Search Results

Search found 13723 results on 549 pages for 'constraint programming'.

Page 311/549 | < Previous Page | 307 308 309 310 311 312 313 314 315 316 317 318  | Next Page >

• some examples for using specific searchalgorithm

  - by Robert

  I could understand the following search algorithms: Constraint Satisfaction with Arc Consistency, Uninformed search A* Search MinMax I would understand the definition and working principles of the above algorithm,but could you please give me some real world examples that the above algorithms will be suitable?My idea would be: For CSP with Arc Consistency,assign students to groups that each group must contain both technical and management students,and no 2 technical students in a same group. Uniformed Search: search for a file under UNIX directoy. A* Search: search a way (staring from home) to go to mulitple stores to buy things then get back home with minimum total travelling time. MinMax:Go or other Chess. Please correct me if I am wrong.

  Read the article

• efficiently trimming postgresql tables

  - by agilefall

  I have about 10 tables with over 2 million records and one with 30 million. I would like to efficiently remove older data from each of these tables. My general algorithm is: create a temp table for each large table and populate it with newer data truncate the original tables copy tmp data back to original tables using: "insert into originaltable (select * from tmp_table)" However, the last step of copying the data back is taking longer than I'd like. I thought about deleting the original tables and making the temp tables "permanent", but I lose constraint/foreign key info. If I delete from the tables directly, it takes much longer. Given that I need to preserve all foreign keys and constraints, are there any faster ways of removing the older data? Thanks.

  Read the article

• Interpreting type codes in sys.objects in SQL Server

  - by fatcat1111

  On SQL Server, the sys.objects table includes "Type" and "Type_Desc" attributes. For example: SELECT DISTINCT [Type], Type_Desc FROM Sys.Objects ORDER BY [Type] Returns: C CHECK_CONSTRAINT D DEFAULT_CONSTRAINT F FOREIGN_KEY_CONSTRAINT FN SQL_SCALAR_FUNCTION FS CLR_SCALAR_FUNCTION IT INTERNAL_TABLE P SQL_STORED_PROCEDURE PK PRIMARY_KEY_CONSTRAINT S SYSTEM_TABLE SQ SERVICE_QUEUE TR SQL_TRIGGER U USER_TABLE UQ UNIQUE_CONSTRAINT V VIEW Is there a comprehensive list of these types somewhere? There isn't a constraint on sys.objects that points me to table of these, and sys.types contains data types. I've searched SQL BOL but haven't found it. Any help would be appreciated. EDIT: Some DBs use only a subset of these types. For example, if I have a database with no views, when I query Sys.Objects as above, there are no "V" rows in the results. I am looking for a list of all possible types and descriptions used by SQL Server.

  Read the article

• Why is 'virtual' optional for overridden methods in derived classes?

  - by squelart

  When a method is declared as virtual in a class, its overrides in derived classes are automatically considered virtual as well, and the C++ language makes this keyword virtual optional in this case: class Base { virtual void f(); }; class Derived : public Base { void f(); // 'virtual' is optional but implied. }; My question is: What is the rationale for making virtual optional? I know that it is not absolutely necessary for the compiler to be told that, but I would think that developers would benefit if such a constraint was enforced by the compiler. E.g., sometimes when I read others' code I wonder if a method is virtual and I have to track down its superclasses to determine that. And some coding standards (Google) make it a 'must' to put the virtual keyword in all subclasses.

  Read the article

• What is the best way to reject messages with the same body in AMQ queue?

  - by archer

  I have a single AMQ queue that receives simple messages with string body. Consider I'm sending CLSIDs as message bodies. CLSIDs could be not unique, but I'd like to reject all messages with not unique bodies and keep only single instance of such messages in the queue. Is there any simple way to do it? Currently I'm using a workaround. Messages from the queue are consumed by some processor that tries to insert bodies into a simple DB table with UNIQUE constraint applied to message_body field. If processor inserts the messages succesfuly - it's assigned to exchange.out.body and sent to other queue. If ConstraintViolationException is thrown - nothing is resent to other queue. I would like to know does AMQ support something similar out of the box?

  Read the article

• What are the repercussions of not checking existing data when adding a foreign key?

  - by scottm

  I've inherited a database that doesn't exactly strive for data integrity. I am trying to add some foreign keys to change that, but there is data in some tables that doesn't fit the constraints. Most likely, the data won't be used again so I want to know what problems I might face by leaving it there. The other option I see is to move it into some kind of table without referential constraints, just for historical purposes. So, what are the repercussions of not checking existing data? If I create a foreign key constraint on a table and don't check existing data, will all new data inserted into the table be enforced?

  Read the article

• Symfony 1.4: Deleting a sfGuardUser

  - by Tom

  Hi, I'm having some trouble with the following... I have a sfGuardUser table set up normally, and it has a one-to-one relationship with a Profile table, which contains some additional user info. When a user wants to delete themselves from the site, I'd like to retain their info in the Profile table for various purposes BUT delete the sfGuardUser in order to keep that table cleaner/shorter (not just set it to inactive). I was under the impression that I could set the FK in the Profile table to NULL and then delete the sfGuardUser, but it seems the FK-constraint fails. Indeed, it seems I can't delete either and the queries fail: If I try to delete the sfGuardUser, the Profile table will have an invalid FK If I try to delete a Profile, the sfGuardUser will have an invalid FK Other than leaving outdated sfGuardUsers and Profiles in these tables, or having to use a cascaded delete to get rid of both, can anyone tell me if there's any other way around this? Thank you.

  Read the article

• Haskell: Defaulting constraints to type

  - by yairchu

  Consider this example: applyKTimes :: Integral i => i -> (a -> a) -> a -> a applyKTimes 0 _ x = x applyKTimes k f x = applyKTimes (k-1) f (f x) applyThrice :: (a -> a) -> a -> a applyThrice = applyKTimes 3 The 3 in applyThrice is defaulted by GHC to an Integer as shown when compiling with -Wall: Warning: Defaulting the following constraint(s) to type 'Integer' 'Integral t' arising from a use of 'applyKTimes' So I guess that Integer is the default Integral a => a. Is there a way to define "default types" for other constraints too? Is using default types bad practice? (it does complain when using -Wall..)

  Read the article

• MVC Framework for existing application.

  - by Dhruva

  I am modifying existing java web application that was written long time ago, and it is written in the wrost possible way. It has business logic and sql statemens in JSP files. Because of the certain constraint, I can not re-design the entire application. but I can implement better design in any new feature that I add. can anybody suggest me any MVC framework that I could easily integrate in existing app. I need to have framework that is not depended on many external jar files and it does not cause any issues with existing application.

  Read the article

• SQL Server 2000, how to automate import data from excel

  - by Stan

  Say the source data comes in excel format, below is how I import the data. Converting to csv format via MS Excel Roughly find bad rows/columns by inspecting backup the table that needs to be updated in SQL Query Analyzer truncate the table (may need to drop foreign key constraint as well) import data from the revised csv file in SQL Server Enterprise Manager If there's an error like duplicate columns, I need to check the original csv and remove them I was wondering how to make this procedure more effecient in every step? I have some idea but not complete. For step 2&6, using scripts that can check automatically and print out all error row/column data. So it's easier to remove all errors once. For step 3&5, is there any way to automatically update the table without manually go through the importing steps? Could the community advise, please? Thanks.

  Read the article

• Add Unique Key For Nullable Columns - SQL Server

  - by Ruby

  I'm using sql server 2008 R2 and would like to apply unique key constraint to nullable columns. This code works good, but if I have multiple columns to add this rule to, it would generate as many 'nullbuster' columns. ALTER TABLE tblBranch ADD nullbuster AS (CASE WHEN column1 IS NULL THEN BranchID ELSE NULL END); CREATE UNIQUE INDEX UK_Column1 ON tblBranch(column1,nullbuster); tblBranch is the table name, nullbuster would be the new column name, BranchId is the Primary key column of the target table, and Column1 is the column name of the target column. Is there any way that I could achieve the goal without generating new columns.

  Read the article

• Grails - Need to restrict fetched rows based on condition on join table

  - by sector7

  Hi guys, I have these two domains Car and Driver which have many-to-many relationship. This association is defined in table tblCarsDrivers which has, not surprisingly, primary keys of both the tables BUT additionally also has a new boolean field deleted. Herein lies the problem. When I find/get query on domain Car, I am fetched all related drivers irrespective of their deleted status in tblCarsDrivers, which is expected. I need to put a clause/constraint to exclude the deleted drivers from the list of fetched records. PS: I tried using an association domain CarDriver in joinTable name but that seems not to work. Apparently it expects only table names, not maps. PPS: I know its unnatural to have any other fields besides the mapping keys in mapping table but this is how I got it and it cant be changed. Car domain is defined as such - class Car { Integer id String name static hasMany = [drivers:Driver] static mapping = { table 'tblCars' version false drivers joinTable:[name: 'tblCarsDrivers',column:'driverid',key:'carid'] } } Thanks!

  Read the article

• Doubt in clustered and non Clustered index

  - by Mahesh

  I have a doubt that if my table do n't have any constraint like Primary Key,Foreign key,Unique key etc. then can i create the clustered index on table and clustered index can have the douplicate records ? My 2nd question is where should we exectly use the non clustered index and when it is useful and benificial to create in table? My 3rd question is How can we create the 249 non clustered index in a table .Is it the meaning, Creating the non clustered index on 249 columns ? Can you anyone help me to remove my confusion in this.

  Read the article

• Typeclass instances for unnamed types in Scala

  - by ncreep

  How would one encode the following constraint in Scala (pseudocode)? def foo(x: T forSome { type T has a Numeric[T] instance in scope }) = { val n= implicitly[...] // obtain the Numeric instance for x n.negate(x) // and use it with x } In words: I need a type class instance for my input argument, but I don't care about the argument's type, I just need to obtain the instance and use it on my argument. It doesn't have to be an existential type, but I need to avoid type parameters in the def's signature. Thanks.

  Read the article

• ORACLE -1401 error

  - by Sachin Chourasiya

  I have a stored procedure in Oracle 9i which inserts records in a table. The table has a primary key built to ensure duplicte rows doesnot exists. I am trying to insert a record by calling this stored procedure and it works first time properly. I am again trying to insert a duplicate record and expecting unique constraint violation error. But I am getting ORA-01401 inserted value too large for column I knew its meaning but my query is , if the value inserted is really large then how it got successful in the first attempt.

  Read the article

• Case insensitive expectations in Rhino Mocks

  - by user313886

  I'm using Rhino Mocks to expect a call. There is a single parameter which is a string. But I'm not bothered about the case of the string. I want the test to pass even if the case is wrong. So I'm doing the following: //expect log message to be called with a string parameter. //We want to ignore case when verifiyig so we use a constraint instead of a direct parameter Expect.Call(delegate { logger.LogMessage(null); }).Constraints(Is.Matching<string>(x => x.ToLower()=="f2")); It seems a bit log winded. Is there a more sensible way of doing this?

  Read the article

• SQL Server Composite Primary Keys

  - by Colin

  I am attempting to replace all records for a give day in a certain table. The table has a composite primary key comprised of 7 fields. One such field is date. I have deleted all records which have a date value of 2/8/2010. When I try to then insert records into the table for 2/8/2010, I get a primary key violation. The records I am attempting to insert are only for 2/8/2010. Since date is a component of the PK, shouldn't there be no way to violate the constraint as long as the date I'm inserting is not already in the table? Thanks in advance.

  Read the article

• How to solve 'Badly constructed integrity constraints' in doctrine

  - by Carson

  When I execute the command './doctrine build-all-reload' It comes out the following output: build-all-reload - Are you sure you wish to drop your databases? (y/n) y build-all-reload - Successfully dropped database for connection named 'doctrine' build-all-reload - Generated models successfully from YAML schema build-all-reload - Successfully created database for connection named 'doctrine' Badly constructed integrity constraints. Cannot define constraint of different f ields in the same table. Here is the source code of Doctrine that outputs the error: here What causes the error? How can I debug where the error comes from?

  Read the article

• Use of bit-torrent for large file download as an alternative to FTP

  - by questzen

  The company I work for procures large volumes of data and does this by subscribing to FTP locations. I was wondering if it is possible to download the same using a tracker, the major challenge is authentication of the users IMO. Most ftp servers we subscribe to have a restriction of the number of ftp connection attempts. Does any one here have any experience with this? Any advice is welcome. Edit To clarify, we subscribe to third party vendors and access their ftp location using credentials provided by them. The service is not exclusive to us, they do sell their data to several others. If we could be part of the swarm, the download rates would be pretty high without added penalty. The question is about the possibility of achieving this, so that we can put-forth a proposal in those lines. The vendors obviously wouldn't share data to non-subscribers, so that is a constraint.

  Read the article

• OpenERP model tracking external resource, hooking into parent's copy() or copy_data()

  - by CB.

  I have added a new model (call it crm_lead_external) that is linked via a new one2many on crm_lead. Thus, my module has two models defined: an updated crm_lead (with _name=crm_lead) and a new crm_lead_external. This external model tracks a file and as such has a 'filename' field. I also created a unique SQL index on this filename field. This is part of my module: def copy(self, cr, uid, id, default=None, context=None): if not default: default = {} default.update({ 'state': 'new', 'filename': '', }) ret = super(crm_lead_external, self).copy(cr, uid, id, default, context=context) #do file copy return ret The intent here is to allow an external entity to be duplicated, but to retarget the file path. Now, if I click duplicate on the Lead, I get an IntegrityError on my unique constraint. Is there a particular reason why copy() isn't being called? Should I add this logic to copy_data()? Myst I really override copy() for the lead? Thanks in advance.

  Read the article

• Truncating a table referenced by a foreign key

  - by born to hula

  Hey, We have two tables in a SQL Server 2005 database, A and B.There is a service which truncates table A every day. Recently, a foreign key constraint was added to table B, referencing table A. As a result, it isn't possible truncating table A anymore, even if table B is empty. Is there any workaround to get the same result as truncating table A? I've already tried the approach below but the identity wasn't reset. DBCC CHECKIDENT (TABLENAME, RESEED, 0) PS. before anyone points this as a duplicate, the different thing here is that I'm not allowed to drop constraints, nor creating any.

  Read the article

• Behaviour to simulate an enum implementing an interface

  - by fearofawhackplanet

  Say I have an enum something like: enum OrderStatus { AwaitingAuthorization, InProduction, AwaitingDespatch } I've also created an extension method on my enum to tidy up the displayed values in the UI, so I have something like: public static string ToDisplayString(this OrderStatus status) { switch (status) { case Status.AwaitingAuthorization: return "Awaiting Authorization"; case Status.InProduction: return "Item in Production"; ... etc } } Inspired by the excellent post here, I want to bind my enums to a SelectList with an extension method: public static SelectList ToSelectList<TEnum>(this TEnum enumObj) however, to use the DisplayString values in the UI drop down I'd need to add a constraint along the lines of : where TEnum has extension ToDisplayString Obviously none of this is going to work at all with the current approach, unless there's some clever trick I don't know about. Does anyone have any ideas about how I might be able to implement something like this?

  Read the article

• Oracle: TABLE ACCESS FULL with Primary key?

  - by tim

  There is a table: CREATE TABLE temp ( IDR decimal(9) NOT NULL, IDS decimal(9) NOT NULL, DT date NOT NULL, VAL decimal(10) NOT NULL, AFFID decimal(9), CONSTRAINT PKtemp PRIMARY KEY (IDR,IDS,DT) ) ; SQL>explain plan for select * from temp; Explained. SQL> select plan_table_output from table(dbms_xplan.display('plan_table',null,'serial')); PLAN_TABLE_OUTPUT -------------------------------------------------------------------------------- --------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| --------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | 61 | 2 (0)| | 1 | TABLE ACCESS FULL| TEMP | 1 | 61 | 2 (0)| --------------------------------------------------------------- Note ----- - 'PLAN_TABLE' is old version 11 rows selected. SQL server 2008 shows in the same situation Clustered index scan. What is the reason?

  Read the article

• deleting a large number of rows from a table

  - by Azeem

  We have a requirement to delete rows in the order of millions from multiple tables as a batch job (note that we are not deleting all the rows, we are deleting based on a timestamp stored in an indexed column). Obviously a normal DELETE takes forever (because of logging, referential constraint checking etc.). I know in the LUW world, we have ALTER TABLE NOT LOGGED INITIALLY but I can't seem to find the an equivalent SQL statement for DB2 v8 z/OS. Any one has any ideas on how to do this really fast? Also, any ideas on how to avoid the referential checks when deleting the rows? Please let me know.

  Read the article

• CodeIgniter Production and Developpement server on the same domain. (no subdomain)

  - by Onigoetz

  Hi, I googled this many times but now I have to ask it here. I want to make a workflow for a website for Developpement/Production. My constraint is that I use Facebook Connect (Facebook Graph now) so I need to have the dev and prod on the same domain and server. (to be able to log in and test the features) I thought I will edit the CodeIgniter Index.php to redirect if I have a specific user agent (I can edit the one of my firefox) You think it's a good Idea or you have a better one ? And now comes the eternal question : how can I deploy this the easy way ? should I use Capistrano or Phing ? or simply a script with SVN ? Please help me, I'm totally new to this Deployment thing. I used to work directly in production for my little websites or on other domains. but now it's not possible anymore.

  Read the article

< Previous Page | 307 308 309 310 311 312 313 314 315 316 317 318  | Next Page >