Search Results

Search found 30375 results on 1215 pages for 'database smell'.

Page 665/1215 | < Previous Page | 661 662 663 664 665 666 667 668 669 670 671 672  | Next Page >

  • C# Interface Method calls from a controller

    - by ArjaaAine
    I was just working on some application architecture and this may sound like a stupid question but please explain to me how the following works: Interface: public interface IMatterDAL { IEnumerable<Matter> GetMattersByCode(string input); IEnumerable<Matter> GetMattersBySearch(string input); } Class: public class MatterDAL : IMatterDAL { private readonly Database _db; public MatterDAL(Database db) { _db = db; LoadAll(); //Private Method } public virtual IEnumerable<Matter> GetMattersBySearch(string input) { //CODE return result; } public virtual IEnumerable<Matter> GetMattersByCode(string input) { //CODE return results; } Controller: public class MatterController : ApiController { private readonly IMatterDAL _publishedData; public MatterController(IMatterDAL publishedData) { _publishedData = publishedData; } [ValidateInput(false)] public JsonResult SearchByCode(string id) { var searchText = id; //better name for this var results = _publishedData.GetMattersBySearch(searchText).Select( matter => new { MatterCode = matter.Code, MatterName = matter.Name, matter.ClientCode, matter.ClientName }); return Json(results); } This works, when I call my controller method from jquery and step into it, the call to the _publishedData method, goes into the class MatterDAL. I want to know how does my controller know to go to the MatterDAL implementation of the Interface IMatterDAL. What if I have another class called MatterDAL2 which is based on the interface. How will my controller know then to call the right method? I am sorry if this is a stupid question, this is baffling me.

    Read the article

  • can I put my sqlite connection and cursor in a function?

    - by steini
    I was thinking I'd try to make my sqlite db connection a function instead of copy/pasting the ~6 lines needed to connect and execute a query all over the place. I'd like to make it versatile so I can use the same function for create/select/insert/etc... Below is what I have tried. The 'INSERT' and 'CREATE TABLE' queries are working, but if I do a 'SELECT' query, how can I work with the values it fetches outside of the function? Usually I'd like to print the values it fetches and also do other things with them. When I do it like below I get an error Traceback (most recent call last): File "C:\Users\steini\Desktop\py\database\test3.py", line 15, in <module> for row in connection('testdb45.db', "select * from users"): ProgrammingError: Cannot operate on a closed database. So I guess the connection needs to be open so I can get the values from the cursor, but I need to close it so the file isn't always locked. Here's my testing code: import sqlite3 def connection (db, arg): conn = sqlite3.connect(db) conn.execute('pragma foreign_keys = on') cur = conn.cursor() cur.execute(arg) conn.commit() conn.close() return cur connection('testdb.db', "create table users ('user', 'email')") connection('testdb.db', "insert into users ('user', 'email') values ('joey', 'foo@bar')") for row in connection('testdb45.db', "select * from users"): print row How can I make this work?

    Read the article

  • Any suggestions to improve my PDO connection class?

    - by Scarface
    Hey guys I am pretty new to pdo so I basically just put together a simple connection class using information out of the introductory book I was reading but is this connection efficient? If anyone has any informative suggestions, I would really appreciate it. class PDOConnectionFactory{ public $con = null; // swich database? public $dbType = "mysql"; // connection parameters public $host = "localhost"; public $user = "user"; public $senha = "password"; public $db = "database"; public $persistent = false; // new PDOConnectionFactory( true ) <--- persistent connection // new PDOConnectionFactory() <--- no persistent connection public function PDOConnectionFactory( $persistent=false ){ // it verifies the persistence of the connection if( $persistent != false){ $this->persistent = true; } } public function getConnection(){ try{ $this->con = new PDO($this->dbType.":host=".$this->host.";dbname=".$this->db, $this->user, $this->senha, array( PDO::ATTR_PERSISTENT => $this->persistent ) ); // carried through successfully, it returns connected return $this->con; // in case that an error occurs, it returns the error; }catch ( PDOException $ex ){ echo "We are currently experiencing technical difficulties. We have a bunch of monkies working really hard to fix the problem. Check back soon: ".$ex->getMessage(); } } // close connection public function Close(){ if( $this->con != null ) $this->con = null; } }

    Read the article

  • Is something along the lines of nested memoization needed here?

    - by Daniel
    System.Transactions notoriously escalates transactions involving multiple connections to the same database to the DTC. The module and helper class, ConnectionContext, below are meant to prevent this by ensuring multiple connection requests for the same database return the same connection object. This is, in some sense, memoization, although there are multiple things being memoized and the second is dependent on the first. Is there some way to hide the synchronization and/or mutable state (perhaps using memoization) in this module, or perhaps rewrite it in a more functional style? (It may be worth nothing that there's no locking when getting the connection by connection string because Transaction.Current is ThreadStatic.) type ConnectionContext(connection:IDbConnection, ownsConnection) = member x.Connection = connection member x.OwnsConnection = ownsConnection interface IDisposable with member x.Dispose() = if ownsConnection then connection.Dispose() module ConnectionManager = let private _connections = new Dictionary<string, Dictionary<string, IDbConnection>>() let private getTid (t:Transaction) = t.TransactionInformation.LocalIdentifier let private removeConnection tid = let cl = _connections.[tid] for (KeyValue(_, con)) in cl do con.Close() lock _connections (fun () -> _connections.Remove(tid) |> ignore) let getConnection connectionString (openConnection:(unit -> IDbConnection)) = match Transaction.Current with | null -> new ConnectionContext(openConnection(), true) | current -> let tid = getTid current // get connections for the current transaction let connections = match _connections.TryGetValue(tid) with | true, cl -> cl | false, _ -> let cl = Dictionary<_,_>() lock _connections (fun () -> _connections.Add(tid, cl)) cl // find connection for this connection string let connection = match connections.TryGetValue(connectionString) with | true, con -> con | false, _ -> let initial = (connections.Count = 0) let con = openConnection() connections.Add(connectionString, con) // if this is the first connection for this transaction, register connections for cleanup if initial then current.TransactionCompleted.Add (fun args -> let id = getTid args.Transaction removeConnection id) con new ConnectionContext(connection, false)

    Read the article

  • Running Cargo From Maven antrun Plugin

    - by Frank
    I have a maven (multi-module) project creating some WAR and EAR files for JBoss AS 7.1.x. For one purpose, I need to deploy one generated EAR file of one module to a fresh JBoss instance and run it, call some REST web service calls against it and stop JBoss. Then I need to package the results of these calls that were written to the database. Currently, I am trying to use CARGO and the maven ant run plugin to perform this task. Unfortunately, I cannot get the three (maven, ant run and CARGO) to play together. I don't have the uberjar that is used in the ant examples of cargo. How can I configure the ant run task so that the cargo ant task can create, start, deploy my JBoss? Ideally the one unpacked and configured by the cargo-maven2-plugin in another phase? Or, is there a better way to achieve my goal of creating the database? I cannot really use the integration-test phase, as it is executed after the package phase. So, I plan to do it all in compile phase using antrun.

    Read the article

  • Entity framework self referencing loop detected

    - by Lyd0n
    I have a strange error. I'm experimenting with a .NET 4.5 Web API, Entity Framework and MS SQL Server. I've already created the database and set up the correct primary and foreign keys and relationships. I've created a .edmx model and imported two tables: Employee and Department. A department can have many employees and this relationship exists. I created a new controller called EmployeeController using the scaffolding options to create an API controller with read/write actions using Entity Framework. In the wizard, selected Employee as the model and the correct entity for the data context. The method that is created looks like this: // GET api/Employee public IEnumerable<Employee> GetEmployees() { var employees = db.Employees.Include(e => e.Department); return employees.AsEnumerable(); } When I call my API via /api/Employee, I get this error: ...The 'ObjectContent`1' type failed to serialize the response body for content type 'application/json; ...System.InvalidOperationException","StackTrace":null,"InnerException":{"Message":"An error has occurred.","ExceptionMessage":"Self referencing loop detected with type 'System.Data.Entity.DynamicProxies.Employee_5D80AD978BC68A1D8BD675852F94E8B550F4CB150ADB8649E8998B7F95422552'. Path '[0].Department.Employees'.","ExceptionType":"Newtonsoft.Json.JsonSerializationException","StackTrace":" ... Why is it self referencing [0].Department.Employees? That doesn't make a whole lot of sense. I would expect this to happen if I had circular referencing in my database but this is a very simple example. What could be going wrong?

    Read the article

  • ORDER BY in a Sql Server 2008 view

    - by eidylon
    Hi all... we have a view in our database which has an ORDER BY in it. Now, I realize views generally don't order, because different people may use it for different things, and want it differently ordered. This view however is used for a VERY SPECIFIC use-case which demands a certain order. (It is team standings for a soccer league.) The database is Sql Server 2008 Express, v.10.0.1763.0 on a Windows Server 2003 R2 box. The view is defined as such: CREATE VIEW season.CurrentStandingsOrdered AS SELECT TOP 100 PERCENT *, season.GetRanking(TEAMID) RANKING FROM season.CurrentStandings ORDER BY GENDER, TEAMYEAR, CODE, POINTS DESC, FORFEITS, GOALS_AGAINST, GOALS_FOR DESC, DIFFERENTIAL, RANKING It returns: GENDER, TEAMYEAR, CODE, TEAMID, CLUB, NAME, WINS, LOSSES, TIES, GOALS_FOR, GOALS_AGAINST, DIFFERENTIAL, POINTS, FORFEITS, RANKING Now, when I run a SELECT against the view, it orders the results by GENDER, TEAMYEAR, CODE, TEAMID. Notice that it is ordering by TEAMID instead of POINTS as the order by clause specifies. However, if I copy the SQL statement and run it exactly as is in a new query window, it orders correctly as specified by the ORDER BY clause.

    Read the article

  • How can I introduce a regex action to match the first element in a Catalyst URI ?

    - by RET
    Background: I'm using a CRUD framework in Catalyst that auto-generates forms and lists for all tables in a given database. For example: /admin/list/person or /admin/add/person or /admin/edit/person/3 all dynamically generate pages or forms as appropriate for the table 'person'. (In other words, Admin.pm has actions edit, list, add, delete and so on that expect a table argument and possibly a row-identifying argument.) Question: In the particular application I'm building, the database will be used by multiple customers, so I want to introduce a URI scheme where the first element is the customer's identifier, followed by the administrative action/table etc: /cust1/admin/list/person /cust2/admin/add/person /cust2/admin/edit/person/3 This is for "branding" purposes, and also to ensure that bookmarks or URLs passed from one user to another do the expected thing. But I'm having a lot of trouble getting this to work. I would prefer not to have to modify the subs in the existing framework, so I've been trying variations on the following: sub customer : Regex('^(\w+)/(admin)$') { my ($self, $c, @args) = @_; #validation of captured arg snipped.. my $path = join('/', 'admin', @args); $c->request->path($path); $c->dispatcher->prepare_action($c); $c->forward($c->action, $c->req->args); } But it just will not behave. I've used regex matching actions many times, but putting one in the very first 'barrel' of a URI seems unusually traumatic. Any suggestions gratefully received.

    Read the article

  • Read varbinary data in java

    - by masoud farahani
    I made a Java application which reads some files from SQL server. Those files are saved to a varbinary(MAX) field in SQL Server by a third party web service. My problem is that when I want to read those files with my Java application, those binary data show different content in the Java application. In fact, I read data byte by byte and I figured out that some bytes did not show the real values which were saved in the database. I found out what the problem is, but I couldn’t find a solution yet. I found out that in the web service every varbinary data is saved to database as byte data (in .Net each byte takes 0 to 255). But, when I want to read the binary data in Java, it takes different values and cause an exception with some values, because in Java a byte value takes -127 to 127. In my Java application I want to write those data to a file by OutputStream.write(byte[]) method. How can I solve this problem? I think that I have to find a way to convert c# byte[] to a Java byte[] (or binary data), but how can I do that?

    Read the article

  • Does new JUnit 4.8 @Category render test suites almost obsolete?

    - by grigory
    Given question 'How to run all tests belonging to a certain Category?' and the answer would the following approach be better for test organization? define master test suite that contains all tests (e.g. using ClasspathSuite) design sufficient set of JUnit categories (sufficient means that every desirable collection of sets is identifiable using one or more categories) define targeted test suites based on master test suite and set of categories For example: identify categories for speed (slow, fast), dependencies (mock, database, integration), function (), domain ( demand that each test is properly qualified (tagged) with relevant set of categories. create master test suite using ClasspathSuite (all tests found in classpath) create targeted suites by qualifying master test suite with categories, e.g. mock test suite, fast database test suite, slow integration for domain X test suite, etc. My question is more like soliciting approval rate for such approach vs. classic test suite approach. One unbeatable benefit is that every new test is immediately contained by relevant suites with no suite maintenance. One concern is proper categorization of each test.

    Read the article

  • How to optimize a postgreSQL server for a "write once, read many"-type infrastructure ?

    - by mhu
    Greetings, I am working on a piece of software that logs entries (and related tagging) in a PostgreSQL database for storage and retrieval. We never update any data once it has been inserted; we might remove it when the entry gets too old, but this is done at most once a day. Stored entries can be retrieved by users. The insertion of new entries can happen rather fast and regularly, thus the database will commonly hold several millions elements. The tables used are pretty simple : one table for ids, raw content and insertion date; and one table storing tags and their values associated to an id. User search mostly concern tags values, so SELECTs usually consist of JOIN queries on ids on the two tables. To sum it up : 2 tables Lots of INSERT no UPDATE some DELETE, once a day at most some user-generated SELECT with JOIN huge data set What would an optimal server configuration (software and hardware, I assume for example that RAID10 could help) be for my PostgreSQL server, given these requirements ? By optimal, I mean one that allows SELECT queries taking a reasonably little amount of time. I can provide more information about the current setup (like tables, indexes ...) if needed.

    Read the article

  • codeigniter mulitple LIKE db query using associative array- but all from the same column name...?

    - by Inigo
    Hi, I'm trying to query my database using codeigniter's active record class. I have a number of blog posts stored in a table. The query is for a search function, which will pull out all the posts that have certain categories assigned to them. So the 'category' column of the table will have a list of all the categories for that post in no particular order, separated by commas, like so: Politics,History,Sociology.. etc. If a user selects, say, Politics and History, The titles of all the posts that have BOTH these categories should be returned. Right? So, the list of categories queried will be the array $cats. I thought this would work- foreach ($cats as $cat){ $this->db->like('categories',$cat); } By Producing this- $this-db-like('categories','Politics'); $this-db-like('categories','History'); (Which would produce- 'WHERE categories LIKE '%Politics%' AND categories LIKE '%History%') But it doesn't work, it seems to only produce the first statement. The problem I guess is that the column name is the same for each of the chained queries. There doesn't seem to be anything in the CI user guide about this (http://codeigniter.com/user_guide/database/active_record.html) as they seem to assume that each chained statement is going to be for a different column name. Does anyone know how I could do this? Thanks! edit- Of course it is not possible to use an associative array in one statement as it would have to contain duplicate keys- in this case every key would have to be 'categories'...

    Read the article

  • MVVM: Do I need Inheritance with ViewModels A + B ?

    - by Lisa
    Hello guys my first post on SO because EE sucks in the meantime ;P I am using wpf and mvvm in my desktop application. Scenario: I have a calendar with week A and week B which are rotating by every X week depending on the user settings. But the UserControl "week B" is only visible when the user sets the option "rotating weeks"... The UserControl with week A has a DataGrid and for week B I want to use the same UserControl of course. What I want to achieve is that all data entered/choosen by the user in the Week A is saved/backed by a ViewModel A and Model C. When the user wants a rotating weekly calendar plan I need also a ViewModel B and again Model C. The reason why I need to know what data entered by the user belongs to week A or week B is because I have to write the entered data in a certain order into the database = db.Write(weekA),db.Write(weekB),db.Write(weekA),etc... I am unsure how a solution could look like... What would you do to identify a ViewModel A or B so you know the order of how to write the data in the proper order into database? Any other suggestions are also welcome of course, maybe I think in the wrong direction its late here :) I am new to mvvm so please be patient.

    Read the article

  • [MFC] What is the reciprocal of CComboBox.GetItemData?

    - by Hamish Grubijan
    Instead of associating objects with Combo Box items, I associate long ids representing choices. They come from a database, so it seems natural to do so anyway. Now, I persist the id and not the index of the user's selection, so that the choice is remembered across sessions. If id no longer exists in database - no big deal. The choice will be messed up once. If db does not change, however, then it would be a great success ;) Here is how I get the id : chosenSomethingIndex = cmbSomething.GetCurSel(); lastSomethingId = cmbSomething.GetItemData(chosenSomethingIndex); How do I reverse this? When I load the stored value for user's last choice, I need to convert that id into an index. I can do: cmbSomething.SetCurSel(chosenSomethingIndex); However, how can I attempt (it might not exist) to get an index once I have an id? I am looking for a reciprocal function to GetItemData I am using VS2008, probably latest version of MFC, whatever that is. Thank you.

    Read the article

  • Forms authentication: how do you store username password in web.config?

    - by Nick G
    I'm used to using Forms Authentication with a database, but I'm writing a little internal utility and the app doesn't have a database so I want to store the username and password in web.config. However for some reason, forms authentication is still trying to access SQL Server and I can't see how to stop it doing this and pick up the credentials from web.config. What am I doing wrong? I just get the error "Failed to generate a user instance of SQL Server due to a failure in impersonating the client. The connection will be closed." Here are the relevant sections of my web.config: <configuration> <system.web> <authentication mode="Forms"> <forms loginUrl="~/Login.aspx" timeout="60" name=".LoginCookie" path="/" > <credentials passwordFormat="Clear"> <user name="user1" password="[pass]" /> <user name="user2" password="[pass]" /> </credentials> </forms> </authentication> <authorization> <deny users="?" /> </authorization> </system.web> </configuration>

    Read the article

  • Not getting key value from Identity column back after inserting new row with SubSonic ActiveRecord

    - by mikedevenney
    I'm sure I'm missing the obvious answer here, but could use a hand. I'm new to SubSonic and using version 3. I've got myself to the point of being able to query and insert, but I'm stuck with how I would get the value of the identity column back after my insert. I saw another post that mentioned Linq Templates. I'm not using those (at least I don't think I am...?) TIA ... UPDATE ... So I've been debugging through my code watching how the SubSonic code works and I found where the indentity column is being ignored. I use int as the datatype for my ID columns in the database and set them as identity. Since int is a non-nullable data type in c# the logical test in the Add method (public void Add(IDataProvider provider)) that checks if there is a value in the key column by doing a (key==null) could be the issue. The code that gets the new value for the identity field is in the 'true path', since an int can't be null and I use ints as my identity column data types this test will never pass. The ID field for my object has a 0 in it that I didn't put there. I assume it's set during the initialization of the object. Am I off base here? Is the answer to change my data types in the database? Another question (more a curiosity). I noticed that some of the properties in the generated classes are declared with a ? after the datatype. I'm not familiar with this declaration construct... what gives? There are some declared as an int (non key fields) and others that are declared as int? (key fields). Does this have something to do with how they're treated at initialization? Any help is appreciated! --BUMP--

    Read the article

  • Preventing ActiveRecord save() on an instance

    - by Craig Walker
    I have an ActiveRecord model object Foo; it represents a standard database row. I want to be able to display modified versions of instances of this object. I'd like to reuse the class itself, as it already has all the hooks & aspects I'll need. (For example: I already have a view that displays the appropriate attributes). Basically I want to clone the model instance, modify some of its properties, and feed it back to the caller (view, test, etc). I do not want these attribute modifications getting back into the database. However, I do want to include the id attribute in the cloned version, as it makes dealing with the route-helpers much easier. Thus, I plan on calling ActiveRecord::Base.clone(), manually setting the ID of the cloned instance, and then making the appropriate attribute changes to the new instance. This has me worried though; one save() on the modified instance and my original data will get clobbered. So, I'm looking to lock down the new instance so that it won't hurt anything else. I'm already planning on calling freeze() (on the understanding that this prevents further modification to the object, though the documentation isn't terribly clear). However, I don't see any obvious way to prevent a save(). What would be the best approach to achieving this?

    Read the article

  • Function returning a class containing a function returning a class

    - by Scott
    I'm working on an object-oriented Excel add-in to retrieve information from our ERP system's database. Here is an example of a function call: itemDescription = Macola.Item("12345").Description Macola is an instance of a class which takes care of database access. Item() is a function of the Macola class which returns an instance of an ItemMaster class. Description() is a function of the ItemMaster class. This is all working correctly. Items can be be stored in more than one location, so my next step is to do this: quantityOnHand = Macola.Item("12345").Location("A1").QuantityOnHand Location() is a function of the ItemMaster class which returns an instance of the ItemLocation class (well, in theory anyway). QuantityOnHand() is a function of the ItemLocation class. But for some reason, the ItemLocation class is not even being intialized. Public Function Location(inventoryLocation As String) As ItemLocation Set Location = New ItemLocation Location.Item = item_no Location.Code = inventoryLocation End Function In the above sample, the variable item_no is a member variable of the ItemMaster class. Oddly enough, I can successfully instantiate the ItemLocation class outside of the ItemMaster class in a non-class module. Dim test As New ItemLocation test.Item = "12345" test.Code = "A1" quantityOnHand = test.QuantityOnHand Is there some way to make this work the way I want? I'm trying to keep the API as simple as possible. So that it only takes one line of code to retrieve a value.

    Read the article

  • Excel - Best Way to Connect With Access Data

    - by gamerzfuse
    Hello there, Here is the situation we have: a) I have an Access database / application that records a significant amount of data. Significant fields would be hours, # of sales, # of unreturned calls, etc b) I have an Excel document that connects to the Access database and pulls data in to visualize it As it stands now, the Excel file has a Refresh button that loads new data. The data is loaded into a large PivotTable. The main 'visual form' then uses VLOOKUP to get the results from the form, based on the related hours. This operation is slow (~10 seconds) and seems to be redundant and inefficient. Is there a better way to do this? I am willing to go just about any route - just need directions. Thanks in advance! Update: I have confirmed (due to helpful comments/responses) that the problem is with the data loading itself. removing all the VLOOKUPs only took a second or two out of the load time. So, the questions stands as how I can rapidly and reliably get the data without so much time involvement (it loads around 3000 records into the PivotTables).

    Read the article

  • how to handle empty selection in a jface bound combobox?

    - by guido
    I am developing a search dialog in my eclipse-rcp application. In the search dialog I have a combobox as follows: comboImp = new CCombo(grpColSpet, SWT.BORDER | SWT.READ_ONLY); comboImp.setBounds(556, 46, 184, 27); comboImpViewer = new ComboViewer(comboImp); comboImpViewer.setContentProvider(new ArrayContentProvider()); comboImpViewer.setInput(ImpContentProvider.getInstance().getImps()); comboImpViewer.setLabelProvider(new LabelProvider() { @Override public String getText(Object element) { return ((Imp)element).getImpName(); } }); Imp is a database entity, ManyToOne to the main entity which is searched, and ImpContentProvider is the model class which speaks to embedded sqlite database via jpa/hibernate. This combobox is supposed to contain all instances of Imp, but to also let empty selection; it's value is bound to a service bean as follows: IObservableValue comboImpSelectionObserveWidget = ViewersObservables.observeSingleSelection(comboImpViewer); IObservableValue filterByImpObserveValue = BeansObservables.observeValue(searchPrep, "imp"); bindingContext.bindValue(comboImpSelectionObserveWidget, filterByImpObserveValue , null, null); As soon as the user clicks on the combo, a selection (first element) is made: I can see the call to a selectionlistener i added on the viewer. My question is: after a selection has been made, how do I let the user change his mind and have an empty selection in the combobox? should I add a "fake" empty instance of Imp to the List returned by the ImpContentProvider? or should I implement an alternative to ArrayContentProvider? and one additional related question is: why calling deselectAll() and clearSelection() on the combo does NOT set a null value to the bound bean?

    Read the article

  • Updating iOS application content which include images

    - by azamsharp
    I am working on a Vegetable gardening application. Apart from the vegetable name and description I also have vegetable image. Currently, I have all the images in the Supported Files folder in the Xcode project. But later on I want to update the application dynamically without having the user download a new version. When the user updates the application or downloads new data from the server that data will include the images. Can I store those images in the supporting file folder or somewhere where they can be references by just the name. RELATED QUESTION: I will also allow the user to take pictures of their vegetables and then write notes about the vegetables like "just planted", "about to harvest" etc. What is the recommended approach for storing pictures/photos. I can always store them in the user's photo library and then store the reference in the local database and then fetch and display the picture using the reference. The problem with that approach might be that if the user accidentally deletes the picture from the library then it will no longer be displayed in my application. The only way I see if to store the picture in the app local database as a BLOB.

    Read the article

  • PHP Check slave status without mysql_connect timeout issues

    - by Jonathon
    I have a web-app that has a master mysql db and four slave dbs. I want to handle all (or almost all) read-only (SELECT) queries from the slaves. Our load-balancer sends the user to one of the slave machines automatically, since they are also running Apache/PHP and serving webpages. I am using an include file to setup the connection to the databases, such as: //for master server (i.e. - UPDATE/INSERT/DELETE statements) $Host = "10.0.0.x"; $User = "xx"; $Password = "xx"; $Link = mysql_connect( $Host, $User, $Password ); if( !$Link ) ) { die( "Master database is currently unavailable. Please try again later." ); } //this connection can be used for READ-ONLY (i.e. - SELECT statements) on the localhost $Host_Local = "localhost"; $User_Local = "xx"; $Password_Local = "xx"; $Link_Local = mysql_connect( $Host_Local, $User_Local, $Password_Local ); //fail back to master if slave db is down if( !$Link_Local ) ) { $Link_Local = mysql_connect( $Host, $User, $Password ); } I then use $Link for all update queries and $Link_Local as the connection for SELECT statements. Everything works fine until the slave server database goes down. If the local db is down, the $Link_Local = mysql_connect() call takes at least 30 seconds before it gives up on trying to connect to the localhost and returns back to the script. This causes a huge backlog of page serves and basically shuts down the system (due to the extremely slow response time). Does anyone know of a better way to handle connections to slave servers via PHP? Or, is there some kind of timeout function that could be used to stop the mysql_connect call after 2-3 seconds? Thanks for the help. I searched the other mysql_connect threads, but didn't see any that addressed this issue.

    Read the article

  • How to use db4o IObjectContainer in a web application ? (Container lifetime ?)

    - by driis
    I am evaluating db4o for persistence for a ASP .NET MVC project. I am wondering how I should use the IObjectContainer in a web context with regards to object lifetime. As I see it, I can do one of the following: Create the IObjectContainer at application startup and keep the same instance for the entire application lifetime. Create one IObjectContainer per request. Start a server, and get a client IObjectContainer for each database interaction. What are the implications of these options, in terms of performance and concurrency ? Since the database is locked when an IObjectContainer is opened, I am pretty sure that option 2) would get me some problems with concurrency - would this also be the case for option 1 ? As I understand it, if I retrieve an object from an IObjectContainer, it must be saved by the same IObjectContainer instance - in order for db4o to identify it as being the same object. Therefore, If I choose option 3), I would have to retrieve the original object, make the necessary changes (copy data from a modified object), and then store it using the same IObjectContainer. Is this true ?

    Read the article

  • GridView ObjectDataSource LINQ Paging and Sorting using multiple table query.

    - by user367426
    I am trying to create a pageing and sorting object data source that before execution returns all results, then sorts on these results before filtering and then using the take and skip methods with the aim of retrieving just a subset of results from the database (saving on database traffic). this is based on the following article: http://www.singingeels.com/Blogs/Nullable/2008/03/26/Dynamic_LINQ_OrderBy_using_String_Names.aspx Now I have managed to get this working even creating lambda expressions to reflect the sort expression returned from the grid even finding out the data type to sort for DateTime and Decimal. public static string GetReturnType<TInput>(string value) { var param = Expression.Parameter(typeof(TInput), "o"); Expression a = Expression.Property(param, "DisplayPriceType"); Expression b = Expression.Property(a, "Name"); Expression converted = Expression.Convert(Expression.Property(param, value), typeof(object)); Expression<Func<TInput, object>> mySortExpression = Expression.Lambda<Func<TInput, object>>(converted, param); UnaryExpression member = (UnaryExpression)mySortExpression.Body; return member.Operand.Type.FullName; } Now the problem I have is that many of the Queries return joined tables and I would like to sort on fields from the other tables. So when executing a query you can create a function that will assign the properties from other tables to properties created in the partial class. public static Account InitAccount(Account account) { account.CurrencyName = account.Currency.Name; account.PriceTypeName = account.DisplayPriceType.Name; return account; } So my question is, is there a way to assign the value from the joined table to the property of the current table partial class? i have tried using. from a in dc.Accounts where a.CompanyID == companyID && a.Archived == null select new { PriceTypeName = a.DisplayPriceType.Name}) but this seems to mess up my SortExpression. Any help on this would be much appreciated, I do understand that this is complex stuff.

    Read the article

  • Random problem connecting to MySQL

    - by CharlesLeaf
    Environment: RHEL 5 servers, MySQL 5.1.43, PHP 5.1.6 (using MySQLi). Currently only available within our internal VPN network. Servers ServerA: Webserver ServerB/C/D: Database server (1 master 2 slaves) The error (on ServerA) [Tue May 25 11:12:17 2010] [error] [client CLIENTIP] PHP Warning: mysqli::real_connect() [function.mysqli-real-connect]: (HY000/2003): Can't connect to MySQL server on 'ServerB' (4) in /home/**/Database.php on line 67, referer: [website] Problem description It appears that at completely random times, our website is unable to connect to one of the MySQL servers - usually the Master. Except for the forementioned error message, there is nothing to be found in any of the logs as far as I can see, and most of the times the connection is succesful and everything works as it should. It's just at completely random times, this error pops up. There's no firewall blocking any internal traffic, timeout value is 3 but it doesn't take 3 seconds before it fails to connect. With the default mysql client I can connect from ServerA to ServerB,C and D and haven't encountered a problem yet. Does anyone have a clue what I might be overlooking / could be the problem? Because I've run out of ideas myself.

    Read the article

< Previous Page | 661 662 663 664 665 666 667 668 669 670 671 672  | Next Page >