." http://www.w3schools.com/dom/dom_validate.asp thinks it is fine. The XML is UTF-8 encoded. What do I need to do to have IE accept my XML without complaint? What do I need to do to have browsers display the stuff correctly?

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  • Newbie database index question

    - by RenderIn
    I have a table with multiple indexes, several of which duplicate the same columns: Index 1 columns: X, B, C, D Index 2 columns: Y, B, C, D Index 3 columns: Z, B, C, D I'm not very knowledgeable on indexing in practice, so I'm wondering if somebody can explain why X, Y and Z were paired with these same columns. B is an effective date. C is a semi-unique key ID for this table for a specific effective date B. D is a sequence that identifies the priority of this record for the identifier C. Why not just create 6 indexes, one for each X, Y, Z, B, C, D? I want to add an index to another column T, but in some contexts I'll only be querying on T alone while in others I will also be specifying the B, C and D columns... so should I create just one index like above or should I create one for T and one for (T, B, C, D)? I've not had as much luck as expected when googling for comprehensive coverage of indexing. Any resources where I can get a through explanation and lots of examples of B-tree indexing?

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  • Database version is zero on initial install

    - by mahesh
    I have released an app (World Time) with initial database. Now i want to update the app with a database upgrade. I have put in the upgrade code in OnUpgrade() and checking for the newVersion. But it was not being called in my local testing... So i put in the debug statement to get the database version and it is zero . Any idea why it is not being versioned ? Following is the code to copy the database from my Assets folder ... InputStream myInput = myContext.getAssets().open(DB_NAME); // Path to the just created empty db String outFileName = DB_PATH + DB_NAME; //Open the empty db as the output stream OutputStream myOutput = new FileOutputStream(outFileName); //transfer bytes from the inputfile to the outputfile byte[] buffer = new byte[1024]; int length; while ((length = myInput.read(buffer))>0){ myOutput.write(buffer, 0, length); } //Close the streams myOutput.flush(); myOutput.close(); myInput.close(); -- Mahesh http://android.maheshdixit.com

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  • PHP database simulation

    - by Emdiesse
    I have a PHP script that works by calling items from a database based upon the time they were placed in there and it deletes them if they are older than 5 minutes. Basically, I want to now simulate what would happen if this database was being updated regularly. So I was considering sticking in some code that loads an XML file then goes through and parses that into the database based upon the time data located within a node of the xml data... but the problem there is I want it to continually loop through an enter this data so it'll never actually run the other processes So I was thinking of having another PHP script do that that could do this independantly of the php script that is going to display this data... In theory: I am looking to have a button that I can press and it will then run some php code to load up an XML file from a directory on my web server and then iterate though the data sending the data, to a database, based upon the time within a node in the PHP script and when the script was first called So back to my page that displayed the data... if I continually hit refresh it will contain different results each time because data is being added by the other process and this php script removes the older data when it is refreshed Any information on this? Is there a way I can silently, and safely, run a php script without it being loaded into a browser... like a thread!?

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  • NHibernate, legacy database, foreign keys that aren't

    - by Joe
    The project I'm working on has a legacy database with lots of information in it that's used to alter application behavior. Basically I'm stuck with something that I have to be super careful about changing. Onto my problem. In this database is a table and in this table is a column. This column contains integers and most of the pre-existing data have a value of zero for this column. The problem is that this column is in fact a foreign key reference to another entity, it was just never defined as such in the database schema. Now in my new code I defined my Fluent-NHibernate mapping to treat this column as a Reference so that I don't have to deal with entity id's directly in my code. This works fine until I come across an entity that has a value of 0 in this column. NHibernate thinks that a value of 0 is a valid reference. When my code tries to use that referenced object I get an ObjectNotFoundException as obviously there is no object in my database with an id of 0. How can I, either through mapping or some kind of convention (I'm using Fluent-nhibernate), get NHibernate to treat id's that are 0 the same as if it was NULL?

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  • Web page database query optimization

    - by morpheous
    I am putting together a web page which is quite 'expensive' in terms of database hits. I don't want to start optimizing at this stage - though with me trying to hit a deadline, I may end up not optimizing at all. Currently the page requires 18 (that's right eighteen) hits to the db. I am already using joins, and some of the queries are UNIONed to minimize the trips to the db. My local dev machine can handle this (page is not slow) however, I feel if I release this into the wild, the number of queries will quickly overwhelm my database (MySQL). I could always use memcache or something similar, but I would much rather continue with my other dev work that needs to be completed before the deadline - at least retrieving the page works - its simply a matter of optimization now (if required). My question therefore is - is 18 db queries for a single page retrieval completely outrageous - (i.e. I should put everything on hold and optimize the hell of the retrieval logic), or shall I continue as normal, meet the deadline and release on schedule and see what happens? [Edit] Just to clarify, I have already done the 'obvious' things like using (single and composite) indexes for fields used in the queries. What I haven't yet done is to run a query analyzer to see if my indexes etc are optimal.

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  • Android ExpandableListView From Database

    - by SterAllures
    I want to create a two level ExpandableListView from a local database. The group level I want to get the names from the database Category table category_id | name ------------------- 1 | NameOfCategory the children level I want to get the names from the List table list_id | name | foreign_category_id -------------------------------- 1 | Listname | 1 I've got a method in DatabaseDAO to get all the values from the table public List<Category> getAllCategories() { database = dbHelper.getReadableDatabase(); List<Category> categories = new ArrayList<Category>(); Cursor cursor = database.query(SQLiteHelper.TABLE_CATEGORY, null, null, null, null, null, null); cursor.moveToFirst(); while(!cursor.isAfterLast()) { Category category = cursorToCategory(cursor); categories.add(category); cursor.moveToNext(); } cursor.close(); return categories; } Now adding the names to the group level is easy I do it the following way: ArrayList<String> groups; for(Category c : databaseDao.getAllCategories()) { groups.add(c.getName()); } Now I want to add the children to the ExpandableListView in the following array ArrayList<ArrayList<ArrayList<String>>> children;. How do I get the children under the correct group name? I think it has to do somenthing with groups.indexOf() but in the list table I only have a foreign category_id and not the actual name.

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