Search Results

Search found 6628 results on 266 pages for 'foreign keys'.

Page 6/266 | < Previous Page | 2 3 4 5 6 7 8 9 10 11 12 13  | Next Page >

• How do I delete a foreign key in SQLAlchemy?

  - by Travis

  I'm using SQLAlchemy Migrate to keep track of database changes and I'm running into an issue with removing a foreign key. I have two tables, t_new is a new table, and t_exists is an existing table. I need to add t_new, then add a foreign key to t_exists. Then I need to be able to reverse the operation (which is where I'm having trouble). t_new = sa.Table("new", meta.metadata, sa.Column("new_id", sa.types.Integer, primary_key=True) ) t_exists = sa.Table("exists", meta.metadata, sa.Column("exists_id", sa.types.Integer, primary_key=True), sa.Column( "new_id", sa.types.Integer, sa.ForeignKey("new.new_id", onupdate="CASCADE", ondelete="CASCADE"), nullable=False ) ) This works fine: t_new.create() t_exists.c.new_id.create() But this does not: t_exists.c.new_id.drop() t_new.drop() Trying to drop the foreign key column gives an error: 1025, "Error on rename of '.\my_db_name\#sql-1b0_2e6' to '.\my_db_name\exists' (errno: 150)" If I do this with raw SQL, i can remove the foreign key manually then remove the column, but I haven't been able to figure out how to remove the foreign key with SQLAlchemy? How can I remove the foreign key, and then the column?

  Read the article

• Why don't my Fn keys work for brightness or media after upgrading?

  - by Adina G

  I recently upgraded from 11.04 to 11.10. After the upgrade, I can no longer adjust the screen brightness or the volume using keyboard (before the upgrade, using Fn+F4, Fn+F11, etc. worked). Using Fn+F2 to disable wireless still works, so I guess the Fn key itself is being recognised. I tried to follow the instructions here, but I don't have a file in /etc/X11 called xorg.conf. I also tried following this workaround, but it had no noticeable effect. I've also tried going to Settings ? Keyboard ? Shortcuts and reassigning the brightness and volume controls, both to the default keys and to new combinations. These changes don't have an effect even after rebooting. Googling has found bug reports where pressing the media keys brings up a "no entry sign" rather than changing the volume. When I press the keys there's no response at all. I've also seen various people say a workaround is to have totem running in the background; this doesn't work for me either. Finally, I tried installing keytouch; I was able to install keytouch-editor but got the message "Unable to locate package keytouch". Any more ideas? I'd be very grateful if anyone could help me (even by pointing to a thread I've missed)!

  Read the article

• Which Table Should be Master and Child in Database Design

  - by Jason

  I am quickly learning the ins and outs of database design (something that, as of a week ago, was new to me), but I am running across some questions that don't seem immediately obvious, so I was hoping to get some clarification. The question I have right is about foreign keys. As part of my design, I have a Company table. Originally, I had included address information directly within the table, but, as I was hoping to achieve 3NF, I broke out the address information into its own table, Address. In order to maintain data integrity, I created a row in Company called "addressId" as an INT and the Address table has a corresponding addressId as its primary key. What I'm a little bit confused about (or what I want to make sure I'm doing correctly) is determining which table should be the master (referenced) table and which should be the child (referencing) table. When I originally set this up, I made the Address table the master and the Company the child. However, I now believe this is wrong due to the fact that there should be only one address per Company and, if a Company row is deleted, I would want the corresponding Address to be removed as well (CASCADE deletion). I may be approaching this completely wrong, so I would appreciate any good rules of thumb on how to best think about the relationship between tables when using foreign keys. Thanks!

  Read the article

• Keys used the least in vim.

  - by SpawnST

  Can some one offer me a list of keys probably not be used in most situations?Then I can do some mapping with them.Thanks.

  Read the article

• How should I define a composite foreign key for domain constraints in the presence of surrogate keys

  - by Samuel Danielson

  I am writing a new app with Rails so I have an id column on every table. What is the best practice for enforcing domain constraints using foreign keys? I'll outline my thoughts and frustration. Here's what I would imagine as "The Rails Way". It's what I started with. Companies: id: integer, serial company_code: char, unique, not null Invoices: id: integer, serial company_id: integer, not null Products: id: integer, serial sku: char, unique, not null company_id: integer, not null LineItems: id: integer, serial invoice_id: integer, not null, references Invoices (id) product_id: integer, not null, references Products (id) The problem with this is that a product from one company might appear on an invoice for a different company. I added a (company_id: integer, not null) to LineItems, sort of like I'd do if only using natural keys and serials, then added a composite foreign key. LineItems (product_id, company_id) references Products (id, company_id) LineItems (invoice_id, company_id) references Invoices (id, company_id) This properly constrains LineItems to a single company but it seems over-engineered and wrong. company_id in LineItems is extraneous because the surrogate foreign keys are already unique in the foreign table. Postgres requires that I add a unique index for the referenced attributes so I am creating a unique index on (id, company_id) in Products and Invoices, even though id is simply unique. The following table with natural keys and a serial invoice number would not have these issues. LineItems: company_code: char, not null sku: char, not null invoice_id: integer, not null I can ignore the surrogate keys in the LineItems table but this also seems wrong. Why make the database join on char when it has an integer already there to use? Also, doing it exactly like the above would require me to add company_code, a natural foreign key, to Products and Invoices. The compromise... LineItems: company_id: integer, not null sku: integer, not null invoice_id: integer, not null does not require natural foreign keys in other tables but it is still joining on char when there is a integer available. Is there a clean way to enforce domain constraints with foreign keys like God intended, but in the presence of surrogates, without turning the schema and indexes into a complicated mess?

  Read the article

• Does Rails need database-level constraints?

  - by shrimpy

  I have the same problem as in the following post. So I am wondering, why doesn't Rails support generating foreign keys by default? Isn't it necessary? Or are we supposed to do it manually?

  Read the article

• Limit foreign key choices in select in an inline form in admin

  - by mightyhal

  Edited :-) Hopefully a bit clearer now. The logic is of the model is: A Building has many Rooms A Room may be inside another Room (a closet, for instance--ForeignKey on 'self') A Room can only in inside of another Room in the same building (this is the tricky part) Here's the code I have: #spaces/models.py from django.db import models class Building(models.Model): name=models.CharField(max_length=32) def __unicode__(self): return self.name class Room(models.Model): number=models.CharField(max_length=8) building=models.ForeignKey(Building) inside_room=models.ForeignKey('self',blank=True,null=True) def __unicode__(self): return self.number and: #spaces/admin.py from ex.spaces.models import Building, Room from django.contrib import admin class RoomAdmin(admin.ModelAdmin): pass class RoomInline(admin.TabularInline): model = Room extra = 2 class BuildingAdmin(admin.ModelAdmin): inlines=[RoomInline] admin.site.register(Building, BuildingAdmin) admin.site.register(Room) The inline will display only rooms in the current building (which is what I want). The problem, though, is that for the inside_room drop down, it displays all of the rooms in the Rooms table (including those in other buildings). In the inline of rooms, I need to limit the inside_room choices to only rooms which are in the current building being displayed by the main form. I can't figure out a way to do it with either a limit_choices_to in the model, nor can I figure out how exactly to override the admin's inline formset properly (I feel like I should be somehow create a custom inline form, pass the building_id of the main form to the custom inline, then limit the queryset for the field's choices based on that--but I just can't wrap my head around how to do it). Maybe this is too complex for the admin site, but it seems like something that would be generally useful... Thanks again for your help!

  Read the article

• Language of variable names? (native foreign language speakers)

  - by Jj

  We are a spanish speaking development team, we code in django and we all are pretty fluent in english, as all documentation, sample code, APIs, etc come in english. On our last project we chose to name all the variables, class names, modules, files and such in english, even though the whole application was in spanish, we kept a strings file where all our spanish was stored. We did this because it seemed more natural to read the whole code in one language, since keywords, constructs and dependencies have names in english. On new projects we are starting, we are having second thoughts about other teams mantaining our code or just having 3rd parties having to deal with templates or context in spanish. Do you know of any best practice on this matter?

  Read the article

• EF4 CTP5 - Map foreign key without object references?

  - by anon

  I feel like this should have a simple answer, but I can't find it. I have 2 POCOs: public class Category { public int Id { get; set; } public string Name { get; set; } } public class Product { public int Id { get; set; } public int CategoryId { get; set; } } Notice that there are no object references on either POCO. With Code-First, how do I make EF4 CTP5 define a relationship between the two database tables? (I know this is an unusual scenario, but I am exploring what's possible and what's not with Code-First)

  Read the article

• MySql not storing foreign characters correctly

  - by acidzombie24

  On SQLITE this way fine. I switch to mysql and instead of ??? i get ???. The column is TEXT or sometimes VARCHAR(255) (i believe its VARCHAR(255) in this case). How do i have mysql save the characters properly?

  Read the article

• Creating Two Cascading Foreign Keys Against Same Target Table/Col

  - by alram

  I have the following tables: user (userid int [pk], name varchar(50)) action (actionid int [pk], description nvarchar(50)) being referenced by another table that captures the relationship: <user1> <action>'s <user2>. I did this with the following table: userAction (userActionId int [pk], actionid int [fk: action.actionid], **userId1 int [fk ref's user.userid; on del/update cascade], userId2 int [fk ref's user.userid; on del/update cascade]**). However, when I try to save the userAction table i get an error because I have two cascading fk's against user.userid. Is there any way to remedy this or must I use a trigger?

  Read the article

• Multiple Foriegn Keys from One Table linking to single Primary Key in second Table

  - by croker10

  Hi all, I have a database with three tables, a household table, an adults table and a users table. The Household table contains two foreign keys, iAdult1ID and iAdult2ID. The Users table has a iUserID primary key and the Adult table has a corresponding iUserID foreign key. One of the columns in the Users table is strUsername, an e-mail address. I am trying to write a query that will allow me to search for an e-mail address for either adult that has a relation to the household. So I have two questions, assuming that all the values are not null, how can I do this? And two, in reality, iAdult2ID can be null, is it still possible to write a query to do this? Thanks for your help. Let me know if you need any more information.

  Read the article

• New MySQL Cluster 7.3 Previews: Foreign Keys, NoSQL Node.js API and Auto-Tuned Clusters

  - by Mat Keep

  At this weeks MySQL Connect conference, Oracle previewed an exciting new wave of developments for MySQL Cluster, further extending its simplicity and flexibility by expanding the range of use-cases, adding new NoSQL options, and automating configuration. What’s new: Development Release 1: MySQL Cluster 7.3 with Foreign Keys Early Access “Labs” Preview: MySQL Cluster NoSQL API for Node.js Early Access “Labs” Preview: MySQL Cluster GUI-Based Auto-Installer In this blog, I'll introduce you to the features being previewed. Review the blogs listed below for more detail on each of the specific features discussed. Save the date!: A live webinar is scheduled for Thursday 25th October at 0900 Pacific Time / 1600UTC where we will discuss each of these enhancements in more detail. Registration will be open soon and published to the MySQL webinars page MySQL Cluster 7.3: Development Release 1 The first MySQL Cluster 7.3 Development Milestone Release (DMR) previews Foreign Keys, bringing powerful new functionality to MySQL Cluster while eliminating development complexity. Foreign Key support has been one of the most requested enhancements to MySQL Cluster – enabling users to simplify their data models and application logic – while extending the range of use-cases for both custom projects requiring referential integrity and packaged applications, such as eCommerce, CRM, CMS, etc. Implementation The Foreign Key functionality is implemented directly within the MySQL Cluster data nodes, allowing any client API accessing the cluster to benefit from them – whether they are SQL or one of the NoSQL interfaces (Memcached, C++, Java, JPA, HTTP/REST or the new Node.js API - discussed later.) The core referential actions defined in the SQL:2003 standard are implemented: CASCADE RESTRICT NO ACTION SET NULL In addition, the MySQL Cluster implementation supports the online adding and dropping of Foreign Keys, ensuring the Cluster continues to serve both read and write requests during the operation.  This represents a further enhancement to MySQL Cluster's support for on0line schema changes, ie adding and dropping indexes, adding columns, etc.  Read this blog for a demonstration of using Foreign Keys with MySQL Cluster.  Getting Started with MySQL Cluster 7.3 DMR1: Users can download either the source or binary and evaluate the MySQL Cluster 7.3 DMR with Foreign Keys now! (Select the Development Release tab). MySQL Cluster NoSQL API for Node.js Node.js is hot! In a little over 3 years, it has become one of the most popular environments for developing next generation web, cloud, mobile and social applications. Bringing JavaScript from the browser to the server, the design goal of Node.js is to build new real-time applications supporting millions of client connections, serviced by a single CPU core. Making it simple to further extend the flexibility and power of Node.js to the database layer, we are previewing the Node.js Javascript API for MySQL Cluster as an Early Access release, available for download now from http://labs.mysql.com/. Select the following build: MySQL-Cluster-NoSQL-Connector-for-Node-js Alternatively, you can clone the project at the MySQL GitHub page.  Implemented as a module for the V8 engine, the new API provides Node.js with a native, asynchronous JavaScript interface that can be used to both query and receive results sets directly from MySQL Cluster, without transformations to SQL. Figure 1: MySQL Cluster NoSQL API for Node.js enables end-to-end JavaScript development Rather than just presenting a simple interface to the database, the Node.js module integrates the MySQL Cluster native API library directly within the web application itself, enabling developers to seamlessly couple their high performance, distributed applications with a high performance, distributed, persistence layer delivering 99.999% availability. The new Node.js API joins a rich array of NoSQL interfaces available for MySQL Cluster. Whichever API is chosen for an application, SQL and NoSQL can be used concurrently across the same data set, providing the ultimate in developer flexibility.  Get started with MySQL Cluster NoSQL API for Node.js tutorial MySQL Cluster GUI-Based Auto-Installer Compatible with both MySQL Cluster 7.2 and 7.3, the Auto-Installer makes it simple for DevOps teams to quickly configure and provision highly optimized MySQL Cluster deployments – whether on-premise or in the cloud. Implemented with a standard HTML GUI and Python-based web server back-end, the Auto-Installer intelligently configures MySQL Cluster based on application requirements and auto-discovered hardware resources Figure 2: Automated Tuning and Configuration of MySQL Cluster Developed by the same engineering team responsible for the MySQL Cluster database, the installer provides standardized configurations that make it simple, quick and easy to build stable and high performance clustered environments. The auto-installer is previewed as an Early Access release, available for download now from http://labs.mysql.com/, by selecting the MySQL-Cluster-Auto-Installer build. You can read more about getting started with the MySQL Cluster auto-installer here. Watch the YouTube video for a demonstration of using the MySQL Cluster auto-installer Getting Started with MySQL Cluster If you are new to MySQL Cluster, the Getting Started guide will walk you through installing an evaluation cluster on a singe host (these guides reflect MySQL Cluster 7.2, but apply equally well to 7.3 and the Early Access previews). Or use the new MySQL Cluster Auto-Installer! Download the Guide to Scaling Web Databases with MySQL Cluster (to learn more about its architecture, design and ideal use-cases). Post any questions to the MySQL Cluster forum where our Engineering team and the MySQL Cluster community will attempt to assist you. Post any bugs you find to the MySQL bug tracking system (select MySQL Cluster from the Category drop-down menu) And if you have any feedback, please post them to the Comments section here or in the blogs referenced in this article. Summary MySQL Cluster 7.2 is the GA, production-ready release of MySQL Cluster. The first Development Release of MySQL Cluster 7.3 and the Early Access previews give you the opportunity to preview and evaluate future developments in the MySQL Cluster database, and we are very excited to be able to share that with you. Let us know how you get along with MySQL Cluster 7.3, and other features that you want to see in future releases, by using the comments of this blog.

  Read the article

• Is it reasonable to have multiple SSH keys?

  - by Leonid Shevtsov

  So far I've created a separate SSH key for each server I need to login to (for each purpose, to be more accurate). I did it out of a sense of security, just like different passwords to different sites. Does having multiple SSH keys actually improve security? All of them are used from the same machine, are located in the same ~/.ssh, most even have the same passphrase. So... should I give up the whole system and just use one SSH key for everything?

  Read the article

• SSH - using keys works, but not in a script

  - by Garfonzo

  I'm kind of confused, I have set up public keys between two servers and it works great, sort of. It only works if I ssh manually from a terminal. When I put the ssh command into a python script, it asks me for a password to login. The script is using rsync to sync up a directory from one server to the other. manual ssh command that works, no password prompt, automatic login: ssh -p 1234 [email protected] In the Python script: rsync --ignore-existing --delete --stats --progress -rp -e "ssh -p 1234" [email protected]:/directory/ /other/directory/ What gives? (obviously, ssh details are fake)

  Read the article

• SSH onto Ubuntu box using RSA keys

  - by jex

  I recently installed OpenSSH on one of my Ubuntu machines and I've been running into problems getting it to use RSA keys. I've generated the RSA key on the client (ssh-keygen), and appended the public key generated to both the /home/jex/.ssh/authorized_keys and /etc/ssh/authorized_keys files on the server. However, when I try to login (ssh -o PreferredAuthorizations=publickey jex@host -v [which forces the use of public key for login]) I get the following output: debug1: Host 'pentheon.local' is known and matches the RSA host key. debug1: Found key in /home/jex/.ssh/known_hosts:2 debug1: ssh_rsa_verify: signature correct debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug1: SSH2_MSG_NEWKEYS received debug1: SSH2_MSG_SERVICE_REQUEST sent debug1: SSH2_MSG_SERVICE_ACCEPT received Banner message debug1: Authentications that can continue: publickey,keyboard-interactive debug1: Next authentication method: publickey debug1: Offering public key: /home/jex/.ssh/id_rsa debug1: Authentications that can continue: publickey,keyboard-interactive debug1: Trying private key: /home/jex/.ssh/identity debug1: Trying private key: /home/jex/.ssh/id_dsa debug1: No more authentication methods to try. Permission denied (publickey,keyboard-interactive). I'm not entirely sure where I've gone wrong. I am willing to post my /etc/ssh/sshd_config if needed.

  Read the article

• Does ssh-copy-id overwrite previous keys?

  - by decker

  I haven't yet found any definitive answer on this using google. It seems like the answer is no, but I need to know for sure before I go ahead and do it. Does ssh-copy-id append the key to authorized_keys or does it overwrite the previous keys? Thanks. Addendum: So the answer is right there in the man page. Go figure. I guess the question can at least help fellow Google-jockeys like me who get a little too used to googling and finding tutorials (that often explain things in layman's terms for us poor folks who have only used Windows our whole lives).

  Read the article

• Foreign Keys and Primary Keys at the same time

  - by Bader

  hello , i am trying to create table (orderdetails) , the table has two FKs and PKs at the same keys here is my code create table OrderDetails2 ( PFOrder_ID Number(3) PFProduct_ID Number(3) CONSTRAINT PF PRIMARY KEY (PFOrder_ID,PFProduct_ID), CONSTRAINT FK_1 FOREIGN KEY (PFProudct_ID) REFERENCES Product(Product_ID), CONSTRAINT FK_2 FOREIGN KEY (PFOrder_ID) REFERENCES Orderr(Order_ID) ); i am using Oracle express , a problem pops when i run the code , here is it ORA-00907: missing right parenthesis what is the problem ?

  Read the article

• Database Design Composite Keys

  - by guazz

  I am going to use a contrived example: one headquarter has one-or-many contacts. A contact can only belong to one headquarter. TableName = Headquarter Column 0 = Id : Guid [PK] Column 1 = Name : nvarchar(100) Column 2 = IsAnotherAttribute: bool TableName = ContactInformation Column 0 = Id : Guid [PK] Column 1 = HeadquarterId: Guid [FK] Column 2 = AddressLine1 COlumn 3 = AddressLine2 Column 4 = AddressLine3 I would like some help setting the table primary keys and foreign keys here? How does the above look? Should I use a composite key for ContactInformation on [Column 0 and Column1]? Is it ok to use surrogate key all of the time?

  Read the article

• SQL Server 2008: The columns in table do not match an existing primary key or unique constraint

  - by 109221793

  Hi guys, I need to make some changes to a SQL Server 2008 database. This requires the creation of a new table, and inserting a foreign key in the new table that references the Primary key of an already existing table. So I want to set up a relationship between my new tblTwo, which references the primary key of tblOne. However when I tried to do this (through SQL Server Management Studio) I got the following error: The columns in table 'tblOne' do not match an existing primary key or UNIQUE constraint I'm not really sure what this means, and I was wondering if there was any way around it?

  Read the article

• Checking for alternate keys with XNA IsKeyDown

  - by jocull

  I'm working on picking up XNA and this was a confusing point for me. KeyboardState keyState = Keyboard.GetState(); if (keyState.IsKeyDown(Keys.Left) || keyState.IsKeyDown(Keys.A)) { //Do stuff... } The book I'm using (Learning XNA 4.0, O'Rielly) says that this method accepts a bitwise OR series of keys, which I think should look like this... KeyboardState keyState = Keyboard.GetState(); if (keyState.IsKeyDown(Keys.Left | Keys.A)) { //Do stuff... } But I can't get it work. I also tried using !IsKeyUp(... | ...) as it said that all keys had to be down for it to be true, but had no luck with that either. Ideas? Thanks.

  Read the article

• Update multiple rows with known keys without inserting new rows if nonexistent keys are found

  - by Kirzilla

  Hello, Let's imagine that we have table items... table: items item_id INT PRIMARY AUTO_INCREMENT title VARCHAR(255) views INT Let's imagine that it is filled with something like (1, item-1, 10), (2, item-2, 10), (3, item-3, 15) I want to make multi update view for this items from data taken from this array [item_id] = [views] '1' => '50', '2' => '60', '3' => '70', '5' => '10' IMPORTANT! Please note that we have item_id=5 in array, but we don't have item_id=5 in database. I can use INSERT ... ON DUPLICATE KEY UPDATE, but this way image_id=5 will be inserted into talbe items. How to avoid inserting new key? I just want item_id=5 be skipped because it is not in table. Of course, before execution I can select existing keys from items table; then compare with keys in array; delete nonexistent keys and perform INSERT ... ON DUPLICATE KEY UPDATE. But maybe there is some more elegant solutions? Thank you.

  Read the article

• Is the location of SSH keys on Windows fixed?

  - by user16654

  I read an article: Determine whether you've already generated SSH keys which says that ssh in Windows, keys are in C:\Documents and Settings\userName\Application Data\SSH\UserKeys\ but I have found the keys to be in C:\Documents and Settings\userName\Application Data.SSH . Is there a setting to determine where to put these keys or am I reading the wrong documentation or what?

  Read the article

• Backup those keys, citizen

  - by BuckWoody

  Periodically I back up the keys within my servers and databases, and when I do, I blog a reminder here. This should be part of your standard backup rotation – the keys should be backed up often enough to have at hand and again when they change. The first key you need to back up is the Service Master Key, which each Instance already has built-in. You do that with the BACKUP SERVICE MASTER KEY command, which you can read more about here. The second set of keys are the Database Master Keys, stored per database, if you’ve created one. You can back those up with the BACKUP MASTER KEY command, which you can read more about here. Finally, you can use the keys to create certificates and other keys – those should also be backed up. Read more about those here. Anyway, the important part here is the backup. Make sure you keep those keys safe! Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

  Read the article

• Is there a canonical source supporting "all-surrogates"?

  - by user61852

  Background The "all-PK-must-be-surrogates" approach is not present in Codd's Relational Model or any SQL Standard (ANSI, ISO or other). Canonical books seems to elude this restrictions too. Oracle's own data dictionary scheme uses natural keys in some tables and surrogate keys in other tables. I mention this because these people must know a thing or two about RDBMS design. PPDM (Professional Petroleum Data Management Association) recommend the same canonical books do: Use surrogate keys as primary keys when: There are no natural or business keys Natural or business keys are bad ( change often ) The value of natural or business key is not known at the time of inserting record Multicolumn natural keys ( usually several FK ) exceed three columns, which makes joins too verbose. Also I have not found canonical source that says natural keys need to be immutable. All I find is that they need to be very estable, i.e need to be changed only in very rare ocassions, if ever. I mention PPDM because these people must know a thing or two about RDBMS design too. The origins of the "all-surrogates" approach seems to come from recommendations from some ORM frameworks. It's true that the approach allows for rapid database modeling by not having to do much business analysis, but at the expense of maintainability and readability of the SQL code. Much prevision is made for something that may or may not happen in the future ( the natural PK changed so we will have to use the RDBMS cascade update funtionality ) at the expense of day-to-day task like having to join more tables in every query and having to write code for importing data between databases, an otherwise very strightfoward procedure (due to the need to avoid PK colisions and having to create stage/equivalence tables beforehand ). Other argument is that indexes based on integers are faster, but that has to be supported with benchmarks. Obviously, long, varying varchars are not good for PK. But indexes based on short, fix-length varchar are almost as fast as integers. The questions - Is there any canonical source that supports the "all-PK-must-be-surrogates" approach ? - Has Codd's relational model been superceded by a newer relational model ?

  Read the article

< Previous Page | 2 3 4 5 6 7 8 9 10 11 12 13  | Next Page >