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  • How to change Shift + <Keypad Key> behavior ?

    - by LeGEC
    I am used to use the numeric keypad for navigation (e.g. : [KP7] - Start, [KP1] - End, [KP4] - Left, etc... ). I am also used to use it for selection (e.g. : Shift+[KP7] - Select from cursor position to beginning of line, Shift+[KP1] - Select from cursor position to end of line, etc...) With the keyboard configuration installed with Ubuntu, though, Shift+[KP7] prints the character "7", Shift+[KP1] prints "1", etc... How can I change this so that Shift+[KP-key] is not mapped to [key], but to Shift+[KP-key] ?

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  • How to remap CapsLock key to Ctrl in Xubuntu

    - by Evgeny
    I'm trying to remap my CapsLock key to Ctrl key as described here (adding /usr/bin/setxkbmap -option "ctrl:nocaps" command to "Session and Startup"-"Application Autostart"). But this doesn't work in Xubuntu 12.04. When I'm running the same command (/usr/bin/setxkbmap -option "ctrl:nocaps") from terminal everything works as expected. If I change command to: sh -c "/usr/bin/setxkbmap -option \"ctrl:nocaps\"" it again works if I'm running it from terminal, but it doesn't work if I add it to xfce "Session and Startup" configurator. Also when I create a script like this: #!/bin/sh /usr/bin/setxkbmap -option "ctrl:nocaps" and add it to startup via "Session and startup" configurator, it has no effect at all. But if I run this script after login it actually remaps caps key as expected.

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  • Ubuntu 13.10 Security Key

    - by Toby J
    I was attempting to install Ubuntu 13.10 today and it came up with a screen asking for me to setup a security key. In the first place, I'm not sure what a security key is, but It said I would have to enter it everytime I booted Ubuntu so I assume it's the same thing as a logon password in Windows 8. Is there anyway I can bypass this step without setting up a security key or logon password? I hate these things and have always avoided them in Windows. I don't need them as there is never anyone but myself and my wife on our computers. We are retired, no children or nieces, nephews, friends, etc. who ever use our computer and we don't have any security information such as SS #, etc. on it. Also, I quit the installation at this point but I was not seeing any of the screen prompts as listed in the setup instructions on the Ubuntu website. Has the setup for Ubuntu 13.10 changed since these instructions were written? Thanks

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  • Copying an SSH Public Key to a Server

    - by Nathan Arthur
    I'm attempting to setup a git repository on my Dreamhost web server by following the "Setup: For the Impatient" instructions here. I'm having difficulty setting up public key access to the server. After successfully creating my public key, I ran the following command: cat ~/.ssh/[MY KEY].pub | ssh [USER]@[MACHINE] "mkdir ~/.ssh; cat >> ~/.ssh/authorized_keys" ...replacing the appropriate placeholders with the correct values. Everything seemed to go through fine. The server asked for my password, and, as far as I can tell, executed the command. There is indeed a ~/.ssh/authorized_keys file on the server. The problem: When I try to SSH into the server, it still asks for my password. My understanding is that it shouldn't be asking for my password anymore. What am I missing?

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  • Alt/Shift key not released after switching keyboard layout

    - by szx
    Sometimes when I switch layout using either Alt+Shift or Ctrl+Shift the Alt key is not recognized as being released thus if I press e.g. F a File menu opens up. Last time that happend I lost all data I filled into a text form on a webpage because I pressed the Home key while typing and Firefox suddenly went to my home page! Moreoever, it still remains unreleased after hundreds of keypresses like if I'm holding it! Same goes for the Shift key. I would rather file a bug at Launchpad if I could but I have no clue what fucking package name should I type in the ubuntu-bug command! Have anyone else had this issue? Can you suggest a solution or maybe another place to report this bug?

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  • Using MD5 to generate an encryption key from password?

    - by Charles
    I'm writing a simple program for file encryption. Mostly as an academic exercise but possibly for future serious use. All of the heavy lifting is done with third-party libraries, but putting the pieces together in a secure manner is still quite a challenge for the non-cryptographer. Basically, I've got just about everything working the way I think it should. I'm using 128-bit AES for the encryption with a 128-bit key length. I want users to be able to enter in variable-length passwords, so I decided to hash the password with MD5 and then use the hash as the key. I figured this was acceptable--the key is always supposed to be a secret, so there's no reason to worry about collision attacks. Now that I've implemented this, I ran across a couple articles indicating that this is a bad idea. My question is: why? If a good password is chosen, the cipher is supposed to be strong enough on its own to never reveal the key except via an extraordinary (read: currently infeasible) brute-force effort, right? Should I be using something like PBKDF2 to generate the key or is that just overkill for all but the most extreme cryptographic applications?

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  • How to prevent Hibernate from nullifying relationship column during entity removal

    - by Grzegorz
    I have two entities, A and B. I need to easily retrieve entities A, joined with entities B on the condition of equal values of some column (some column from A equal to some column in B). Those columns are not primary or foreign keys, they contain same business data. I just need to have access from each instance of A to the collection of B's with the same value of this column. So I model it like this: class A { @OneToMany @JoinColumn(name="column_in_B", referencedColumnName="column_in_A") Collection<B> bs; This way, I can run queries like "select A join fetch a.bs b where b...." (Actually, the real relationship here is many-to-many. But when I use @ManyToMany, Hibernate forces me to use join table, which doesnt exist here. So I have to use @OneToMany as workaround). So far so good. The main problem is: whenever I delete an instance of A, hibernate calls "Update B set column_in_B = null", becuase it thinks the column_in_B is foreign key pointing at primary key in A (and because row in A is deleted, it tries to clean the foreign key in B). BUT the column_in_B IS NOT a foreign key, and can't be modified, because it causes data lost (and this column is NOT NULL anyway in my case, causing data integerity exception to be thrown). Plese help me with this. How to model such relationships with Hibernate? (I would call it "virtual relationships", or "secondary relationships" or so: as they are not based on foreign keys, they are just some shortcuts which allows for retrieving related objects and quering for them with HQL)

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  • Relationship Modelling in Core Data

    - by Stevie
    Hi there, I'm fairly new to Objective C and Core Data and have a problem designing a case where players team up one-on-one and have multiple matches that end up with a specific result. With MySQL, I would have a Player table (player primary key, name) and a match table (player A foreign key, player B foreign key, result). Now how do I do this with Core Data? I can easily tie a player entity to a match entity using a relationship. But how do I model the inverse direction for the second player ref. in the match entity? Player Name: Attribute Match: Relationship Match Match Result: Attribute PlayerA: Relationship to Player (<- Inverse to Player.Match) PlayerB: Relationship to Player (<- Inverse to ????) Would be great if someone could give me an idea on this! Thanks, Stevie.

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  • Model relationship types in cakePhP

    - by kwokwai
    I have checked out the cookbook web site of cakephp that there are four types Model relationship: http://book.cakephp.org/view/79/Relationship-Types Since the one I am more familiar with is belongsTo, I am not sure when I need to use hasManay and HABTM. What will be the result to my web site if I used a wrong Model relationship type? Please advise.

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  • Entity Framework use of indexes and foreign keys

    - by David
    I want to be able to search a table quite quickly using the Entity Framework, say if I have a Contacts table, a JobsToDo table and a matrix table linking the two tables e.g Contacts_JobsToDo_Mtx and I specify two foreign keys in the Contacts_JobsToDo_Mtx table, if I wanted to search this Mtx table, do I need to specify an index on the two foreign keys? Or by the fact that they are two foreign keys are they considered indexed on them anyway? Will the Entity Framework be able to search through the Mtx table quickly without having to specfiy an index on both keys? Thanks!

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  • GetOleDbSchemaTable Foreign Keys on Sql Server 2005

    - by haxelit
    I'm trying to get the Foreign Keys for a table in my SQL Server 2005 database. I'm using the GetOleDbSchemaTable function right now: DataTable schemaTable = connection.GetOleDbSchemaTable( OleDbSchemaGuid.Foreign_Keys, new object[] { null, null, null, "TABLE" }); This pulls back the right foreign keys, the only problem is that the UpdateRule and DeleteRule are set to "No Action". If I browse to the same table in SSMS I can see that my DeleteRule is "Set NULL". Does the GetOleDbSchemaTable function not return the proper foreign key rules ? Has any one else ran into this problem ?

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  • belongs_to with a custom class_name not producing proper foreign key in Rails 3

    - by Tony
    I am updating an application to Rails 3 and I am having trouble creating a custom foreign key. I have something like this: class Product < ActiveRecord::Base belongs_to :owner, :class_name => 'User' ... end class User < ActiveRecord::Base has_many :products ... end class ProductsController < ApplicationController before_filter :authenticate_user! def index @products = current_user.products end end The view: <%- @products.each do |p| -%> <%= p.created_at %><br /> <%- end -%> I get this error in my Rails log: Mysql::Error: Unknown column 'products.user_id' in 'where clause': SELECT `products`.* FROM `products` WHERE (`products`.user_id = 1) It should see the belongs_to :owner and look for a foreign key called owner_id. I even tried explicitly setting the foreign key and that does not work. I also checked lighthouse for a possible Rails 3 bug but no luck.

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  • Modelling a manyToMany relationship with attributes

    - by Javi
    Hello, I have a ManyToMany relationship between two classes, for instance class Customer and class Item. A customer can buy several items and an item can be bought by different customers. I need to store extra information in this relationship, for example the day when the item was bought. I wonder how is this usually modelled in JPA, cause I'm not sure how to express this in code. Do I have to create a new class to model all the attributes of the relationship and make a manyToMany relationship between the other classes or is a better way to do this? Thanks

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  • Entity Relationship Multiple 1:1's

    - by Evan
    I have an application where I have a generic object (table) called Hull. Each hull in the table is unique. I have another object that has three hulls, but they are specifically the Port_Hull, Center_Hull and Starboard_Hull. Rather than create a One to Many relationship, I was trying to create a one to one relationship for each one, but this results in numerous errors unless I make the relationship from Hull to Vessel one to many (which it is not). Any idea how I go about this, or should I abandon the concept and make the vessel to hull relationship one to many and deal with lists that always have three entries? p.s. Using uniqueidentifiers as many users can be adding records while disconnected. Hull Table HullID uniqueidentifier (primary key) plus bunch of hull data fields Vessel Table VesselID uniqueidentifier (primary key) MainHullID uniqueidentifier (tried as key and non-key) PortHullID uniqueidentifier StarboardHullID uniqueidentifier plus bunch of Vessel data fields

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  • Identifying which value of a multi-row inserts fails foreign key constraint

    - by Jonathan
    I have a multi-row insert that looks something like: insert into table VALUES (1, 2, 3), (4, 5, 6), (7, 8, 9); Assume the first attribute (1, 4, 7) is a foreign key to another table and assume that this referenced table does not have the value '4'. A MySQLExeption is thrown with error code 1452. EXCEPTION: Cannot add or update a child row: a foreign key constraint fails (dbName/tableName, CONSTRAINT id FOREIGN KEY (customer_id) REFERENCES referencedTable (customer_id)) Is there a way to identify which value caused the error? I would love to give my user an error message that said something like: Error: '4' does not exist in the referenced table. I am using the .NET mysql connector to execute the insert. Thanks- Jonathan

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  • In this example, would Customer or AccountInfo properly be the entity group parent?

    - by Badhu Seral
    In this example, the Google App Engine documentation makes the Customer the entity group parent of the AccountInfo entity. Wouldn't AccountInfo encapsulate Customer rather than the other way around? Normally I would think of an AccountInfo class as including all of the information about the Customer. import javax.jdo.annotations.IdGeneratorStrategy; import javax.jdo.annotations.PersistenceCapable; import javax.jdo.annotations.Persistent; import javax.jdo.annotations.PrimaryKey; import com.google.appengine.api.datastore.Key; import com.google.appengine.api.datastore.KeyFactory; @PersistenceCapable public class AccountInfo { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Key key; public void setKey(Key key) { this.key = key; } } // ... KeyFactory.Builder keyBuilder = new KeyFactory.Builder(Customer.class.getSimpleName(), "custid985135"); keyBuilder.addChild(AccountInfo.class.getSimpleName(), "acctidX142516"); Key key = keyBuilder.getKey(); AccountInfo acct = new AccountInfo(); acct.setKey(key); pm.makePersistent(acct);

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  • How can I Query only __key__ on a Google Appengine PolyModel child?

    - by Gabriel
    So the situation is: I want to optimize my code some for doing counting of records. So I have a parent Model class Base, a PolyModel class Entry, and a child class of Entry Article: How would I query Article.key so I can reduce the query load but only get the Article count. My first thought was to use: q = db.GqlQuery("SELECT __key__ from Article where base = :1", i_base) but it turns out GqlQuery doesn't like that because articles are actually stored in a table called Entry. Would it be possible to Query the class attribute? something like: q = db.GqlQuery("select __key__ from Entry where base = :1 and :2 in class", i_base, 'Article') neither of which work. Turns out the answer is even easier. But I am going to finish this question because I looked everywhere for this. q = db.GqlQuery("select __key__ from Entry where base = :1 and class = :2", i_base, 'Article')

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  • Is it a good idea to use a computed column as part of a primary key ?

    - by Brann
    I've got a table defined as : OrderID bigint NOT NULL, IDA varchar(50) NULL, IDB bigint NULL, [ ... 50 other non relevant columns ...] The natural primary key for this table would be (OrderID,IDA,IDB), but this it not possible because IDA and IDB can be null (they can both be null, but they are never both defined at the same time). Right now I've got a unique constraint on those 3 columns. Now, the thing is I need a primary key to enable transactional replication, and I'm faced with two choices : Create an identity column and use it as a primary key Create a non-null computed column C containing either IDA or IDB or '' if both columns were null, and use (OrderID,C) as my primary key. The second alternative seams cleaner as my PK would be meaningful, and is feasible (see msdn link), but since I've never seen this done anywhere, I was wondering if they were some cons to this approach.

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  • Setting 0/1-to-1 relationship in SQLAlchemy?

    - by Timmy
    is there a proper way of setting up a 0/1-to-1 relationship? i want to be able to check if the related item exists without creating it: if item.relationship is None: item.relationship = item2() but it creates the insert statements on the if statement

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  • How to change a primary key in SQL to auto_increment?

    - by Jian Lin
    I have a table in MySQL that has a primary key: mysql> desc gifts; +---------------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +---------------+-------------+------+-----+---------+-------+ | giftID | int(11) | NO | PRI | NULL | | | name | varchar(80) | YES | | NULL | | | filename | varchar(80) | YES | | NULL | | | effectiveTime | datetime | YES | | NULL | | +---------------+-------------+------+-----+---------+-------+ but I wanted to make it auto_increment. The following statement failed. How can it be modified so that it can work? thanks mysql> alter table gifts modify giftID int primary key auto_increment; ERROR 1068 (42000): Multiple primary key defined

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  • Does introducing foreign keys to MySQL reduce performance

    - by Tam
    I'm building Ruby on Rails 2.3.5 app. By default, Ruby on Rails doesn't provide foreign key contraints so I have to do it manually. I was wondering if introducing foreign keys reduces query performance on the database side enough to make it not worth doing. Performance in this case is my first priority as I can check for data consistency with code. What is your recommendation in general? do you recommend using foreign keys? and how do you suggest I should measure this?

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  • Need to get to the foreign keys of an entity marked as "Deleted" for auditing

    - by Abhijeet Patel
    I'm using v1 of EF(.NET 3.5 SP1). I'm subscribing to the SavingChanges event of the ObjectContext wherein I audit deletes for a particular entity type. I need to get to the foreign keys of the entity being deleted i.e EntityKeys of the related entities (RelatedEnds) but the EntityKeys of the related entities are nulls. Is there any way to get to the foreign keys of an entity which has been marked for deletion? Does EF null out the EntityKeys of all RelatedEnds for an entity which has been marked for deletion? If so, is there a way I can get hold of the foreign keys?

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