cons - Page 49 - Developer IT

how to store xml structure in a persistence layer?

- by fayer

i wonder how i could store a xml structure in a persistence layer. cause the relational data looks like: <entity id="1000070"> <name>apple</name> <entities> <entity id="7002870"> <name>mac</name> <entities> <entity id="7002907"> <name>leopard</name> <entities> <entity id="7024080"> <name>safari</name> </entity> <entity id="7024701"> <name>finder</name> </entity> </entities> </entity> </entities> </entity> <entity id="7024080"> <name>iphone</name> <entities> <entity id="7024080"> <name>3g</name> </entity> <entity id="7024701"> <name>3gs</name> </entity> </entities> </entity> <entity id="7024080"> <name>ipad</name> </entity> </entities> </entity> as you can see, it has no static structure but a dynamical one. mac got 2 descendant levels while iphone got 1 and ipad got 0. i wonder how i could store this data the best way? what are my options. cause it seems impossible to store it in a mysql database due to this dynamical structure. is the only way to store it as a xml file then? is the speed of getting information (xpath/xquery/simplexml) from a xml file worse or greater than from mysql? what are the pros and cons? do i have other options? is storing information in xml files, suited for a lot of users accessing it at the same time? would be great with feedbacks!! thanks!

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C++ vs Matlab vs Python as a main language for Computer Vision Research

- by Hough

Hi all, Firstly, sorry for a somewhat long question but I think that many people are in the same situation as me and hopefully they can also gain some benefit from this. I'll be starting my PhD very soon which involves the fields of computer vision, pattern recognition and machine learning. Currently, I'm using opencv (2.1) C++ interface and I especially like its powerful Mat class and the overloaded operations available for matrix and image operations and seamless transformations. I've also tried (and implemented many small vision projects) using opencv python interface (new bindings; opencv 2.1) and I really enjoy python's ability to integrate opencv, numpy, scipy and matplotlib. But recently, I went back to opencv C++ interface because I felt that the official python new bindings were not stable enough and no overloaded operations are available for matrices and images, not to mention the lack of machine learning modules and slow speeds in certain operations. I've also used Matlab extensively in the past and although I've used mex files and other means to speed up the program, I just felt that Matlab's performance was inadequate for real-time vision tasks, be it for fast prototyping or not. When the project becomes larger and larger, many tasks have to be re-written in C and compiled into Mex files increasingly and Matlab becomes nothing more than a glue language. Here comes the sub-questions: For carrying out research in these fields (machine learning, vision, pattern recognition), what is your main or ideal programming language for rapid prototyping of ideas and testing algorithms contained in papers? For computer vision research work, can you list down the pros and cons of using the following languages? C++ (with opencv + gsl + svmlib + other libraries) vs Matlab (with all its toolboxes) vs python (with the imcomplete opencv bindings + numpy + scipy + matplotlib). Are there computer vision PhD/postgrad students here who are using only C++ (with all its availabe libraries including opencv) without even needing to resort to Matlab or python? In other words, given the current existing computer vision or machine learning libraries, is C++ alone sufficient for fast prototyping of ideas? If you're currently using Java or C# for your research, can you list down the reasons why they should be used and how they compare to other languages in terms of available libraries? What is the de facto vision/machine learning programming language and its associated libraries used in your research group? Thanks in advance. Edit: As suggested, I've opened the question to both academic and non-academic computer vision/machine learning/pattern recognition researchers and groups.

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SaaS Architecture Question from Newbie

- by user226767

I have developed a number of departmental client-server applications, and am now ready to begin working on moving one of these applications to a SaaS model. I have done some basic web development, but I'm a newbie when it comes to SaaS architectures. One of the first questions that comes to mind as I try to design the architecture is the question of single vs. multi tenancy. The pros and cons of each vary significantly depending on the type of application and scale required, so I'd like to describe my application and scale needs below, and hope others can comment on how I should get started with the architecture. The client-server application currently consists of a Firebird database and a Windows application. The database contains about 20 tables containing a few thousand records in 4 primary tables, and a few hundred records in various lookup and related tables. Although the number of records is small, the size can get large, as the database can contain large BLOBS. Each customer sets up their own database and has a handful of users within the organization connected to it. When I update the db schema, a new windows application is released, and it checks the db schema and then applies the updates as needed. For the SaaS application, I am designing for 100's (not 1000's or millions) of new customers per year. My first thought was to go with a multi tenancy model to make updates easy (shut down apply the updates to one database, and then start up). On the other hand, a single tenancy model would provide a means to roll updates out to a group of customers at a time, and spread the risk of data corruption - i.e. if something goes wrong with a database, it will impact one customer instead of all customers. With this idea, I was thinking of having a single web front-end which would connect to a single customer database upon login. Thus, when a new customer creates an account, a new database would be created (each customer would have their own db with multiple users as needed for the customer). In this model, a db update would require either a process to go through each db to apply schema changes, or a trigger upon logging in to initiate a schema update similar to the client-server model currently in use. Can anyone point me to information for similar applications which have been ported from client-server to SaaS? Or provide any pointers to consider? Basically I'm looking for architecture examples of taking a departmental application and making it available as a self service website for multiple customers. Thanks for any suggestions, resources, etc.

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Is it ok to use in place of blindly ?

- by metal-gear-solid

Note: I know is presentational and is better way and and for emphasis but my question is not regarding this. Should we convert every to blindly ? many people do this they think is not good as per web standards so they convert every to upon site redesign, content re-population, new site design and people suggest this to others also. Dreamweaver has also given option to convert all and to and on code paste in design view and when we use B and I Which people use blindly. And Dreamweaver(if above option is checked) and many online WYSIWYG editor give output in and while button shows B and I. In my opinion it's creating misconception about and When we get content from client we don't know where client want to give emphasize and where he just want to use text bold for presentation purpose.What we should do in this condition? no one has time client and we both to give time to think for each bold text, it should be in or in , or in What are pros and cons to convert every and into and blindly if we are saying our site is accessible? Update: remember and are not deprecated there are in HTML 5 specification

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How to communicate between Client and Server in a Client-Server Application?

- by Sanoj

I would like to implement an Client-Server Application, where the business-logic, security validations and a database are at the server and the user interface are at the client. I would like to implement clients in different languages i.e. one in WPF/.NET, one Swing/Java , one in Android/Java and maybe one HTML/JavaScript client. The server will be on Internet, so I would like to be able to have encrypted communication. The client will send some lists of items to be added to the database, or update items, and do some transactions. The server will check if the items are already updated by another client, or update the item, add new items or delete items. How do I solve the communication between clients and the server in such a system? I have been thinking about: http/https webserver, and sending messages in JSON or XML and use Web Sockets for bi-directional communication. Use http in a RESTful way, except when WebSockets are needed. But I guess there are better solutions for native desktop applications than http? CORBA - I have just heard about it, and it's old and complex. Not much talk about it these days. XMPP/Jabber - I have just heard about it and I don't know if it fits me at all. EJabberd seams to be a popular implementation. AMQP - I have just heard about it and I don't know if it fits me at all. RabbitMQ seams to be a popular implementation. Windows Communication Foundation, Java RMI, Java Message Service - but are they language independent? I guess some of these alternatives are on different levels, maybe I can have i.e xmpp or amqp in web sockets over https? What technologys are used for this problem in companies today? and what is recommended to use? I have no experience of them other than webservers and http. Please give me some guidance in this jungle. What are the pros and cons of these technologies in my situation?

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IQueryable and lazy loading

- by Nelson

I'm having a hard time determining the best way to handle this... With Entity Framework (and L2S), LINQ queries return IQueryable. I have read various opinions on whether the DAL/BLL should return IQueryable, IEnumerable or IList. Assuming we go with IList, then the query is run immediately and that control is not passed on to the next layer. This makes it easier to unit test, etc. You lose the ability to refine the query at higher levels, but you could simply create another method that allows you to refine the query and still return IList. And there are many more pros/cons. So far so good. Now comes Entity Framework and lazy loading. I am using POCO objects with proxies in .NET 4/VS 2010. In the presentation layer I do: foreach (Order order in bll.GetOrders()) { foreach (OrderLine orderLine in order.OrderLines) { // Do something } } In this case, GetOrders() returns IList so it executes immediately before returning to the PL. But in the next foreach, you have lazy loading which executes multiple SQL queries as it gets all the OrderLines. So basically, the PL is running SQL queries "on demand" in the wrong layer. Is there any sensible way to avoid this? I could turn lazy loading off, but then what's the point of having this "feature" that everyone was complaining EF1 didn't have? And I'll admit it is very useful in many scenarios. So I see several options: Somehow remove all associations in the entities and add methods to return them. This goes against the default EF behavior/code generation and makes it harder to do some composite (multiple entity) LINQ queries. It seems like a step backwards. I vote no. If we have lazy loading anyway which makes it hard to unit test, then go all the way and return IQueryable. You'll have more control farther up the layers. I still don't think this is a good option because IQueryable ties you to L2S, L2E, or your own full implementation of IQueryable. Lazy loading may run queries "on demand", but doesn't tie you to any specific interface. I vote no. Turn off lazy loading. You'll have to handle your associations manually. This could be with eager loading's .Include(). I vote yes in some specific cases. Keep IList and lazy loading. I vote yes in many cases, only due to the troubles with the others. Any other options or suggestions? I haven't found an option that really convinces me.

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What is your most productive shortcut with Vim?

- by Olivier Pons

I've heard a lot about Vim, both pros and cons. It really seems you should be (as a developer) faster with Vim than with any other editor. I'm using Vim to do some basic stuff and I'm at best 10 times less productive with Vim. The only two things you should care about when you talk about speed (you may not care enough about them, but you should) are: Using alternatively left and right hands is the fastest way to use the keyboard. Never touching the mouse is the second way to be as fast as possible. It takes ages for you to move your hand, grab the mouse, move it, and bring it back to the keyboard (and you often have to look at the keyboard to be sure you returned your hand properly to the right place) Here are two examples demonstrating why I'm far less productive with Vim. Copy/Cut & paste. I do it all the time. With all the classical editors you press Shift with the left hand, and you move the cursor with your right hand to select text. Then Ctrl+C copies, you move the cursor and Ctrl+V pastes. With Vim it's horrible: yy to copy one line (you almost never want the whole line!) [number xx]yy to copy xx lines into the buffer. But you never know exactly if you've selected what you wanted. I often have to do [number xx]dd then u to undo! Another example? Search & replace. In PSPad: Ctrl+f then type what you want you search for, then press Enter. In Vim: /, then type what you want to search for, then if there are some special characters put \ before each special character, then press Enter. And everything with Vim is like that: it seems I don't know how to handle it the right way. NB : I've already read the Vim cheat sheet :) My question is: What is the way you use Vim that makes you more productive than with a classical editor?

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General ORM design question

- by Calvin

Suppose you have 2 classes, Person and Rabbit. A person can do a number of things to a rabbit, s/he can either feed it, buy it and become its owner, or give it away. A rabbit can have none or at most 1 owner at a time. And if it is not fed for a while, it may die. Class Person { Void Feed(Rabbit r); Void Buy(Rabbit r); Void Giveaway(Person p, Rabbit r); Rabbit[] rabbits; } Class Rabbit { Bool IsAlive(); Person pwner; } There are a couple of observations from the domain model: Person and Rabbit can have references to each other Any actions on 1 object can also change the state of the other object Even if no explicit actions are invoked, there can still be a change of state in the objects (e.g. Rabbit can be starved to death, and that causes it to be removed from the Person.rabbits array) As DDD is concerned, I think the correct approach is to synchronize all calls that may change the states in the domain model. For instance, if a Person buys a Rabbit, s/he would need to acquire a lock in Person to make a change to the rabbits array AND also another lock in Rabbit to change its owner before releasing the first one. This would prevent a race condition where 2 Persons claim to be the owner of the little Rabbit. The other approach is to let the database to handle all these synchronizations. Who makes the first call wins, but then the DB needs to have some kind of business logics to figure out if it is a valid transaction (e.g. if a Rabbit already has an owner, it cannot change its owner unless the Person gives it away). There are both pros/cons in either approach, and I’d expect the “best” solution would be somewhere in-between. How would you do it in real life? What’s your take and experience? Also, is it a valid concern that there can be another race condition the domain model has committed its change but before it is fully committed in the database? And for the 3rd observation (i.e. state change due to time factor). How will you do it?

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Anyone have experience calling Rake from MSBuild for code gen and other benefits? How did it go? Wha

- by Charlie Flowers

While programming in C# using Visual Studio 2008, I often wish for "automatic" code generation. If possible, I'd like to achieve it by making my MSBuild solution file call out to Rake, which would call Ruby code for the code generation, having the resulting generated files automatically appear in my solution. Here's one business example (of many possible examples I could name) where this kind of automatic code generation would be helpful. In a recent project I had an interface with some properties that contained dollar amounts. I wanted a second interface and a third interface that had the same properties as the first interface, except they were "qualified" with a business unit name. Something like this: public interface IQuarterlyResults { double TotalRevenue { get; set; } double NetProfit { get; set; } } public interface IConsumerQuarterlyResults { double ConsumerTotalRevenue { get; set; } double ConsumerNetProfit { get; set; } } public interface ICorporateQuarterResults { double CorporateTotalRevenue { get; set; } double CorporateNetProfit { get; set; } } In this example, there is a "Consumer Business Unit" and a "Corporate Business Unit". Every property on IQuarterlyResults becomes a property called "Corporate" + [property name] on ICorporateQuarterlyResults, and likewise for IConsumerQuarterlyResults. Why make interfaces for these, rather than merely having an instance of IQuarterlyResults for Consumer and another instance for Corporate? Because, when working with the calculator object I was building, the user had to deal with 100's of properties, and it is much less confusing if he can deal with "fully qualified" property names such as "ConsumerNetProfit". But let's not get bogged down in this example. It is only an example and not the main question. The main question is this: I love using Ruby and ERB for code generation, and I love using Rake to manage dependencies between tasks. To solve the problem above, what I'd like to do is have MSBuild call out to Rake, and have Rake / Ruby read the list of properties on the "core" interface and then generate the code to make all the dependent interfaces and their properties. This would get triggered every time I do a build, because I'd put it into the MSBuild file for the VS.NET solution. Has anyone tried anything like this? How did it work out for you? What insights can you share about pros, cons, tips for success, etc.? Thanks!

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Best practices regarding equals: to overload or not to overload?

- by polygenelubricants

Consider the following snippet: import java.util.*; public class EqualsOverload { public static void main(String[] args) { class Thing { final int x; Thing(int x) { this.x = x; } public int hashCode() { return x; } public boolean equals(Thing other) { return this.x == other.x; } } List<Thing> myThings = Arrays.asList(new Thing(42)); System.out.println(myThings.contains(new Thing(42))); // prints "false" } } Note that contains returns false!!! We seems to have lost our things!! The bug, of course, is the fact that we've accidentally overloaded, instead of overridden, Object.equals(Object). If we had written class Thing as follows instead, then contains returns true as expected. class Thing { final int x; Thing(int x) { this.x = x; } public int hashCode() { return x; } @Override public boolean equals(Object o) { return (o instanceof Thing) && (this.x == ((Thing) o).x); } } Effective Java 2nd Edition, Item 36: Consistently use the Override annotation, uses essentially the same argument to recommend that @Override should be used consistently. This advice is good, of course, for if we had tried to declare @Override equals(Thing other) in the first snippet, our friendly little compiler would immediately point out our silly little mistake, since it's an overload, not an override. What the book doesn't specifically cover, however, is whether overloading equals is a good idea to begin with. Essentially, there are 3 situations: Overload only, no override -- ALMOST CERTAINLY WRONG! This is essentially the first snippet above Override only (no overload) -- one way to fix This is essentially the second snippet above Overload and override combo -- another way to fix The 3rd situation is illustrated by the following snippet: class Thing { final int x; Thing(int x) { this.x = x; } public int hashCode() { return x; } public boolean equals(Thing other) { return this.x == other.x; } @Override public boolean equals(Object o) { return (o instanceof Thing) && (this.equals((Thing) o)); } } Here, even though we now have 2 equals method, there is still one equality logic, and it's located in the overload. The @Override simply delegates to the overload. So the questions are: What are the pros and cons of "override only" vs "overload & override combo"? Is there a justification for overloading equals, or is this almost certainly a bad practice?

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how to design this relation in a DB schema

- by raticulin

I have a table Car in my db, one of the columns is purchaseDate. I want to be able to tag every car with a number of Policies (limited to 10 policies). Each policy has a time to life (ttl, a duration of time, like '5 years', '10 months' etc), that is, for how long since the car's purchaseDate the policy can be applied. I need to perform the following actions: when inserting a Car, it will be set with a number of Policies (at least one is set) sometimes a Car will be updated to add/remove a Policy searches must be done taking into account date/policies, for example: 'select all cars that are not covered by any policy as of today' My current design is (pol0..pol9 are the policies): CREATE TABLE Car ( id int NOT NULL IDENTITY(1,1), purchaseDate datetime NOT NULL, //more stuff... pol0 smallint default NULL, pol1 smallint default NULL, pol2 smallint default NULL, pol3 smallint default NULL, pol4 smallint default NULL, pol5 smallint default NULL, pol6 smallint default NULL, pol7 smallint default NULL, pol8 smallint default NULL, pol9 smallint default NULL, PRIMARY KEY (id) ) CREATE TABLE Policy ( id smallint NOT NULL, name varchar(50) collate Latin1_General_BIN NOT NULL, ttl varchar(100) collate Latin1_General_BIN NOT NULL, PRIMARY KEY (id) ) The problem I am facing is that the sql to perform the query above is a nightmare to write. As I don't know in which column each policy can be, so I have to check all columns for every policy etc etc. So I am wondering wether it is worth changing this. My questions are: The smallint as Policy id was chosen instead of an 'int IDENTITY' in order to save some space as there are going to be millions of Car records. It just adds complexity when creating a Policy as we must handle the id etc. Was it worth doing this? I am thinking that maybe there is a much better design? Obviously we could move the policy/car relation to its own table CarPolicy, benefits would be: no limit on 10 policies per car adding/removing etc much easier when only the default policy is applied (when no others are applied one called Default policy is applied), we could signal that by not having any entry in CarPolicy, now this is just done inserting the Default policy id in one of the columns. The cons are that we would need to change the DB, ORM classes etc. What would you recommend? Maybe there is another smart way to implement this that we are not aware without using the CarPolicy table?

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drupal (CMS) or codeigniter (MVC) for creating a new web application?

- by ajsie

im going to create a new web application that is very customized. it will contain images, that are fully searchable - in a very, very customized way. when you click on the pictures you can add comments and so on. it requires users to be registered, but the registration/login process will be highly customized too. at the moment im using CodeIgniter for this. But i've read a lot of posts about CMS like Drupal and it sounds like i could let it handle basic stuff, maybe design and other front end work. i have no experience with CMS, in fact, i just started to use a MVC framework like CI and was impressed of how much easier it gets to start developing. so i wonder, if i'm going to create this kind of application, could i use drupal and then add the usual stuff, as i was going to do with CodeIgniter, like controllers, views, models, config files, my own libraries and so on? how does it work on a system like Drupal. how do you code PHP with it as with any MVC framework. it sounds like it has a lot of modules, i just wonder, if i can use it as a MVC framework but have the benefit of having all these basic stuff and design ready to use? cause then it sounds like the best "library" to provide for a web application from scratch. or is it difficult to create a customized app with it? i guess it has modules like images and users, but then how could i customize these so that every image has tags on it and country information, or have every user subscribing to changes to an image, that email will be sent to users and so on? cause i guess its easy to install a module. the question is, how do i customize it. maybe i don't need all that table columns. maybe i want to add/remove business logic. what are the pros and cons with using Drupal for this? is it even the right way to go? can you make a Stackoverflow with Drupal? Facebook? Twitter? Youtube? assuming that you know php of course. share your thoughts cause im totally new on creating a web application! thanks

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urgent..haskell mini interpreter

- by mohamed elshikh

i'm asked to implement this project and i have problems in part b which is the eval function this is the full describtion of the project You are required to implement an interpreter for mini-Haskell language. An interpreter is dened in Wikipedia as a computer program that executes, i.e. performs, instructions written in a programming language. The interpreter should be able to evaluate functions written in a special notation, which you will dene. A function is dened by: Function name Input Parameters : dened as a list of variables. The body of the function. The body of the function can be any of the following statements: a) Variable: The function may return any of the input variables. b) Arithmetic Expressions: The arithmetic expressions include input variables and addition, sub- traction, multiplication, division and modulus operations on arithmetic expressions. c) Boolean Expressions: The Boolean expressions include the ordering of arithmetic expressions (applying the relationships: <, =<, , = or =) and the anding, oring and negation of Boolean expressions. d) If-then-else statements: where the if keyword is followed by a Boolean expression. The then and else parts may be followed by any of the statements described here. e) Guarded expressions: where each case consists of a boolean expression and any of the statements described here. The expression consists of any number of cases. The rst case whose condition is true, its body should be evaluated. The guarded expression has to terminate with an otherwise case. f) Function calls: the body of the function may have a call to another function. Note that all inputs passed to the function will be of type Int. The output of the function can be of type Int or Bool. To implement the interpreter, you are required to implement the following: a) Dene a datatype for the following expressions: Variables Arithmetic expressions Boolean expressions If-then-else statements Guarded expressions Functions b) Implement the function eval which evaluates a function. It takes 3 inputs: The name of a function to be evaluated represented as a string. A list of inputs to that function. The arguments will always be of datatype Int. A list of functions. Each function is represented as instance of the datatype that you have created for functions. c) Implement the function get_type that returns the type of the function (as a string). The input to this function is the same as in part b. here is what i've done data Variable = v(char) data Arth= va Variable | Add Arth Arth | Sub Arth Arth | Times Arth Arth | Divide Arth Arth data Bol= Great Arth Arth | Small Arth Arth | Geq Arth Arth | Seq Arth Arth | And Bol Bol | Or Bol Bol | Neg Bol data Cond = data Guard = data Fun =cons String [Variable] Body data Body= bodycons(String) |Bol |Cond |Guard |Arth

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Haskell type classes and type families (cont'd)

- by Giuseppe Maggiore

I need some help in figuring a compiler error which is really driving me nuts... I have the following type class: infixl 7 --> class Selectable a s b where type Res a s b :: * (-->) :: (CNum n) => (Reference s a) -> (n,(a->b),(a->b->a)) -> Res a s b which I instance twice. First time goes like a charm: instance Selectable a s b where type Res a s b = Reference s b (-->) (Reference get set) (_,read,write) = (Reference (\s -> let (v,s') = get s in (read v,s')) (\s -> \x -> let (v,s') = get s v' = write v x (_,s'') = set s' v' in (x,s''))) since the type checker infers (-->) :: Reference s a -> (n,a->b,a->b->a) -> Reference s b and this signature matches with the class signature for (--) since Res a s b = Reference s b Now I add a second instance and everything breaks: instance (Recursive a, Rec a ~ reca) => Selectable a s (Method reca b c) where type Res a s (Method reca b c) = b -> Reference s c (-->) (Reference get set) (_,read,write) = \(x :: b) -> from_constant( Constant(\(s :: s)-> let (v,s') = get s :: (a,s) m = read v ry = m x :: Reference (reca) c (y,v') = getter ry (cons v) :: (c,reca) v'' = elim v' (_,s'') = set s' v'' in (y,s''))) :: Reference s c the compiler complains that Couldn't match expected type `Res a s (Method reca b c)' against inferred type `b -> Reference s c' The lambda expression `\ (x :: b) -> ...' has one argument, which does not match its type In the expression: \ (x :: b) -> from_constant (Constant (\ (s :: s) -> let ... in ...)) :: Reference s c In the definition of `-->': --> (Reference get set) (_, read, write) = \ (x :: b) -> from_constant (Constant (\ (s :: s) -> ...)) :: Reference s c reading carefully the compiler is telling me that it has inferred the type of (--) thusly: (-->) :: Reference s a -> (n,a->(Method reca b c),a->(Method reca b c)->a) -> (b -> Reference s c) which is correct since Res a s (Method reca b c) = b -> Reference s c but why can't it match the two definitions? Sorry for not offering a more succint and standalone example, but in this case I cannot figure how to do it...

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Circular database relationships. Good, Bad, Exceptions?

- by jim

I have been putting off developing this part of my app for sometime purely because I want to do this in a circular way but get the feeling its a bad idea from what I remember my lecturers telling me back in school. I have a design for an order system, ignoring the everything that doesn't pertain to this example I'm left with: CreditCard Customer Order I want it so that, Customers can have credit cards (0-n) Customers have orders (1-n) Orders have one customer(1-1) Orders have one credit card(1-1) Credit cards can have one customer(1-1) (unique ids so we can ignore uniqueness of cc number, husband/wife may share cc instances ect) Basically the last part is where the issue shows up, sometimes credit cards are declined and they wish to use a different one, this needs to update which their 'current' card is but this can only change the current card used for that order, not the other orders the customer may have on disk. Effectively this creates a circular design between the three tables. Possible solutions: Either Create the circular design, give references: cc ref to order, customer ref to cc customer ref to order or customer ref to cc customer ref to order create new table that references all three table ids and put unique on the order so that only one cc may be current to that order at any time Essentially both model the same design but translate differently, I am liking the latter option best at this point in time because it seems less circular and more central. (If that even makes sense) My questions are, What if any are the pros and cons of each? What is the pitfalls of circular relationships/dependancies? Is this a valid exception to the rule? Is there any reason I should pick the former over the latter? Thanks and let me know if there is anything you need clarified/explained. --Update/Edit-- I have noticed an error in the requirements I stated. Basically dropped the ball when trying to simplify things for SO. There is another table there for Payments which adds another layer. The catch, Orders can have multiple payments, with the possibility of using different credit cards. (if you really want to know even other forms of payment). Stating this here because I think the underlying issue is still the same and this only really adds another layer of complexity.

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PHP Shared Sessions across Domain

- by bigstylee

Hi, I have seen a few answers to this on SOO but most of these are concerned with the use of subdomains, of which none have worked for me. The common one being that the use of session.cookie_domain, which from my understanding will only work with subdomains. I am interested in a solution that deals with deals with entirely different domains (and includes the possibility of subdomains). Unfortunately project deadlines being what they are, time is not on my side, so I turn to SOO's expertise and experience. The current project brief is to be able to log into one site which currently only stores the user_id in the session and then be able to retrieve this value while on a different domain within the same server enviroment. Session data is being stored/retrieved from a database where the session id is the primary key. I am hoping to find a "light wieght" and "easy" to implement solution. The system is utlising an in-house Model View Controller design pattern, so all requests (including different domains) are run through a single bootstrap script. Using the domain name as a variable, this determines what context to display to the user. One option that did look like to have potential is the use of a hidden image and using the alt tag to set the user id. My first impressions suggest this immediately seems "too easy" (if possible) and riddled with security flaws. Disscuss? Another option which I considered is using the IP and User Agent for authentication but again I feel this not going to be a reliable option due to shared networks and changing IP addresses. My third option (and preferred) which I considered and as yet not seen discussed is using htaccess to fool the user into thinking that they are on a different domain when infact apache is redirecting; something like www.foo.com/index.php?domain=bar.com&controller=news/categoires/1 but displays to the user as www.bar.com/news/categories/1 foo.com represents the "main site domain" which all requests are run through and bar.com is what the user thinks they are accessing. The controller request dictates the page and view being requested. Is this possible? Are there other options? Pros/Cons? Thanks in advanced!!!

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OFM 11g: OAM SSO for Forms and ADF Faces

- by olaf.heimburger

In my blog entry OFM 11g: Implementing OAM SSO with Forms we set the foundation for providing a complete Single Sign-On solution based on Oracle Access Manager (OAM). This foundation should now be used to combine Forms 11g and ADF Faces 11g applications with a transparent login. The Beginning Before we start, lets re-consider the requirements to achieve the ultimate goal. These are:- Access to the Forms 11g Application must be authenticated by OAM (protected). Access to the ADF Faces 11g Application must be authenticated by OAM (protected). Switching from one application to the other should not result in a re-authentication (aka single sign-on). User identity should be availble to the application without any extra work in the application code. All these are the common requirements for a single sign-on solution. The challenge here is that Forms relies on Oracle AS SSO (OSSO or "the old SSO") while ADF Faces is quite open and can be protected by Oracle AS SSO and Oracle Access Manager SSO (OAM SSO or "the modern SSO"). Both application types can use their own login mechanism. The Forms 11g Application To demonstrate the SSO functionality, we use the standard Forms test (/forms/frmservlet?form=test.fmx). Although this shows nothing specific in the Forms application, it is good enough to demonstrate that it is protected. The ADF Faces 11g Application With ADF 11g you can develop quite a number of useful Faces based applications. Among many features, it comes with the ADF Security feature that provides you with functionality to protect your pages, regions, and even TaskFlows from un-authenticated usage in a declarative way.To demonstrate that functionality a sample application with different access levels plus a login dialog is used. This application comes with a publc page that has protected content (a button). Once you are authenticated for the application, the protected content and some personalisation (the users name) is shown. Protecting Forms 11g As already explained in the OFM 11g: Implementing OAM SSO with Forms, the easiest way to protect a Forms application is to configure it as a OSSO partner application, setup mod_osso, test it, migrate OSSO to OAM SSO with the Upgrade Agent, reconfigure mod_osso, and you are done.Sort of. By default the OAM is configured to run in co-exist mode. This means that a user has to re-authenticate to the Forms application when logged into an OAM SSO application before. To avoid this, you must disable the co-exist mode, for example by using WLST and issue the disableCoexistMode on the OAM server. Protecting ADF Faces 11g To protect an ADF Faces 11g application we have to consider two scenarios: Use a HTTPD server in front of WLS Use WLS without a HTTPD server Both scenarios have their pro's and cons' and we won't get into details and just describe how to configure both. Scenario 1: HTTPD Server with WLS In this scenario we have to setup the environment in some steps:- Configure a WebGate at OAMThis configuration can be done through the OAM console or by a script. No matter which way you choose, the WebGate configuration files will be created for you. Install the OAM WebGate into an HTTPD serverThe type of webgate you need to install depends on you HTTPD server. With Oracle HTTP Server 11g you can use the latest OAM 11g WebGate. With other HTTPD servers you must resort to OAM 10g WebGates. A OAM 11g WebGate can use the pre-created configuration files supplied during the WebGate configuration at OAM. An OAM 10g WebGate asks for the specific configuration and verifies it during installation. Configure the WLS plugin to forward the requests to WLSAgain, depending on your HTTPD Server you have different plugins to forward requests to WLS. With OHS 11g you can use the pre-installed mod_wl_ohs plugin. Its configuration is quite simple and straightforward. Configure an OAM SSPI Provider as a IdentityAsserter in WLS to retrieve the user identifierThis configuration is quite important as it retrieves the user identifier for the next step. If you have a SOA Suite installation within your OFM_HOME, the necessary software is already installed and you only need to setup your Security Realm within WLS.You can do this by pointing your browser to the WLS Console, log in as administrator, select the Security Realm (usually myrealm), and select Providers. We add the OAMIdentityAsserter as the first SSPI Provider. It is important that the Control Flag is set to SUFFICIENT. Every other configuration can be left as is, no changes are necessary here. Configure an OAM Identity Provider to get the real user identityIn OFM 11g: Implementing OAM SSO with Forms we have configured an OID as Identity Store. To get the user identity we need to configure the same OID as an SSPI Provider for WLS. This will retrieve the real user information from OID and creates the JAAS Subject and Principals to be used by any application within WLS.Again, you can do this by pointing your browser to the WLS Console, log in as administrator, select the Security Realm (usually myrealm), and select Providers. Now add the OIDAuthenticator as the second SSPI Provider. It is important that the Control Flag is set to OPTIONAL. After we saved this setup, we need to configure this provider by setting the Provider Specific details to access OID. Scenario 2: WLS only This scenario is a bit easier but requires more work in the WLS setup:- Configure a WebGate at OAMThis configuration can be done through the OAM console or by a script. No matter which way you choose, the WebGate configuration files will be created for you. Configure the OAM SSPI Provider as IdentityAuthenticator to authenticate and set the user identifierWhen using the OAM SSPI Provider as OAMAuthenticator we create it with the Control Flag as SUFFICIENT. Afte saving it, the Provider Specific settings must be configured to allow the OAM SSPI Provider to connect to the OAM Server. Configure an OAM Identity Provider to get the real user identity providerAgain, you can do this by pointing your browser to the WLS Console, log in as administrator, select the Security Realm (usually myrealm), and select Providers. Now add the OIDAuthenticator as the second SSPI Provider. It is important that the Control Flag is set to OPTIONAL. After we saved this setup, we need to configure this provider by setting the Provider Specific details to access OID. Configure ADF 11g Application for OAM Actually, there are no changes to be made within the ADF application. We only need to add the value CLIENT_CERT to the <auth-mode> tag in the <login-config> tag in the web.xml file. Testing To test the configuration, simply point your browser to one of both appliction URLs. OAM should kick in and redirect you to the OAM Login page. After you have entered the correct credentials, access to the URLs is granted and you will see the application. Enjoy!

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IIS7 web farm - local or shared content?

- by rbeier

We're setting up an IIS7 web farm with two servers. Should each server have its own local copy of the content, or should they pull content directly from a UNC share? What are the pros and cons of each approach? We currently have a single live server WEB1, with content stored locally on a separate partition. A job periodically syncs WEB1 to a standby server WEB2, using robocopy for content and msdeploy for config. If WEB1 goes down, Nagios notifies us, and we manually run a script to move the IP addresses to WEB2's network interface. Both servers are actually VMs running on separate VMWare ESX 4 hosts. The servers are domain-joined. We have around 50-60 live sites on WEB1 - mostly ASP.NET, with a few that are just static HTML. Most are low-traffic "microsites". A few have moderate traffic, but none are massive. We'd like to change this so both WEB1 and WEB2 are actively serving content. This is mainly for reliability - if WEB1 goes down, we don't want to have to manually intervene to fail things over. Spreading the load is also nice, but the load is not high enough right now for us to need this. We're planning to configure our firewall to balance traffic across the two servers. It will detect when a server goes down and will send all the traffic to the remaining live server. We're planning to use sticky sessions for now... eventually we may move to SQL Server session state and stateless load balancing. But we need a way for the servers to share content. We were originally planning to move all the content to a UNC share. Our storage provider says they can set up a highly available SMB share for us. So if we go the UNC route, the storage shouldn't be a single point of failure. But we're wondering about the downsides to this approach: We'll need to change the physical paths for each site and virtual directory. There are also some projects that have absolute paths in their web.config files - we'll have to update those as well. We'll need to create a domain user for the web servers to access the share, and grant that user appropriate permissions. I haven't looked into this yet - I'm not sure if the application pool identity needs to be changed to this user, or if there's another way to tell IIS to use this account when connecting to the share. Sites will no longer be able to access their content if there's ever an Active Directory problem. In general, it just seems a lot more complicated, with more moving parts that could break. Our storage provider would create a volume for us on their redundant SAN. If I understand correctly, this SAN volume would be mounted on a VM running in their redundant VMWare environment; this VM would then expose the SMB share to our web servers. On the other hand, a benefit of the shared content approach is that we'd only need to deploy code to one place, and there would never be a temporary inconsistency between multiple copies of the content. This thread is pretty interesting, though some of these people are working at a much larger scale. I've just been discussing content so far, but we also need to think about configuration. I don't know if we can just use DFS replication for the applicationHost.config and other files, or if it's best to use the shared configuration feature with the config on a UNC share. What do you think? Thanks for your help, Richard

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SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Introduction – Day 1 of 31

- by pinaldave

List of all the Interview Questions and Answers Series blogs Posts covering interview questions and answers always make for interesting reading. Some people like the subject for their helpful hints and thought provoking subject, and others dislike these posts because they feel it is nothing more than cheating. I’d like to discuss the pros and cons of a Question and Answer format here. Interview Questions and Answers are Helpful Just like blog posts, books, and articles, interview Question and Answer discussions are learning material. The popular Dummy’s books or Idiots Guides are not only for “dummies,” but can help everyone relearn the fundamentals. Question and Answer discussions can serve the same purpose. You could call this SQL Server Fundamentals or SQL Server 101. I have administrated hundreds of interviews during my career and I have noticed that sometimes an interviewee with several years of experience lacks an understanding of the fundamentals. These individuals have been in the industry for so long, usually working on a very specific project, that the ABCs of the business have slipped their mind. Or, when a college graduate is looking to get into the industry, he is not expected to have experience since he is just graduated. However, the new grad is expected to have an understanding of fundamentals and theory. Sometimes after the stress of final exams and graduation, it can be difficult to remember the correct answers to interview questions, though. An interview Question and Answer discussion can be very helpful to both these individuals. It is simply a way to go back over the building blocks of a topic. Many times a simple review like this will help “jog” your memory, and all those previously-memorized facts will come flooding back to you. It is not a way to re-learn a topic, but a way to remind yourself of what you already know. A Question and Answer discussion can also be a way to go over old topics in a more interesting manner. Especially if you have been working in the industry, or taking lots of classes on the topic, everything you read can sound like a repeat of what you already know. Going over a topic in a new format can make the material seem fresh and interesting. And an interested mind will be more engaged and remember more in the end. Interview Questions and Answers are Harmful A common argument against a Question and Answer discussion is that it will give someone a “cheat sheet.” A new guy with relatively little experience can read the interview questions and answers, and then memorize them. When an interviewer asks him the same questions, he will repeat the answers and get the job. Honestly, is he good hire because he memorized the interview questions? Wouldn’t it be better for the interviewer to hire someone with actual experience? The answer is not as easy as it seems – there are many different factors to be considered. If the interviewer is asking fundamentals-related questions only, he gets the answers he wants to hear, and then hires this first candidate – there is a good chance that he is hiring based on personality rather than experience. If the interviewer is smart he will ask deeper questions, have more than one person on the interview team, and interview a variety of candidates. If one interviewee happens to memorize some answers, it usually doesn’t mean he will automatically get the job at the expense of more qualified candidates. Another argument against interview Question and Answers is that it will give candidates a false sense of confidence, and that they will appear more qualified than they are. Well, if that is true, it will not last after the first interview when the candidate is asked difficult questions and he cannot find the answers in the list of interview Questions and Answers. Besides, confidence is one of the best things to walk into an interview with! In today’s competitive job market, there are often hundreds of candidates applying for the same position. With so many applicants to choose from, interviewers must make decisions about who to call back and who to hire based on their gut feeling. One drawback to reading an interview Question and Answer article is that you might sound very boring in your interview – saying the same thing as every single candidate, and parroting answers that sound like someone else wrote them for you – because they did. However, it is definitely better to go to an interview prepared, just make sure that you give a lot of thought to your answers to make them sound like your own voice. Remember that you will be hired based on your skills as well as your personality, so don’t think that having all the right answers will make get you hired. A good interviewee will be prepared, confident, and know how to stand out. My Opinion A list of interview Questions and Answers is really helpful as a refresher or for beginners. To really ace an interview, one needs to have real-world, hands-on experience with SQL Server as well. Interview questions just serve as a starter or easy read for experienced professionals. When I have to learn new technology, I often search online for interview questions and get an idea about the breadth and depth of the technology. Next Action I am going to write about interview Questions and Answers for next 30 days. I have previously written a series of interview questions and answers; now I have re-written them keeping the latest version of SQL Server and current industry progress in mind. If you have faced interesting interview questions or situations, please write to me and I will publish them as a guest post. If you want me to add few more details, leave a comment and I will make sure that I do my best to accommodate. Tomorrow we will start the interview Questions and Answers series, with a few interesting stories, best practices and guest posts. We will have a prize give-away and other awards when the series ends. List of all the Interview Questions and Answers Series blogs Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Interview Questions and Answers, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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Top tweets SOA Partner Community – October 2012

- by JuergenKress

Send your tweets @soacommunity #soacommunity and follow us at http://twitter.com/soacommunity SOA Community Deploying Fusion Order Demo on 11.1.1.6 by Antony Reynolds http://wp.me/p10C8u-vA leonsmiers ?Cant wait to test it >> 't waiRT @OracleSOA: Case Management patterns, session coverage from #OOW #OracleBPM #ACM #BPM http://bit.ly/OdcZL6 Danilo Schmiedel Bye bye San Francisco. #oow was a great conference in a wonderful city! Thanks! @soacommunity pic.twitter.com/lcYSe9xC OPITZ CONSULTING ?The Journey towards #Oracle #BPM @OpenWorld 2012 - Slides by @t_winterberg & H. Normann: http://ow.ly/edkWE #oow demed Full house at the SOA Customer Advisory Board! #oow12 http://instagr.am/p/QX9B8eLMLS/ Danilo Schmiedel "@whitehorsesnl: Had some great talks with the BPM guys at the DEMOgrounds. It is one of the best things at #oow" -> I agree!! @soacommunity Mark Simpson ?Fusion Middleware Global Innovation Awards: nice to pick up a soa and bpm with our customer. #oow Mark Simpson ?RT @SOASimone: #oraclesoa #oow hands on lab fully booked pic.twitter.com/pwI94Ew7 <--quick, provision some more compute power on the cloud! Oracle SOA ?Join us for BPM and Analytics: Process Dashboards. BAM, and Intelligent OptimizationMoscone South - 308#OracleBPM #OOW Oracle SOA ?Real-time public safety demo! License plate recognition and processing in London via Oracle Event Processing. #oow pic.twitter.com/WufesDBq Marc ?Nice session on customer success stories on #SOA11g on with @SOASimone Pro and cons and architectural overview. #oow pic.twitter.com/bzuhsujm Lucas Jellema Full length Keynote on Middleware #oow : http://medianetwork.oracle.com/video/player/1873556035001 … #oow_amis OracleBlogs ?Why Fusion Middleware matters to Oracle Applications and Fusion Applications customers? http://ow.ly/2stVQ0 OracleBlogs ?Open World Session - BPM, SOA and ADF Combined:Patterns learned from Fusion Applications http://ow.ly/2suhzf Ronald Luttikhuizen ?VENNSTER BLOG | Presentations at OpenWorld 2012 | http://blog.vennster.nl/2012/10/presentations-at-openworld-2012.html … Andrejus Baranovskis @dschmied @soacommunity next OOW for sure, and may be SOA community event ! @soacommunity Danilo Schmiedel ?@andrejusb Thanks Andrejus - I really enjoyed having a session with you at #oow. When is next time :-) ? @soacommunity Lionel Dubreuil ?@soacommunity #oow12 Today-1:15pm-Marriott Marquis Salon 7 Jump-starting Integration with Oracle Foundation Pack http://bit.ly/QKKJzF Ronald Luttikhuizen ?Impression from our fault handling session in OSB and SOA Suite from the audience @soacommunity @gschmutz #oow pic.twitter.com/WSg1Z89E Marc Nice session on Oracle Virtual Assembly for #SOA11g, @soacommunity Works with #exalogic but not required SOA Community ?Send your #soacommunity #oow pictures and blog posts @soacommunity or http://www.facebook.com/soacommunity Enjoy OOW ;-) Jon petter hjulstad Oracle BPM- Big leap forward in 11.1.1.7 ! Whitehorses ?Common BPM Use Cases from Oracle #bpm #oow pic.twitter.com/ofOv04EF Whitehorses ?Oracle BPM 11.1.1.7 top new features. Interesting #oow #oowbenelux pic.twitter.com/HY9QN5un SOA Community Industrialized SOA - topic of Business Technology Magazine http://wp.me/p10C8u-vi orclateamsoa ?A-Team Blog #ateam: The curious case of SOA Human tasks' automatic completion http://ow.ly/1mq6YU Simone Geib Look for this sign #oow #oraclesoa pic.twitter.com/MJsPV4PO Lucas Jellema My summary of Larry Ellison's keynote at #oow on the AMIS Blog: http://technology.amis.nl/2012/10/01/oow-2012-larry-ellisons-keynote-announcements-exa-cloud-database/ … #oow_amis gschmutz ?Join my #oow session "Five Cool Use Cases for the Spring Component" to see the power of Spring and SOA Suite combined! Moscone 310 - 3:15 PM Ronald Luttikhuizen Thanks to @soacommunity for great SOA/BPM dinner event yesterday night! #oow pic.twitter.com/v7x3i0DC OracleBlogs ?OSB, Service Callouts and OQL http://ow.ly/2sq6B2 OracleBlogs ?Cloud and On-Premises Applications Integration using Oracle Integration Adapters http://ow.ly/2sqiDy OracleBlogs ?Adapters, SOA Suite and More @Openworld 2012 http://ow.ly/2srdTg Eric Elzinga ?OSB, Service Callouts and OQL - Part 3, http://see.sc/JodzEx #oracleservicebus Donatas Valys interesting articles about soa industrialization to read #soa #industrialization http://it-republik.de/business-technology/bt-magazin-ausgaben/Industrialized-SOA-000516.html … gschmutz ?“@techsymp: 2012 Symposium Presentation Download Page Now Available! 75% of presentations published. http://www.servicetechsymposium.com ” find mine there.. Oracle BPM Customer Experience and BPM – From Efficiency to Engagement #bpm #oraclebpm #processmanagement #socialbpm http://pub.vitrue.com/Tahi SOA Community ?@soacommunity SOA Community Newsletter September 2012 http://wp.me/p10C8u-wa SOA Community again again again.... it is Oracle Open World 2012 http://wp.me/p10C8u-wk OracleBlogs ?SOA Proactive support http://ow.ly/2smrSJ demed ?@gschmutz on NoSQL at @techsymp http://lockerz.com/s/247601661 demed ?Just finished "#BigData and its impact on #SOA" talk @techsymp. Really enjoyed getting out of beaten path. #london #oep http://lockerz.com/s/247636974 OTNArchBeat ?Need help selling SOA to business stakeholders? Give them this free eBook. #soasuite http://pub.vitrue.com/hsQY SOA Community top Tweets SOA Partner Community – September 2012 http://wp.me/p10C8u-vc SOA Community Move Data into the grid for scalable, predictable response times http://wp.me/p10C8u-vv ServiceTechSymposium ?The September issue of the Service Technology Magazine is now published with six new items! Read them at http://www.servicetechmag.com Marc ?Reviewed @Packt_OracleFMW new book on SOA11g administration! Very good ! http://tinyurl.com/8pzd5ww SOA Community ?BPM Solution Catalogue–promote your process templates http://wp.me/p10C8u-vt OTNArchBeat ?BPM ADF Task forms: Checking whether the current user is in a BPM Swimlane | @ChrisKarlChan http://pub.vitrue.com/aPMG OTNArchBeat ?Cloud, automation drive new growth in SOA governance market | @JoeMcKendrick http://pub.vitrue.com/hNPv Simon Haslam ?Looking for "oak style"(!) advanced content but you're a middleware specialist? See #ukoug2012 #middlewaresunday http://2012.ukoug.org/default.asp?p=9355 … Simon Haslam ?The #ukoug2012 agenda is "go, go, go!" (as Murray would say!) http://2012.ukoug.org/agendagrid Germán Gazzoni SOA Spezial II verfügbar – Industralized SOA: Die überarbeitete und ergänzte Neuauflage des SOA Spezial Sonderhe... http://bit.ly/PAWwN9 Oracle SOA ?Flip thru new interactive "Oracle SOA Suite eBook-In the Customers Words" #middleware #soa #oraclesoa http://pub.vitrue.com/NzFZ SOA Community Follow SOA Community on Facebook http://www.facebook.com/soacommunity #soacommunity #opn SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Technorati Tags: SOA Community twitter,SOA Community,Oracle SOA,Oracle BPM,BPM Community,OPN,Jürgen Kress

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C#: Optional Parameters - Pros and Pitfalls

- by James Michael Hare

When Microsoft rolled out Visual Studio 2010 with C# 4, I was very excited to learn how I could apply all the new features and enhancements to help make me and my team more productive developers. Default parameters have been around forever in C++, and were intentionally omitted in Java in favor of using overloading to satisfy that need as it was though that having too many default parameters could introduce code safety issues. To some extent I can understand that move, as I’ve been bitten by default parameter pitfalls before, but at the same time I feel like Java threw out the baby with the bathwater in that move and I’m glad to see C# now has them. This post briefly discusses the pros and pitfalls of using default parameters. I’m avoiding saying cons, because I really don’t believe using default parameters is a negative thing, I just think there are things you must watch for and guard against to avoid abuses that can cause code safety issues. Pro: Default Parameters Can Simplify Code Let’s start out with positives. Consider how much cleaner it is to reduce all the overloads in methods or constructors that simply exist to give the semblance of optional parameters. For example, we could have a Message class defined which allows for all possible initializations of a Message: 1: public class Message 2: { 3: // can either cascade these like this or duplicate the defaults (which can introduce risk) 4: public Message() 5: : this(string.Empty) 6: { 7: } 8: 9: public Message(string text) 10: : this(text, null) 11: { 12: } 13: 14: public Message(string text, IDictionary<string, string> properties) 15: : this(text, properties, -1) 16: { 17: } 18: 19: public Message(string text, IDictionary<string, string> properties, long timeToLive) 20: { 21: // ... 22: } 23: } Now consider the same code with default parameters: 1: public class Message 2: { 3: // can either cascade these like this or duplicate the defaults (which can introduce risk) 4: public Message(string text = "", IDictionary<string, string> properties = null, long timeToLive = -1) 5: { 6: // ... 7: } 8: } Much more clean and concise and no repetitive coding! In addition, in the past if you wanted to be able to cleanly supply timeToLive and accept the default on text and properties above, you would need to either create another overload, or pass in the defaults explicitly. With named parameters, though, we can do this easily: 1: var msg = new Message(timeToLive: 100); Pro: Named Parameters can Improve Readability I must say one of my favorite things with the default parameters addition in C# is the named parameters. It lets code be a lot easier to understand visually with no comments. Think how many times you’ve run across a TimeSpan declaration with 4 arguments and wondered if they were passing in days/hours/minutes/seconds or hours/minutes/seconds/milliseconds. A novice running through your code may wonder what it is. Named arguments can help resolve the visual ambiguity: 1: // is this days/hours/minutes/seconds (no) or hours/minutes/seconds/milliseconds (yes) 2: var ts = new TimeSpan(1, 2, 3, 4); 3: 4: // this however is visually very explicit 5: var ts = new TimeSpan(days: 1, hours: 2, minutes: 3, seconds: 4); Or think of the times you’ve run across something passing a Boolean literal and wondered what it was: 1: // what is false here? 2: var sub = CreateSubscriber(hostname, port, false); 3: 4: // aha! Much more visibly clear 5: var sub = CreateSubscriber(hostname, port, isBuffered: false); Pitfall: Don't Insert new Default Parameters In Between Existing Defaults Now let’s consider a two potential pitfalls. The first is really an abuse. It’s not really a fault of the default parameters themselves, but a fault in the use of them. Let’s consider that Message constructor again with defaults. Let’s say you want to add a messagePriority to the message and you think this is more important than a timeToLive value, so you decide to put messagePriority before it in the default, this gives you: 1: public class Message 2: { 3: public Message(string text = "", IDictionary<string, string> properties = null, int priority = 5, long timeToLive = -1) 4: { 5: // ... 6: } 7: } Oh boy have we set ourselves up for failure! Why? Think of all the code out there that could already be using the library that already specified the timeToLive, such as this possible call: 1: var msg = new Message(“An error occurred”, myProperties, 1000); Before this specified a message with a TTL of 1000, now it specifies a message with a priority of 1000 and a time to live of -1 (infinite). All of this with NO compiler errors or warnings. So the rule to take away is if you are adding new default parameters to a method that’s currently in use, make sure you add them to the end of the list or create a brand new method or overload. Pitfall: Beware of Default Parameters in Inheritance and Interface Implementation Now, the second potential pitfalls has to do with inheritance and interface implementation. I’ll illustrate with a puzzle: 1: public interface ITag 2: { 3: void WriteTag(string tagName = "ITag"); 4: } 5: 6: public class BaseTag : ITag 7: { 8: public virtual void WriteTag(string tagName = "BaseTag") { Console.WriteLine(tagName); } 9: } 10: 11: public class SubTag : BaseTag 12: { 13: public override void WriteTag(string tagName = "SubTag") { Console.WriteLine(tagName); } 14: } 15: 16: public static class Program 17: { 18: public static void Main() 19: { 20: SubTag subTag = new SubTag(); 21: BaseTag subByBaseTag = subTag; 22: ITag subByInterfaceTag = subTag; 23: 24: // what happens here? 25: subTag.WriteTag(); 26: subByBaseTag.WriteTag(); 27: subByInterfaceTag.WriteTag(); 28: } 29: } What happens? Well, even though the object in each case is SubTag whose tag is “SubTag”, you will get: 1: SubTag 2: BaseTag 3: ITag Why? Because default parameter are resolved at compile time, not runtime! This means that the default does not belong to the object being called, but by the reference type it’s being called through. Since the SubTag instance is being called through an ITag reference, it will use the default specified in ITag. So the moral of the story here is to be very careful how you specify defaults in interfaces or inheritance hierarchies. I would suggest avoiding repeating them, and instead concentrating on the layer of classes or interfaces you must likely expect your caller to be calling from. For example, if you have a messaging factory that returns an IMessage which can be either an MsmqMessage or JmsMessage, it only makes since to put the defaults at the IMessage level since chances are your user will be using the interface only. So let’s sum up. In general, I really love default and named parameters in C# 4.0. I think they’re a great tool to help make your code easier to read and maintain when used correctly. On the plus side, default parameters: Reduce redundant overloading for the sake of providing optional calling structures. Improve readability by being able to name an ambiguous argument. But remember to make sure you: Do not insert new default parameters in the middle of an existing set of default parameters, this may cause unpredictable behavior that may not necessarily throw a syntax error – add to end of list or create new method. Be extremely careful how you use default parameters in inheritance hierarchies and interfaces – choose the most appropriate level to add the defaults based on expected usage. Technorati Tags: C#,.NET,Software,Default Parameters

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SQL Server Split() Function

- by HighAltitudeCoder

Title goes here Ever wanted a dbo.Split() function, but not had the time to debug it completely? Let me guess - you are probably working on a stored procedure with 50 or more parameters; two or three of them are parameters of differing types, while the other 47 or so all of the same type (id1, id2, id3, id4, id5...). Worse, you've found several other similar stored procedures with the ONLY DIFFERENCE being the number of like parameters taped to the end of the parameter list. If this is the situation you find yourself in now, you may be wondering, "why am I working with three different copies of what is basically the same stored procedure, and why am I having to maintain changes in three different places? Can't I have one stored procedure that accomplishes the job of all three? My answer to you: YES! Here is the Split() function I've created. /****************************************************************************** Split.sql ******************************************************************************/ /****************************************************************************** Split a delimited string into sub-components and return them as a table. Parameter 1: Input string which is to be split into parts. Parameter 2: Delimiter which determines the split points in input string. Works with space or spaces as delimiter. Split() is apostrophe-safe. SYNTAX: SELECT * FROM Split('Dvorak,Debussy,Chopin,Holst', ',') SELECT * FROM Split('Denver|Seattle|San Diego|New York', '|') SELECT * FROM Split('Denver is the super-awesomest city of them all.', ' ') ******************************************************************************/ USE AdventureWorks GO IF EXISTS (SELECT * FROM sysobjects WHERE xtype = 'TF' AND name = 'Split' ) BEGIN DROP FUNCTION Split END GO CREATE FUNCTION Split ( @InputString VARCHAR(8000), @Delimiter VARCHAR(50) ) RETURNS @Items TABLE ( Item VARCHAR(8000) ) AS BEGIN IF @Delimiter = ' ' BEGIN SET @Delimiter = ',' SET @InputString = REPLACE(@InputString, ' ', @Delimiter) END IF (@Delimiter IS NULL OR @Delimiter = '') SET @Delimiter = ',' --INSERT INTO @Items VALUES (@Delimiter) -- Diagnostic --INSERT INTO @Items VALUES (@InputString) -- Diagnostic DECLARE @Item VARCHAR(8000) DECLARE @ItemList VARCHAR(8000) DECLARE @DelimIndex INT SET @ItemList = @InputString SET @DelimIndex = CHARINDEX(@Delimiter, @ItemList, 0) WHILE (@DelimIndex != 0) BEGIN SET @Item = SUBSTRING(@ItemList, 0, @DelimIndex) INSERT INTO @Items VALUES (@Item) -- Set @ItemList = @ItemList minus one less item SET @ItemList = SUBSTRING(@ItemList, @DelimIndex+1, LEN(@ItemList)-@DelimIndex) SET @DelimIndex = CHARINDEX(@Delimiter, @ItemList, 0) END -- End WHILE IF @Item IS NOT NULL -- At least one delimiter was encountered in @InputString BEGIN SET @Item = @ItemList INSERT INTO @Items VALUES (@Item) END -- No delimiters were encountered in @InputString, so just return @InputString ELSE INSERT INTO @Items VALUES (@InputString) RETURN END -- End Function GO ---- Set Permissions --GRANT SELECT ON Split TO UserRole1 --GRANT SELECT ON Split TO UserRole2 --GO The syntax is basically as follows: SELECT <fields> FROM Table 1 JOIN Table 2 ON ... JOIN Table 3 ON ... WHERE LOGICAL CONDITION A AND LOGICAL CONDITION B AND LOGICAL CONDITION C AND TABLE2.Id IN (SELECT * FROM Split(@IdList, ',')) @IdList is a parameter passed into the stored procedure, and the comma (',') is the delimiter you have chosen to split the parameter list on. You can also use it like this: SELECT <fields> FROM Table 1 JOIN Table 2 ON ... JOIN Table 3 ON ... WHERE LOGICAL CONDITION A AND LOGICAL CONDITION B AND LOGICAL CONDITION C HAVING COUNT(SELECT * FROM Split(@IdList, ',') Similarly, it can be used in other aggregate functions at run-time: SELECT MIN(SELECT * FROM Split(@IdList, ','), <fields> FROM Table 1 JOIN Table 2 ON ... JOIN Table 3 ON ... WHERE LOGICAL CONDITION A AND LOGICAL CONDITION B AND LOGICAL CONDITION C GROUP BY <fields> Now that I've (hopefully effectively) explained the benefits to using this function and implementing it in one or more of your database objects, let me warn you of a caveat that you are likely to encounter. You may have a team member who waits until the right moment to ask you a pointed question: "Doesn't this function just do the same thing as using the IN function? Why didn't you just use that instead? In other words, why bother with this function?" What's happening is, one or more team members has failed to understand the reason for implementing this kind of function in the first place. (Note: this is THE MOST IMPORTANT ASPECT OF THIS POST). Allow me to outline a few pros to implementing this function, so you may effectively parry this question. Touche. 1) Code consolidation. You don't have to maintain what is basically the same code and logic, but with varying numbers of the same parameter in several SQL objects. I'm not going to go into the cons related to using this function, because the afore mentioned team member is probably more than adept at pointing these out. Remember, the real positive contribution is ou are decreasing the liklihood that your team fails to update all (x) duplicate copies of what are basically the same stored procedure, and so on... This is the classic downside to duplicate code. It is a virus, and you should kill it. You might be better off rejecting your team member's question, and responding with your own: "Would you rather maintain the same logic in multiple different stored procedures, and hope that the team doesn't forget to always update all of them at the same time?". In his head, he might be thinking "yes, I would like to maintain several different copies of the same stored procedure", although you probably will not get such a direct response. 2) Added flexibility - you can use the Split function elsewhere, and for splitting your data in different ways. Plus, you can use any kind of delimiter you wish. How can you know today the ways in which you might want to examine your data tomorrow? Segue to my next point. 3) Because the function takes a delimiter parameter, you can split the data in any number of ways. This greatly increases the utility of such a function and enables your team to work with the data in a variety of different ways in the future. You can split on a single char, symbol, word, or group of words. You can split on spaces. (The list goes on... test it out). Finally, you can dynamically define the behavior of a stored procedure (or other SQL object) at run time, through the use of this function. Rather than have several objects that accomplish almost the same thing, why not have only one instead?

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What's up with LDoms: Part 2 - Creating a first, simple guest

- by Stefan Hinker

Welcome back! In the first part, we discussed the basic concepts of LDoms and how to configure a simple control domain. We saw how resources were put aside for guest systems and what infrastructure we need for them. With that, we are now ready to create a first, very simple guest domain. In this first example, we'll keep things very simple. Later on, we'll have a detailed look at things like sizing, IO redundancy, other types of IO as well as security. For now,let's start with this very simple guest. It'll have one core's worth of CPU, one crypto unit, 8GB of RAM, a single boot disk and one network port. CPU and RAM are easy. The network port we'll create by attaching a virtual network port to the vswitch we created in the primary domain. This is very much like plugging a cable into a computer system on one end and a network switch on the other. For the boot disk, we'll need two things: A physical piece of storage to hold the data - this is called the backend device in LDoms speak. And then a mapping between that storage and the guest domain, giving it access to that virtual disk. For this example, we'll use a ZFS volume for the backend. We'll discuss what other options there are for this and how to chose the right one in a later article. Here we go: root@sun # ldm create mars root@sun # ldm set-vcpu 8 mars root@sun # ldm set-mau 1 mars root@sun # ldm set-memory 8g mars root@sun # zfs create rpool/guests root@sun # zfs create -V 32g rpool/guests/mars.bootdisk root@sun # ldm add-vdsdev /dev/zvol/dsk/rpool/guests/mars.bootdisk \ mars.root@primary-vds root@sun # ldm add-vdisk root mars.root@primary-vds mars root@sun # ldm add-vnet net0 switch-primary mars That's all, mars is now ready to power on. There are just three commands between us and the OK prompt of mars: We have to "bind" the domain, start it and connect to its console. Binding is the process where the hypervisor actually puts all the pieces that we've configured together. If we made a mistake, binding is where we'll be told (starting in version 2.1, a lot of sanity checking has been put into the config commands themselves, but binding will catch everything else). Once bound, we can start (and of course later stop) the domain, which will trigger the boot process of OBP. By default, the domain will then try to boot right away. If we don't want that, we can set "auto-boot?" to false. Finally, we'll use telnet to connect to the console of our newly created guest. The output of "ldm list" shows us what port has been assigned to mars. By default, the console service only listens on the loopback interface, so using telnet is not a large security concern here. root@sun # ldm set-variable auto-boot\?=false mars root@sun # ldm bind mars root@sun # ldm start mars root@sun # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-cv- UART 8 7680M 0.5% 1d 4h 30m mars active -t---- 5000 8 8G 12% 1s root@sun # telnet localhost 5000 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. ~Connecting to console "mars" in group "mars" .... Press ~? for control options .. {0} ok banner SPARC T3-4, No Keyboard Copyright (c) 1998, 2011, Oracle and/or its affiliates. All rights reserved. OpenBoot 4.33.1, 8192 MB memory available, Serial # 87203131. Ethernet address 0:21:28:24:1b:50, Host ID: 85241b50. {0} ok We're done, mars is ready to install Solaris, preferably using AI, of course ;-) But before we do that, let's have a little look at the OBP environment to see how our virtual devices show up here: {0} ok printenv auto-boot? auto-boot? = false {0} ok printenv boot-device boot-device = disk net {0} ok devalias root /virtual-devices@100/channel-devices@200/disk@0 net0 /virtual-devices@100/channel-devices@200/network@0 net /virtual-devices@100/channel-devices@200/network@0 disk /virtual-devices@100/channel-devices@200/disk@0 virtual-console /virtual-devices/console@1 name aliases We can see that setting the OBP variable "auto-boot?" to false with the ldm command worked. Of course, we'd normally set this to "true" to allow Solaris to boot right away once the LDom guest is started. The setting for "boot-device" is the default "disk net", which means OBP would try to boot off the devices pointed to by the aliases "disk" and "net" in that order, which usually means "disk" once Solaris is installed on the disk image. The actual devices these aliases point to are shown with the command "devalias". Here, we have one line for both "disk" and "net". The device paths speak for themselves. Note that each of these devices has a second alias: "net0" for the network device and "root" for the disk device. These are the very same names we've given these devices in the control domain with the commands "ldm add-vnet" and "ldm add-vdisk". Remember this, as it is very useful once you have several dozen disk devices... To wrap this up, in this part we've created a simple guest domain, complete with CPU, memory, boot disk and network connectivity. This should be enough to get you going. I will cover all the more advanced features and a little more theoretical background in several follow-on articles. For some background reading, I'd recommend the following links: LDoms 2.2 Admin Guide: Setting up Guest Domains Virtual Console Server: vntsd manpage - This includes the control sequences and commands available to control the console session. OpenBoot 4.x command reference - All the things you can do at the ok prompt

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Is the Cloud ready for an Enterprise Java web application? Seeking a JEE hosting advice.

- by Jakub Holý

Greetings to all the smart people around here! I'd like to ask whether it is feasible or a good idea at all to deploy a Java enterprise web application to a Cloud such as Amazon EC2. More exactly, I'm looking for infrastructure options for an application that shall handle few hundred users with long but neither CPU nor memory intensive sessions. I'm considering dedicated servers, virtual private servers (VPSs) and EC2. I've noticed that there is a project called JBoss Cloud so people are working on enabling such a deployment, on the other hand it doesn't seem to be mature yet and I'm not sure that the cloud is ready for this kind of applications, which differs from the typical cloud-based applications like Twitter. Would you recommend to deploy it to the cloud? What are the pros and cons? The application is a Java EE 5 web application whose main function is to enable users to compose their own customized Product by combining the available Parts. It uses stateless and stateful session beans and JPA for persistence of entities to a RDBMS and fetches information about Parts from the company's inventory system via a web service. Aside of external users it's used also by few internal ones, who are authenticated against the company's LDAP. The application should handle around 300-400 concurrent users building their product and should be reasonably scalable and available though these qualities are only of a medium importance at this stage. I've proposed an architecture consisting of a firewall (FW) and load balancer supporting sticky sessions and https (in the Cloud this would be replaced with EC2's Elastic Load Balancing service and FW on the app. servers, in a physical architecture the load-balancer would be a HW), then two physical clustered application servers combined with web servers (so that if one fails, a user doesn't loose his/her long built product) and finally a database server. The DB server would need a slave backup instance that can replace the master instance if it fails. This should provide reasonable availability and fault tolerance and provide good scalability as long as a single RDBMS can keep with the load, which should be OK for quite a while because most of the operations are done in the memory using a stateful bean and only occasionally stored or retrieved from the DB and the amount of data is low too. A problematic part could be the dependency on the remote inventory system webservice but with good caching of its outputs in the application it should be OK too. Unfortunately I've only vague idea of the system resources (memory size, number and speed of CPUs/cores) that such an "average Java EE application" for few hundred users needs. My rough and mostly unfounded estimate based on actual Amazon offerings is that 1.7GB and a single, 2-core "modern CPU" with speed around 2.5GHz (the High-CPU Medium Instance) should be sufficient for any of the two application servers (since we can handle higher load by provisioning more of them). Alternatively I would consider using the Large instance (64b, 7.5GB RAM, 2 cores at 1GHz) So my question is whether such a deployment to the cloud is technically and financially feasible or whether dedicated/VPS servers would be a better option and whether there are some real-world experiences with something similar. Thank you very much! /Jakub Holy PS: I've found the JBoss EAP in a Cloud Case Study that shows that it is possible to deploy a real-world Java EE application to the EC2 cloud but unfortunately there're no details regarding topology, instance types, or anything :-(

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Running Solaris 11 as a control domain on a T2000

- by jsavit

There is increased adoption of Oracle Solaris 11, and many customers are deploying it on systems that previously ran Solaris 10. That includes older T1-processor based systems like T1000 and T2000. Even though they are old (from 2005) and don't have the performance of current SPARC servers, they are still functional, stable servers that customers continue to operate. One reason to install Solaris 11 on them is that older machines are attractive for testing OS upgrades before updating current, production systems. Normally this does not present a challenge, because Solaris 11 runs on any T-series or M-series SPARC server. One scenario adds a complication: running Solaris 11 in a control domain on a T1000 or T2000 hosting logical domains. Solaris 11 pre-installed Oracle VM Server for SPARC incompatible with T1 Unlike Solaris 10, Solaris 11 comes with Oracle VM Server for SPARC preinstalled. The ldomsmanager package contains the logical domains manager for Oracle VM Server for SPARC 2.2, which requires a SPARC T2, T2+, T3, or T4 server. It does not work with T1-processor systems, which are only supported by LDoms Manager 1.2 and earlier. The following screenshot shows what happens (bold font) if you try to use Oracle VM Server for SPARC 2.x commands in a Solaris 11 control domain. The commands were issued in a control domain on a T2000 that previously ran Solaris 10. We also display the version of the logical domains manager installed in Solaris 11: root@t2000 psrinfo -vp The physical processor has 4 virtual processors (0-3) UltraSPARC-T1 (chipid 0, clock 1200 MHz) # prtconf|grep T SUNW,Sun-Fire-T200 # ldm -V Failed to connect to logical domain manager: Connection refused # pkg info ldomsmanager Name: system/ldoms/ldomsmanager Summary: Logical Domains Manager Description: LDoms Manager - Virtualization for SPARC T-Series Category: System/Virtualization State: Installed Publisher: solaris Version: 2.2.0.0 Build Release: 5.11 Branch: 0.175.0.8.0.3.0 Packaging Date: May 25, 2012 10:20:48 PM Size: 2.86 MB FMRI: pkg://solaris/system/ldoms/[email protected],5.11-0.175.0.8.0.3.0:20120525T222048Z The 2.2 version of the logical domains manager will have to be removed, and 1.2 installed, in order to use this as a control domain. Preparing to change - create a new boot environment Before doing anything else, lets create a new boot environment: # beadm list BE Active Mountpoint Space Policy Created -- ------ ---------- ----- ------ ------- solaris NR / 2.14G static 2012-09-25 10:32 # beadm create solaris-1 # beadm activate solaris-1 # beadm list BE Active Mountpoint Space Policy Created -- ------ ---------- ----- ------ ------- solaris N / 4.82M static 2012-09-25 10:32 solaris-1 R - 2.14G static 2012-09-29 11:40 # init 0 Normally an init 6 to reboot would have been sufficient, but in the next step I reset the system anyway in order to put the system in factory default mode for a "clean" domain configuration. Preparing to change - reset to factory default There was a leftover domain configuration on the T2000, so I reset it to the factory install state. Since the ldm command is't working yet, it can't be done from the control domain, so I did it by logging onto to the service processor: $ ssh -X admin@t2000-sc Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved. Oracle Advanced Lights Out Manager CMT v1.7.9 Please login: admin Please Enter password: ******** sc> showhost Sun-Fire-T2000 System Firmware 6.7.10 2010/07/14 16:35 Host flash versions: OBP 4.30.4.b 2010/07/09 13:48 Hypervisor 1.7.3.c 2010/07/09 15:14 POST 4.30.4.b 2010/07/09 14:24 sc> bootmode config="factory-default" sc> poweroff Are you sure you want to power off the system [y/n]? y SC Alert: SC Request to Power Off Host. SC Alert: Host system has shut down. sc> poweron SC Alert: Host System has Reset At this point I rebooted into the new Solaris 11 boot environment, and Solaris commands showed it was running on the factory default configuration of a single domain owning all 32 CPUs and 32GB of RAM (that's what it looked like in 2005.) # psrinfo -vp The physical processor has 8 cores and 32 virtual processors (0-31) The core has 4 virtual processors (0-3) The core has 4 virtual processors (4-7) The core has 4 virtual processors (8-11) The core has 4 virtual processors (12-15) The core has 4 virtual processors (16-19) The core has 4 virtual processors (20-23) The core has 4 virtual processors (24-27) The core has 4 virtual processors (28-31) UltraSPARC-T1 (chipid 0, clock 1200 MHz) # prtconf|grep Mem Memory size: 32640 Megabytes Note that the older processor has 4 virtual CPUs per core, while current processors have 8 per core. Remove ldomsmanager 2.2 and install the 1.2 version The Solaris 11 pkg command is now used to remove the 2.2 version that shipped with Solaris 11: # pkg uninstall ldomsmanager Packages to remove: 1 Create boot environment: No Create backup boot environment: No Services to change: 2 PHASE ACTIONS Removal Phase 130/130 PHASE ITEMS Package State Update Phase 1/1 Package Cache Update Phase 1/1 Image State Update Phase 2/2 Finally, LDoms 1.2 installed via its install script, the same way it was done years ago: # unzip LDoms-1_2-Integration-10.zip # cd LDoms-1_2-Integration-10/Install/ # ./install-ldm Welcome to the LDoms installer. You are about to install the Logical Domains Manager package that will enable you to create, destroy and control other domains on your system. Given the capabilities of the LDoms domain manager, you can now change the security configuration of this Solaris instance using the Solaris Security Toolkit. ... ... normal install messages omitted ... The Solaris Security Toolkit applies to Solaris 10, and cannot be used in Solaris 11 (in which several things hardened by the Toolkit are already hardened by default), so answer b in the choice below: You are about to install the Logical Domains Manager package that will enable you to create, destroy and control other domains on your system. Given the capabilities of the LDoms domain manager, you can now change the security configuration of this Solaris instance using the Solaris Security Toolkit. Select a security profile from this list: a) Hardened Solaris configuration for LDoms (recommended) b) Standard Solaris configuration c) Your custom-defined Solaris security configuration profile Enter a, b, or c [a]: b ... other install messages omitted for brevity... After install I ensure that the necessary services are enabled, and verify the version of the installed LDoms Manager: # svcs ldmd STATE STIME FMRI online 22:00:36 svc:/ldoms/ldmd:default # svcs vntsd STATE STIME FMRI disabled Aug_19 svc:/ldoms/vntsd:default # ldm -V Logical Domain Manager (v 1.2-debug) Hypervisor control protocol v 1.3 Using Hypervisor MD v 1.1 System PROM: Hypervisor v. 1.7.3. @(#)Hypervisor 1.7.3.c 2010/07/09 15:14\015 OpenBoot v. 4.30.4. @(#)OBP 4.30.4.b 2010/07/09 13:48 Set up control domain and domain services At this point we have a functioning LDoms 1.2 environment that can be configured in the usual fashion. One difference is that LDoms 1.2 behavior had 'delayed configuration mode (as expected) during initial configuration before rebooting the control domain. Another minor difference with a Solaris 11 control domain is that you define virtual switches using the 'vanity name' of the network interface, rather than the hardware driver name as in Solaris 10. # ldm list ------------------------------------------------------------------------------ Notice: the LDom Manager is running in configuration mode. Configuration and resource information is displayed for the configuration under construction; not the current active configuration. The configuration being constructed will only take effect after it is downloaded to the system controller and the host is reset. ------------------------------------------------------------------------------ NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-c-- SP 32 32640M 3.2% 4d 2h 50m # ldm add-vdiskserver primary-vds0 primary # ldm add-vconscon port-range=5000-5100 primary-vcc0 primary # ldm add-vswitch net-dev=net0 primary-vsw0 primary # ldm set-mau 2 primary # ldm set-vcpu 8 primary # ldm set-memory 4g primary # ldm add-config initial # ldm list-spconfig factory-default initial [current] That's it, really. After reboot, we are ready to install guest domains. Summary - new wine in old bottles This example shows that (new) Solaris 11 can be installed on (old) T2000 servers and used as a control domain. The main activity is to remove the preinstalled Oracle VM Server for 2.2 and install Logical Domains 1.2 - the last version of LDoms to support T1-processor systems. I tested Solaris 10 and Solaris 11 guest domains running on this server and they worked without any surprises. This is a viable way to get further into Solaris 11 adoption, even on older T-series equipment.

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