Search Results

Search found 10101 results on 405 pages for 'temporary tables'.

Page 358/405 | < Previous Page | 354 355 356 357 358 359 360 361 362 363 364 365  | Next Page >

  • using spring, hibernate and scala, is there a better way to load test data than dbunit?

    - by egervari
    Here are some things I really dislike about dbunit: 1) You cannot specify the exact ordering the inserts because dbunit likes to group your inserts by table name, and not by the order you define them in the XML file. This is a problem when you have records depending on other records in other tables, so you have to disable foreign key constraints during your tests... which actually sucks because these foreign key constraints will get fired in production while your tests won't be aware of them! 2) They seem hellbent on forcing you to use an xml namespace to define your xml... and I honestly can't be bothered to do this. I like the data.xml without any namespace. It works. But they are so hellbent on deprecating it. 3) Creating different xml files is hard on a per test basis, so it actually encourages creating data for your entire app. Unfortunately, this process is a little bloated too once the data grows in size and things get inter tangled. There has got to be a better way to split up your test data into chunks without having to copy/paste a lot of the test data across all of your tests. 4) Keeping track of id references in a big xml file is just impossible. If you have 130 domain classes, it just gets bewildering. This model simply does not scale. Is there something less bloated and better in the Spring/Hibernate space? db unit has worn out its welcome and I'm really looking for something better.

    Read the article

  • Howw to add new value with generic Repository if there are foreign keys (EF-4)?

    - by Phsika
    i try to write a kind of generic repository to add method. Everything is ok to add but I have table which is related with two tables with FOREIGN KEY.But Not working because of foreign key public class DomainRepository<TModel> : IDomainRepository<TModel> where TModel : class { #region IDomainRepository<T> Members private ObjectContext _context; private IObjectSet<TModel> _objectSet; public DomainRepository() { } public DomainRepository(ObjectContext context) { _context = context; _objectSet = _context.CreateObjectSet<TModel>(); } //do something..... public TModel Add<TModel>(TModel entity) where TModel : IEntityWithKey { EntityKey key; object originalItem; key = _context.CreateEntityKey(entity.GetType().Name, entity); _context.AddObject(key.EntitySetName, entity); _context.SaveChanges(); return entity; } //do something..... } Calling REPOSITORY: //insert-update-delete public partial class AddtoTables { public table3 Add(int TaskId, int RefAircraftsId) { using (DomainRepository<table3> repTask = new DomainRepository<table3>(new TaskEntities())) { return repTask.Add<table3>(new table3() { TaskId = TaskId, TaskRefAircraftsID = RefAircraftsId }); } } } How to add a new value if this table includes foreign key relation

    Read the article

  • Javascript can't find element by id?

    - by Bluemagica
    <html> <head> <title>Test javascript</title> <script type="text/javascript"> var e = document.getElementById("db_info"); e.innerHTML='Found you'; </script> </head> <body> <div id="content"> <div id="tables"> </div> <div id="db_info"> </div> </div> </body> </html> If I use alert(e); it turns up null.... and obviously I don't get any "found you" on screen. What am I doing wrong?

    Read the article

  • Constructor and Destructors in C++ work?

    - by Jack
    I am using gcc. Please tell me if I am wrong - Lets say I have two classes A & B class A { public: A(){cout<<"A constructor"<<endl;} ~A(){cout<<"A destructor"<<endl;} }; class B:public A { public: B(){cout<<"B constructor"<<endl;} ~B(){cout<<"B destructor"<<endl;} }; 1) The first line in B's constructor should be a call to A's constructor ( I assume compiler automatically inserts it). Also the last line in B's destructor will be a call to A's destructor (compiler does it again). Why was it built this way? 2) When I say A * a = new B(); compiler creates a new B object and checks to see if A is a base class of B and if it is it allows 'a' to point to the newly created object. I guess that is why we don't need any virtual constructors. ( with help from @Tyler McHenry , @Konrad Rudolph) 3) When I write delete a compiler sees that a is an object of type A so it calls A's destructor leading to a problem which is solved by making A's destructor virtual. As user - Little Bobby Tables pointed out to me all destructors have the same name destroy() in memory so we can implement virtual destructors and now the call is made to B's destructor and all is well in C++ land. Please comment.

    Read the article

  • Fix DB duplicate entries (MySQL bug)

    - by Silence
    I'm using MySQL 4.1. Some tables have duplicates entries that go against the constraints. When I try to group rows, MySQL doesn't recognise the rows as being similar. Example: Table A has a column "Name" with the Unique proprety. The table contains one row with the name 'Hach?' and one row with the same name but a square at the end instead of the '?' (which I can't reproduce in this textfield) A "Group by" on these 2 rows return 2 separate rows This cause several problems including the fact that I can't export and reimport the database. On reimporting an error mentions that a Insert has failed because it violates a constraint. In theory I could try to import, wait for the first error, fix the import script and the original DB, and repeat. In pratice, that would take forever. Is there a way to list all the anomalies or force the database to recheck constraints (and list all the values/rows that go against them) ? I can supply the .MYD file if it can be helpful.

    Read the article

  • Use of unassigned local variable 'xxx'

    - by Tomislav
    I'm writing a database importer from our competitors to ours database:) I have a code generator which create Methods form import to our database like public void Test_Import_Customer_1() // variables string conn; string sqlSelect; string sqlInsert; int extID; string name; string name2; DateTime date_inserted; sqlSelect="select id,name,date_inserted from table_competitors_1"; oledbreader reader = new GetOledbRader(sqlString,conn); while (reader.read()) { name=left((string)myreader["name"],50); //limitation of my field date_inserted=myreader["date_inserted"]; sqlInsert=string.Format("insert into table(name,name2,date_inserted)values '{0}', '{1}', {2})",name,name2,date_inserted); //here is the problem name2 "Use of unassigned local variable" ExecuteSQL(sqlInsert) } As different companies database has different fields i can not set value to each variable and there is a big number of tables to go one variable to next. like sqlSelect_Company_1 = "select name,date_inserted from table_1"; sqlSelect_Company_2 = "select name,name2 from table_2"; is there a way to override the typing of each variable one by one with default values?

    Read the article

  • Managing libraries and imports in a programming language

    - by sub
    I've created an interpreter for a stupid programming language in C++ and the whole core structure is finished (Tokenizer, Parser, Interpreter including Symbol tables, core functions, etc.). Now I have a problem with creating and managing the function libraries for this interpreter (I'll explain what I mean with that later) So currently my core function handler is horrible: // Simplified version myLangResult SystemFunction( name, argc, argv ) { if ( name == "print" ) { if( argc < 1 ) { Error('blah'); } cout << argv[ 0 ]; } else if ( name == "input" ) { if( argc < 1 ) { Error('blah'); } string res; getline( cin, res ); SetVariable( argv[ 0 ], res ); } else if ( name == "exit ) { exit( 0 ); } And now think of each else if being 10 times more complicated and there being 25 more system functions. Unmaintainable, feels horrible, is horrible. So I thought: How to create some sort of libraries that contain all the functions and if they are imported initialize themselves and add their functions to the symbol table of the running interpreter. However this is the point where I don't really know how to go on. What I wanted to achieve is that there is e.g.: an (extern?) string library for my language, e.g.: string, and it is imported from within a program in that language, example: import string myString = "abcde" print string.at( myString, 2 ) # output: c My problems: How to separate the function libs from the core interpreter and load them? How to get all their functions into a list and add it to the symbol table when needed? What I was thinking to do: At the start of the interpreter, as all libraries are compiled with it, every single function calls something like RegisterFunction( string namespace, myLangResult (*functionPtr) ); which adds itself to a list. When import X is then called from within the language, the list built with RegisterFunction is then added to the symbol table. Disadvantages that spring to mind: All libraries are directly in the interpreter core, size grows and it will definitely slow it down.

    Read the article

  • Specify Columntype in nhibernate

    - by Bipul
    I have a class CaptionItem public class CaptionItem { public virtual int SystemId { get; set; } public virtual int Version { get; set; } protected internal virtual IDictionary<string, string> CaptionValues {get; private set;} } I am using following code for nHibernate mapping Id(x => x.SystemId); Version(x => x.Version); Cache.ReadWrite().IncludeAll(); HasMany(x => x.CaptionValues) .KeyColumn("CaptionItem_Id") .AsMap<string>(idx => idx.Column("CaptionSet_Name"), elem => elem.Column("Text")) .Not.LazyLoad() .Cascade.Delete() .Table("CaptionValue") .Cache.ReadWrite().IncludeAll(); So in database two tables get created. One CaptionValue and other CaptionItem. In CaptionItem table has three columns 1. CaptionItem_Id int 2. Text nvarchar(255) 3. CaptionSet_Name nvarchar(255) Now, my question is how can I make the columnt type of Text to nvarchar(max)? Thanks in advance.

    Read the article

  • EFv1 mapping 1 to many Relationship to POCOs

    - by Scott
    I'm trying to work through a problem where I'm mapping EF Entities to POCO which serve as DTO. I have two tables within my database, say Products and Categories. A Product belongs to one category and one category may contain many Products. My EF entities are named efProduct and efCategory. Within each entity there is the proper Navigation Property between efProduct and efCategory. My Poco objects are simple public class Product { public string Name { get; set; } public int ID { get; set; } public double Price { get; set; } public Category ProductType { get; set; } } public class Category { public int ID { get; set; } public string Name { get; set; } public List<Product> products { get; set; } } To get a list of products I am able to do something like public IQueryable<Product> GetProducts() { return from p in ctx.Products select new Product { ID = p.ID, Name = p.Name, Price = p.Price ProductType = p.Category }; } However there is a type mismatch error because p.Category is of type efCategory. How can I resolve this? That is, how can I convert p.Category to type Category? I know in .NET EF has added support for POCO, but I'm forced to use .NET 3.5 SP1.

    Read the article

  • How do I make software that preserves database integrity and correctness? Please help, confused.

    - by user287745
    i have made an application project in vs 08 c#, sql server from vs 08. the database has like 20 tables and many fields in each have made an interface for adding deleting editting and retrieving data according to predefined needs of the users. now i have to 1) make to project in to a software which i can deliver to professor. that is he can just double click the icon and the software simply starts. no vs 08 needed to start the debugging 2) the database will be on one powerful computer (dual core latest everything win xp) and the user will access it from another computer connected using LAN i am able to change the connection string to the shared database using vs 08/ debugger whenever the server changes but how am i supposed to do that when its a software? 3)there will by many clients am i supposed to give the same software to every one, so they all can connect to the database, how will the integrity and correctness of the database be maintained? i mean the db.mdf file will be in a folder which will be shared with read and write access. so its not necessary that only one user will write at a time. so is there any coding for this or? please help me out here i am stuck do not know what to do i have no practical experience, would appreciate all the help thank you

    Read the article

  • Big-O for GPS data

    - by HH
    A non-critical GPS module use lists because it needs to be modifiable, new routes added, new distances calculated, continuos comparisons. Well so I thought but my team member wrote something I am very hard to get into. His pseudo code int k =0; a[][] <- create mapModuleNearbyDotList -array //CPU O(n) for(j = 1 to n) // O(nlog(m)) for(i =1 to n) for(k = 1 to n) if(dot is nearby) adj[i][j]=min(adj[i][j], adj[i][k] + adj[k][j]); His ideas transformations of lists to tables His worst case time complexity is O(n^3), where n is number of elements in his so-called table. Exception to the last point with Finite structure: O(mlog(n)) where n is number of vertices and m is an arbitrary constants Questions about his ideas why to waste resources to transform constantly-modified lists to table? Fast? only point where I to some extent agree but cannot understand the same upper limits n for each for-loops -- perhaps he supposed it circular why does the code take O(mlog(n)) to proceed in time as finite structure? The term finite may be wrong, explicit?

    Read the article

  • How do I Order on common attribute of two models in the DB?

    - by Will
    If i have two tables Books, CDs with corresponding models. I want to display to the user a list of books and CDs. I also want to be able to sort this list on common attributes (release date, genre, price, etc.). I also have basic filtering on the common attributes. The list will be large so I will be using pagination in manage the load. items = [] items << CD.all(:limit => 20, :page => params[:page], :order => "genre ASC") items << Book.all(:limit => 20, :page => params[:page], :order => "genre ASC") re_sort(items,"genre ASC") Right now I am doing two queries concatenating them and then sorting them. This is very inefficient. Also this breaks down when I use paging and filtering. If I am on page 2 of how do I know what page of each table individual table I am really on? There is no way to determine this information without getting all items from each table. I have though that if I create a new Class called items that has a one to one relationship with either a Book or CD and do something like Item.all(:limit => 20, :page => params[:page], :include => [:books, :cds], :order => "genre ASC") However this gives back an ambiguous error. So can only be refined as Item.all(:limit => 20, :page => params[:page], :include => [:books, :cds], :order => "books.genre ASC") And does not interleave the books and CDs in a way that I want. Any suggestions.

    Read the article

  • Do I need to write a trigger for such a simple constraint?

    - by Paul Hanbury
    I really had a hard time knowing what words to put into the title of my question, as I am not especially sure if there is a database pattern related to my problem. I will try to simplify matters as much as possible to get directly to the heart of the issue. Suppose I have some tables. The first one is a list of widget types: create table widget_types ( widget_type_id number(7,0) primary key, description varchar2(50) ); The next one contains icons: create table icons ( icon_id number(7,0) primary key, picture blob ); Even though the users get to select their preferred widget, there is a predefined subset of widgets that they can choose from for each widget type. create table icon_associations ( widget_type_id number(7,0) references widget_types, icon_id number(7,0) references icons, primary key (widget_type_id, icon_id) ); create table icon_prefs ( user_id number(7,0) references users, widget_type_id number(7,0), icon_id number(7,0), primary key (user_id, widget_type_id), foreign key (widget_type_id, icon_id) references icon_associations ); Pretty simple so far. Let us now assume that if we are displaying an icon to a user who has not set up his preferences, we choose one of the appropriate images associated with the current widget. I'd like to specify the preferred icon to display in such a case, and here's where I run into my problem: alter table icon_associations add ( is_preferred char(1) check( is_preferred in ('y','n') ) ) ; I do not see how I can enforce that for each widget_type there is one, and only one, row having is_preferred set to 'y'. I know that in MySQL, I am able to write a subquery in my check constraint to quickly resolve this issue. This is not possible with Oracle. Is my mistake that this column has no business being in the icon_associations table? If not where should it go? Is this a case where, in Oracle, the constraint can only be handled with a trigger? I ask only because I'd like to go the constraint route if at all possible. Thanks so much for your help, Paul

    Read the article

  • NHibernate will not insert a record

    - by Brian Beckham
    I have an application that is now 4+ years old that is exhibiting some odd behavior on our latest deployment. The application uses nHibernate for all inserts / updates / selects, etc. We are currently using .NET 2.0, and nHibernate 1.2 (I know, we need to upgrade) This deployment is on Windows 2008 Server x64, IIS 7.5 - what I have seen so far is that the application runs, but is unable to insert or update records in the DB - reads seem fine so far, but writes are a problem. SOME writes actually work, inserts into some small tables, but most never even make it to the DB. Using SQL Profiler, the insert / updates never make it to the server, and turning log4net up to DEBUG, and show_sql true - the select statements appear, but the insert / update statements never make it into the log at all, and never show up at the server. What's even more odd is that the application seems to be oblivious to this - the commandandclose runs without exception (open session in view with an httpmodule), the domain objects come back with uuid's generated, etc. but never get persisted. Certainly an upgrade is due, but I would hate to try it during a deployment, and without time to accurately test the app. Any ideas?

    Read the article

  • Help with create action in a different show page

    - by Andrew
    Hi, I'm a Rails newbie and want to do something but keep messing something up. I'd love some help. I have a simple app that has three tables. Users, Robots, and Recipients. Robots belong_to users and Recipients belong_to robots. On the robot show page, I want to be able to create recipients for that robot right within the robot show page. I have the following code in the robot show page which lists current recipients: <table> <% @robot.recipients.each do |recipient| %> <tr> <td><b><%=h recipient.chat_screen_name %></b> via <%=h recipient.protocol_name</td> <td><%= link_to 'Edit', edit_recipient_path(recipient) %>&nbsp;</td> <td><%= link_to 'Delete', recipient, :confirm => 'Are you sure?', :method => :delete %></td> </tr> <% end %> </table> What I'd like to do is have an empty field in which the user can add a new recipient, and have tried the following: I added this to the Robots Show view: <% form_for(@robot.recipient) do |f| %> Enter the screen name<br> <%= f.text_field :chat_screen_name %> <p> <%= f.submit 'Update' %> </p> <% end %> and then this to the Robot controller in the show action: @recipient = Recipient.new @recipients = Recipient.all Alas, I'm still getting a NoMethod error that says: "undefined method `recipient' for #" I'm not sure what I'm missing. Any help would be greatly appreciated. Thank you.

    Read the article

  • Why does the WCF 3.5 REST Starter Kit do this?

    - by Brandon
    I am setting up a REST endpoint that looks like the following: [WebInvoke(Method = "POST", UriTemplate = "?format=json", BodyStyle = WebMessageBodyStyle.WrappedRequest, ResponseFormat = WebMessageFormat.Json)] and [WebInvoke(Method = "DELETE", UriTemplate = "?token={token}&format=json", ResponseFormat = WebMessageFormat.Json)] The above throws the following error: UriTemplateTable does not support '?format=json' and '?token={token}&format=json' since they are not equivalent, but cannot be disambiguated because they have equivalent paths and the same common literal values for the query string. See the documentation for UriTemplateTable for more detail. I am not an expert at WCF, but I would imagine that it should map first by the HTTP Method and then by the URI Template. It appears to be backwards. If both of my URI templates are: ?token={token}&format=json This works because they are equivalent and it then appears to look at the HTTP Method where one is POST and the other is DELETE. Is REST supposed to work this way? Why are the URI Template Tables not being sorted first by HTTP Method and then by URI Template? This can cause some serious frustrations when 1 HTTP Method requires a parameter and another does not, or if I want to do optional parameters (e.g. if the 'format' parameter is not passed, default to XML).

    Read the article

  • can this problem be solved with a single SQL query?

    - by PierrOz
    I have the two following tables (with some sample datas) LOGS: ID | SETID | DATE ======================== 1 | 1 | 2010-02-25 2 | 2 | 2010-02-25 3 | 1 | 2010-02-26 4 | 2 | 2010-02-26 5 | 1 | 2010-02-27 6 | 2 | 2010-02-27 7 | 1 | 2010-02-28 8 | 2 | 2010-02-28 9 | 1 | 2010-03-01 STATS: ID | OBJECTID | FREQUENCY | STARTID | ENDID ============================================= 1 | 1 | 0.5 | 1 | 5 2 | 2 | 0.6 | 1 | 5 3 | 3 | 0.02 | 1 | 5 4 | 4 | 0.6 | 2 | 6 5 | 5 | 0.6 | 2 | 6 6 | 6 | 0.4 | 2 | 6 7 | 1 | 0.35 | 3 | 7 8 | 2 | 0.6 | 3 | 7 9 | 3 | 0.03 | 3 | 7 10 | 4 | 0.6 | 4 | 8 11 | 5 | 0.6 | 4 | 8 7 | 1 | 0.45 | 5 | 9 8 | 2 | 0.6 | 5 | 9 9 | 3 | 0.02 | 5 | 9 Every day new logs are analyzed on different sets of objects and stored in table LOGS. Among other processes, some statistics are computed on the objects contained into these sets and the result are stored in table STATS. These statistic are computed through several logs (identified by the STARTID and ENDID columns). So, what could be the SQL query that would give me the latest computed stats for all the objects with the corresponding log dates. In the given example, the result rows would be: OBJECTID | SETID | FREQUENCY | STARTDATE | ENDDATE ====================================================== 1 | 1 | 0.45 | 2010-02-27 | 2010-03-01 2 | 1 | 0.6 | 2010-02-27 | 2010-03-01 3 | 1 | 0.02 | 2010-02-27 | 2010-03-01 4 | 2 | 0.6 | 2010-02-26 | 2010-02-28 5 | 2 | 0.6 | 2010-02-26 | 2010-02-28 So, the most recent stats for set 1 are computed with logs from feb 27 to march 1 whereas stats for set 2 are computed from feb 26 to feb 28. object 6 is not in the results rows as there is no stat on it within the last period of time. Last thing, I use MySQL. Any Idea ?

    Read the article

  • MySQL move data from one table to another, matching ID's

    - by Reveller
    I have (a.o.) two MySQL tables with (a.o.) the following columns: tweets: ------------------------------------- id text from_user_id from_user ------------------------------------- 1 Cool tweet! 13295354 tradeny 2 Tweeeeeeeet 43232544 bolleke 3 Yet another 13295354 tradeny 4 Something.. 53546443 janusz4 users: ------------------------------------- id from_user num_tweets from_user_id ------------------------------------- 1 tradeny 2235 2 bolleke 432 3 janusz4 5354 I now want to normalize the tweets table, replacing tweets.from_user with an integer that matches users.id. Secondly, I want to fill in the corresponding users.from_user_id, Finally, I want to delete tweets.from_user_id so that the end result would look like: tweets: ------------------------ id text from_user ------------------------ 1 Cool tweet! 1 2 Tweeeeeeeet 2 3 Yet another 1 4 Something.. 3 users: ------------------------------------- id from_user num_tweets from_user_id ------------------------------------- 1 tradeny 2235 13295354 2 bolleke 432 43232544 3 janusz4 5354 53546443 My question is whether one could help me form the proper queries for this. I have only come so far: UPDATE tweets SET from_user = (SELECT id FROM users WHERE from_user = tweets.from_user) WHERE... UPDATE users SET from_user_id = (SELECT from_user_id FROM tweets WHERE from_user = tweets.from_user) WHERE... ALTER TABLE tweets DROP from_user_id Any help would be greatly appreciated :-)

    Read the article

  • cakephp hasMany through and multiselect form

    - by Zoran Kalinic
    I'm using cakephp 2.2.2 and I have a problem with the editing view Models and relationships are: Person hasMany OrganizationPerson Organization hasMany OrganizationPerson OrganizationPerson belongs to Person,Organization A basic hasMany through relationship as found within cake documentation. Tables are: people (id,...) organizations (id,...) organization_people (id, person_id,organization_id,...) In the person add and edit forms there is a select box allowing a user to select multiple organization. The problem I have is, when a user edits an existing person, the associated organizations aren't pre-selected. Here is the code in the PeopleController: $organizations = $this->Person->OrganizationPerson->Organization->find('list'); $this->set(compact('organizations')); Related part of the code in the People/edit code looks like: $this->Form->input('OrganizationPerson.organization_id', array('multiple' => true, 'empty' => false)); This will populate the select field, but it does not pre-select it with the Person's associated organizations. Format and content of the $this-data: Array ( [Person] => Array ( [id] => 1 ... ) [OrganizationPerson] => Array ( [0] => Array ( [id] => 1 [person_id] => 1 [organization_id] => 1 ... ) [1] => Array ( [id] => 2 [person_id] => 1 [organization_id] => 2 ... ) ) ) What I have to add/change in the code to get pre-selected organizations? Thanks in advance!

    Read the article

  • Database contents setting themselves to 0

    - by Luis Armando
    I have a Database that contains 4 tables, however I'm using 1 of them which is separated from the others. In this table I have 4 fields which are varchar and the rest are ints (11 other fields), when the users fill up the DB everything gets saved correctly, however it has happened 3 times so far that the database values for the int's reset to 0 without any apparent reason. At first, I thought, it was because those fields (where the numbers should go) were varchars not ints. However since I changed it, it happened again. I've already double checked my code and I have nothing that even updates or inserts a 0 value. Also I'm using codeigniter and active records which protect against SQL injections AND have XSS filtering enabled, could anyone point out something I might be missing or a reason for this to be happening? Also, I'm pretty sure about the answer of this but, is there ANY way to recover some data?? Other than having to ask everyone to fill in everything again.. =/ ** EDIT ** The Storage Engine is MyISAM and Collation is latin1_swedish_ci, Pack Keys are default, for all intents and purposes it's a normal DB

    Read the article

  • How to fix this simple SQL query?

    - by morpheous
    I have a database with three tables: user_table country_table city_table I want to write ANSI SQL which will allow me to fetch all the user data (i.e. user details including the name of the country of the last school and the name of the city they live in now). The problem I am having is that I have to use a self join, and I am getting slightly confused. The schema is shown below: CREATE TABLE user_table (id int, first_name varchar(16), last_school_country_id int, city_id int); CREATE TABLE country_table (id int, name varchar(32)); CREATE TABLE city_table (id int, country_id int, name varchar(32)); This is the query I have come up with so far, but the results are wrong, and sometimes, the db engine (mySQL), asks me if I want to show all [HUGE NUMBER HERE] results - which makes me suspect that I am unintentionally creating a cartesian product somewhere. Can someone explain what is wrong with this SQL statement, and what I need to do to fix it? SELECT usr.id AS id, usr.first_name, ctry1.name as loc_country_name, ctry2.name as school_country_name, city.name as loc_city_name FROM user_table usr, country_table ctry1, country_table ctry2, city_table city WHERE usr.last_school_country_id=ctry2.id AND usr.city_id=city.id AND city.country_id=ctry1.id AND ctry1.id=ctry2.id;

    Read the article

  • In mysql, is "explain ..." always safe?

    - by tye
    If I allow a group of users to submit "explain $whatever" to mysql (via Perl's DBI using DBD::mysql), is there anything that a user could put into $whatever that would make any database changes, leak non-trivial information, or even cause significant database load? If so, how? I know that via "explain $whatever" one can figure out what tables / columns exist (you have to guess names, though) and roughly how many records are in a table or how many records have a particular value for an indexed field. I don't expect one to be able to get any information about the contents of unindexed fields. DBD::mysql should not allow multiple statements so I don't expect it to be possible to run any query (just explain one query). Even subqueries should not be executed, just explained. But I'm not a mysql expert and there are surely features of mysql that I'm not even aware of. In trying to come up with a query plan, might the optimizer actual execute an expression in order to come up with the value that an indexed field is going to be compared against? explain select * from atable where class = somefunction(...) where atable.class is indexed and not unique and class='unused' would find no records but class='common' would find a million records. Might 'explain' evaluate somefunction(...)? And then could somefunction(...) be written such that it modifies data?

    Read the article

  • .net printing multiple reports in one document (architecture question)

    - by LawsonM
    I understand how to print a single document via the PrintDocument class. However, I want to print multiple reports in one document. Each "report" will consist of charts, tables, etc. I want to have two reports per page. I've studied the few examples I can find on how to combine multiple documents into one; however, they always seem to work by creating a collection of objects (e.g. customer or order) that are then iterated over and drawn in the OnPrintPage method. My problem and hence the "architecture" question is that I don't want to cache the objects required to produce the report since they are very large and memory intensive. I'd simply like the resulting "report". One thought I had was to print the report to a metafile, cache that instead in a "MultiplePrintDocument" class and then position those images appropriately two to a page in the OnPrintPage method. I think this would be a lot more efficient and scalable in my case. But I'm not a professional programmer and can't figure out if I'm barking up the wrong tree here. I think the Graphics.BeginContainer and Graphics.Save methods might be relevant, but can't figure out how to implement or if there is a better way. Any pointers would be greatly appreciated.

    Read the article

  • Linq. Help me tune this!

    - by dtrick
    I have a linq query that is causing some timeout issues. Basically, I have a query that is returning the top 100 results from a table that has approximately 500,000 records. Here is the query: using (var dc = CreateContext()) { var accounts = string.IsNullOrEmpty(searchText) ? dc.Genealogy_Accounts .Where(a => a.Genealogy_AccountClass.Searchable) .OrderByDescending(a => a.ID) .Take(100) : dc.Genealogy_Accounts .Where(a => (a.Code.StartsWith(searchText) || a.Name.StartsWith(searchText)) && a.Genealogy_AccountClass.Searchable) .OrderBy(a => a.Code) .Take(100); return accounts.Select(a => } } Oddly enough it is the first linq query that is causing the timeout. I thought that by doing a 'Take' we wouldn't need to scan all 500k of records. However, that must be what is happening. I'm guessing that the join to find what is 'searchable' is causing the issue. I'm not able to denormalize the tables... so I'm wondering if there is a way to rewrite the linq query to get it to return quicker... or if I should just write this query as a Stored Procedure (and if so, what might it look like). Thanks.

    Read the article

  • Can a Snapshot transaction fail and only partially commit in a TransactionScope?

    - by Travis Brooks
    Greetings I stumbled onto a problem today that seems sort of impossible to me, but its happening...I'm calling some database code in c# that looks something like this: using(var tran = MyDataLayer.Transaction()) { MyDataLayer.ExecSproc(new SprocTheFirst(arg1, arg2)); MyDataLayer.CallSomethingThatEventuallyDoesLinqToSql(arg1, argEtc); tran.Commit(); } I've simplified this a bit for posting, but whats going on is MyDataLayer.Transaction() makes a TransactionScope with the IsolationLevel set to Snapshot and TransactionScopeOption set to Required. This code gets called hundreds of times a day, and almost always works perfectly. However after reviewing some data I discovered there are a handful of records created by "SprocTheFirst" but no corresponding data from "CallSomethingThatEventuallyDoesLinqToSql". The only way that records should exist in the tables I'm looking at is from SprocTheFirst, and its only ever called in this one function, so if its called and succeeded then I would expect CallSomethingThatEventuallyDoesLinqToSql would get called and succeed because its all in the same TransactionScope. Its theoretically possible that some other dev mucked around in the DB, but I don't think they have. We also log all exceptions, and I can find nothing unusual happening around the time that the records from SprocTheFirst were created. So, is it possible that a transaction, or more properly a declarative TransactionScope, with Snapshot isolation level can fail somehow and only partially commit?

    Read the article

< Previous Page | 354 355 356 357 358 359 360 361 362 363 364 365  | Next Page >