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  • Is scala's cake pattern possible with parametrized components?

    - by Nicolas
    Parametrized components work well with the cake pattern as long as you are only interested in a unique component for each typed component's, example: trait AComponent[T] { val a:A[T] class A[T](implicit mf:Manifest[T]) { println(mf) } } class App extends AComponent[Int] { val a = new A[Int]() } new App Now my application requires me to inject an A[Int] and an A[String], obviously scala's type system doesn't allow me to extends AComponent twice. What is the common practice in this situation ?

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  • Why One-to-one relationship dosen't work?

    - by eugenn
    I'm trying to create a very simple relationship between two objects. Can anybody explain me why I can't find the Company object via findBy method? class Company { String name String desc City city static constraints = { city(unique: true) } } class City { String name static constraints = { } } class BootStrap { def init = { servletContext -> new City(name: 'Tokyo').save() new City(name: 'New York').save() new Company(name: 'company', city: City.findByName('New York')).save() def c = Company.findByName('company') // Why c=null????! } def destroy = { } }

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  • Assigning IDs to instances of a class (Pythonic)

    - by mellort
    I want to have each instance of some class have a unique integer identifier based on the order that I create them, starting with (say) 0. In Java, I could do this with a static class variable. I know I can emulate the same sort of behavior with Python, but what would be the most 'Pythonic' way to do this? Thanks

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  • Updating value in Linq to SQL IEnumerable

    - by Learner
    Using Linq to SQL: if(!parentlist.childlist.Contains(row1)) parentlist.childlist.Add(row1); else How do I update the required childlist row with row1? Each row of the child list has a unique id. parentlist implements IEnumerable and childlist is IList.

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  • MySQL not using index on DATE when used with '<' or '>' operators?

    - by Haroldo
    I'm using explain to test these queries. The col type is DATE this uses index: explain SELECT events.* FROM events WHERE events.date = '2010-06-11' this doesnt explain SELECT events.* FROM events WHERE events.date >= '2010-06-11' index as follows (phpmyadmin) Action Keyname Type Unique Packed Field Cardinality Collation Null Comment Edit Drop PRIMARY BTREE Yes No event_id 18 A Edit Drop date BTREE No No date 0 A i notice cardinality is 0, though there are some rows with the same date..

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  • Can two threads of the same process produce the same GUID?

    - by mark
    Dear ladies and sirs. If two threads in a process generate a new GUID concurrently using .NET API (Guid.NewGuid()) is it possible that the two GUIDs will be identical? Thanks. UPDATE I want to get practical. I know that it is widely assumed that GUIDs are unique for all practical purposes. I am wondering if I can treat GUIDS produced by the different threads of the same process in the same manner.

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  • Is possible to generate constant value during compilation?

    - by AOI Karasu
    I would like my classes to be identified each type by an unique hash code. But I don't want these hashed to be generated every time a method, eg. int GetHashCode(), is invoked during runtime. I'd like to use already generated constants and I was hoping there is a way to make the compiler do some come computing and set these constants. Can it be done using templates? Could you give me some example, if it is possible.

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  • C#:checking existing record in database Mysql

    - by Meko
    HI.I searched this question inform and I found solution to change column property Unique Index.Now If I try to insert same record cmd.ExecuteNonQuery() gives error that record exist ,but how can use this exception to give user a message that record exist and must enter new one ? I am trying to make some thing like if(cmd.ExecuteNonQuery() !=true ) { MessageBox.Show("User Exists"); } But I dont know what returns cmd.ExecuteNonQuery() ? Or I must get records using reader in table and compare them with text in Textfiel?

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  • Why this query is so slow?

    - by Silver Light
    This query appears in mysql slow query log: it takes 11 seconds. INSERT INTO record_visits ( record_id, visit_day ) VALUES ( '567', NOW() ); The table has 501043 records and it's structure looks like this: CREATE TABLE IF NOT EXISTS `record_visits` ( `id` int(11) NOT NULL AUTO_INCREMENT, `record_id` int(11) DEFAULT NULL, `visit_day` date DEFAULT NULL, `visit_cnt` bigint(20) DEFAULT '1', PRIMARY KEY (`id`), UNIQUE KEY `record_id_visit_day` (`record_id`,`visit_day`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 ; What could be wrong? Why this INSERT takes so long?

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  • How should a Gnome applet store its configuration data?

    - by George Edison
    I have a Gnome applet written in Python. In order to save configuration data/settings, it creates a file ~/.appname. However, this prevents multiple instances of the applet from being added to the panel because each cannot have its own settings. How can I store the settings in a way that allows each instance to have its own unique settings? Update: I specifically want to know how to store settings per instance.

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  • django multi-language (i18n) and seo

    - by fumer
    hi, I am developing a multi-language site in django. In order to improve SEO, i will give every language version a unique URL like below, english: www.foo.com/en/index.html french: www.foo.com/fr/index.html chinese: www.foo.com/zh/index.html However, Django looks for a "django_language" key in user's session or cookie to determine language in default, so,Despite which language user chose, URL is always the same. for instance: http://www.foo.com/index.html how to resolve this problem ? thank you!

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  • (database design):Which tables should be created for all kindes files (images, attached email files,

    - by meyosef
    Hi, I new in database design: I have question with my own few solution,what do you thinks?: Which tables should be created for all kinds files (images, attached email files,text files for store email body, etc..) that stored in my online store? *option 1:use seperate table for files types * files{ id files_types_id FK file_path file_extension } files_types{ id type_name (unique) } *option 2: use bool field for each file type * files{ id file_path file_extension is_image_main is_image_icon is_image_logo is_pdf_file is_text_file } **option 3: use 1 enum field 'file_type' for each file type ** files{ id file_path file_extension file_type (image_main,image_icon,image_logo,image_main,pdf,text) **enum** } Thanks you, Yosef

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  • Does array contain a specific value

    - by padatronic
    Hi chaps, I have an array of nsdictionaries and one key is ID (which is unique) I simply want to see if the the array of dictionaries contains a specific ID. Really simple but its friday and after statiny up watching the election i think my brain is melting. Any help would be great. Thanks

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  • Merging list problem

    - by Martin Malmstrøm
    Sorry about the bad heading, but the question was not easy to compress into one sentence... I have two lists of contigs (list1 and list2). They contain mostly unique contigs, but with some overlap. I want to compare list1 and list2 and then create a list3 that contains all contigs in list1 minus those also present in list2. Is this possible with a simple cat/paste/grep/sort/uniq kind of batch command? Thanks!

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  • jpa-Google app engine

    - by megala
    I had created entity in google app engie datastore using JPA.I set the id as follows @Id @GeneratedValue(strategy=GenerationType.SEQUENCE) private Long s; After i deployed my applicaiton it give identity (i.e) unique value.but igive 1001,1002,1003 ....as id.But i wnat 1,2,3,4,5 like that.how to achive this? Thanks in advance

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  • How to have multiple parts of a website in one page

    - by stas
    I want to make a website that will have multiple pages, but because of a unique navigation bar, I cannot simply link to a new file for each page. What is the best way to accomplish this. Some possibilities that I can think of are having all of them on one page, but using css and javascript to move the other pages offscreen, or using iframes and loading them with javascript. Could someone please direct me to some examples or tutorials?

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  • sqlite, UPDATE OR REPLACE

    - by acidzombie24
    I do something like UPDATE OR REPLACE someTable SET a=1, b=2 WHERE c=3 I expect if it doesnt exist it will be inserted into the DBs. But nothing happens and i get no errors. How can i insert data, replace it if it already exist and use a where for the condition (instead of replacing BC of a unique ID)

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  • Adding a clustered index to a SQL table: what dangers exist for a live production system?

    - by MoSlo
    Right, keep in mind i need to describe this by abstracting all possible confidential info: I've been put in charge of a 10-year old transactional system of which the majority business logic is implemented at database level (triggers, stored procedures etc). Win2000 server, MSSQL 2000 Enterprise. No immediate plans for replacing/updating the system are being considered :( The core process is a program that executes transactions - specifically, it executes a stored procedure with various parameters, lets call it sp_ProcessTrans. The program executes the stored procedure at asynchronous intervals. By itself, things work fine. But there are 30 instances of this program on remotely located workstations, all of them asynchronously executing sp_ProcessTrans and then retrieving data from the SQL server (execution is pretty regular - ranging 0 to 60 times a minute, depending on what items the program instance is responsible for) . Performance of the system has dropped considerably with 10 yrs of data growth: the reason is the deadlocks and specifically deadlock wait times. The deadlock is on the Employee table. I have discovered: In sp_ProcessTrans' execution, it selects from an Employee table 7 times (dont ask) The select is done on a field that is NOT the primary key No index exists on this field. Thus a table scan is performed. 7 times. per transaction So the reason for deadlocks is clear. I created a non-unique ordered clustered index on the field (field looks good, almost unique, NUM(7), very rarely changes). Immediate improvement in the test environment. The problem is that i cannot simulate the deadlocks in a test environment (I'd need 30 workstations; i'd need to simulate 'realistic' activity on those stations, so visualization is out). I need to know if i must schedule downtime. Creating an index shouldn't be a risky operation for MSSQL, but is there any danger (data corruption in transactions/select statements/extra wait time etc) to create this field index on the production database while the transactions are still taking place? (although i can select a time when transactions are fairly quiet through the 30 stations) Are there any hidden dangers i'm not seeing (not looking forward to needing to restore the DB if something goes wrong, restoring would take a lot of time with 10yrs of data).

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  • Can an html element have multiple ids?

    - by webmat
    I understand that an id must be unique within an HTML/XHTML page. My question is, for a given element, can I assign multiple ids to it? <div id="nested_element_123 task_123"></div> I realize I have an easy solution with simply using a class. I'm just curious about using ids in this manner.

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  • SQL subquery question

    - by seo20
    I have the following SQL SELECT Seq.UserSessionSequenceID, Usr.SessionGuid, Usr.UserSessionID, Usr.SiteID, Seq.Timestamp, Seq.UrlTitle, Seq.Url FROM tblUserSession Usr INNER JOIN tblUserSessionSequence Seq ON Usr.UserSessionID = Seq.UserSessionID WHERE (Usr.Timestamp > DATEADD(mi, -45, GETDATE())) AND (Usr.SiteID = 15) ORDER BY Usr.Timestamp DESC Pretty simple stuff. There are by nature multiple UserSessionIDs rows in tblUserSessionSequence. I ONLY want to return the latest (top 1) row with unique UserSessionID. How do I do that?

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