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  • Best way to close nested streams in Java?

    - by dirtyvagabond
    What is considered the best, most comprehensive way to close nested streams in Java? For example, consider the setup: FileOutputStream fos = new FileOutputStream(...) BufferedOS bos = new BufferedOS(fos); ObjectOutputStream oos = new ObjectOutputStream(bos); I understand the close operation needs to be insured (probably by using a finally clause). What I wonder about is, is it necessary to explicitly make sure the nested streams are closed, or is it enough to just make sure to close the outer stream (oos)? One thing I notice, at least dealing with this specific example, is that the inner streams only seem to throw FileNotFoundExceptions. Which would seem to imply that there's not technically a need to worry about closing them if they fail. Here's what a colleague wrote: Technically, if it were implemented right, closing the outermost stream (oos) should be enough. But the implementation seems flawed. Example: BufferedOutputStream inherits close() from FilterOutputStream, which defines it as: 155 public void close() throws IOException { 156 try { 157 flush(); 158 } catch (IOException ignored) { 159 } 160 out.close(); 161 } However, if flush() throws a runtime exception for some reason, then out.close() will never be called. So it seems "safest" (but ugly) to mostly worry about closing FOS, which is keeping the file open. What is considered to be the hands-down best, when-you-absolutely-need-to-be-sure, approach to closing nested streams? And are there any official Java/Sun docs that deal with this in fine detail?

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  • Repackaging Jasper-Reports into an application specific OSGi bundle, legal or not?

    - by Chris
    Hi, I wanted to ask (probably a silly) question regarding the packaging of existing open-source components as OSGi bundles (more specifically Jasper Reports). I have an application that I am converting from a monolithic jar-hell type architecture to something more moduler and OSGi is my weapon of choice. There are various modules I have in mind but one of the modules is a reporting module. My own reporting module will be a jar file containing my code that should reference a Jasper Reports bundle. Trouble is, Jasper reports depends on far far too many libraries and is quite monolithic in its own right. I therefore wish to build my own Jasper Reports bundle but this is where I start getting confused about the legality of repackaging. I don't plan to re-compile but I do plan to re-bundle removing known items that I do not require. Can anyone offer advice on whether I am permitted to repackage (not recompile or extend) open-source libraries into OSGi bundles without falling foul of 'derivative works' clause of LGPL? I noticed that Groovy seems to offer some monolithic jars that include all dependancies and actually goes so far as to re-arrange the packages of its dependancies so that there are no namespace conflicts. This seems to me to be a violation of the license but if anyone can reassure me that this is legal then I would feel safer about my less intrusive custom-bundling of Jasper reports. Thanks for your time, Chris

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  • 'Invalid column name [ColumnName]' on a nested linq query.

    - by Joe
    I've got the following query: ATable .GroupBy(x=> new {FieldA = x.FieldAID, FieldB = x.FieldBID, FieldC = x.FieldCID}) .Select(x=>new {FieldA = x.Key.FieldA, ..., last_seen = x.OrderByDescending(y=>y.Timestamp).FirstOrDefault().Timestamp}) results in: SqlException: Invalid column name 'FieldAID' x 5 SqlException: Invalid column name 'FieldBID' x 5 SqlException: Invalid column name 'FieldCID' x 1 I've worked out it has to do with the last query to Timestamp because this works: ATable .GroupBy(x=> new {FieldA = x.FieldAID, FieldB = x.FieldBID, FieldC = x.FieldCID}) .Select(x=>new {FieldA = x.Key.FieldA, ..., last_seen = x.OrderByDescending(y=>y.Timestamp).FirstOrDefault()}) The query has been simplified. The purpose is to group by a set of variables and then show the last time this grouping occured in the db. I'm using Linqpad 4 to generate these results so the Timestamp gives me a string whereas FirstOrDefault gives me the whole object which isn't ideal. Update On further testing I've noticed that the number and type of SQLException is related to the class created in the groupby clause. So, ATable .GroupBy(x=> new {FieldA = x.FieldAID}) .Select(x=>new {FieldA = x.Key.FieldA, last_seen = x.OrderByDescending(y=>y.Timestamp).FirstOrDefault()}) results in SqlException: Invalid column name 'FieldAID' x 5

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  • Makefile for DOS/Windows and Cygwin

    - by Thomas Matthews
    I need to have a makefile work under DOS (Windows) and Cygwin. I having problems with the makefile detecting the OS correctly and setting appropriate variables. The objective is to set variables for the following commands, then invoke the commands in rules using the variables: Delete file: rm in Cygwin, del in DOS. Remove directory: rmdir (different parameters in Cygwin and DOS) Copy file: cp in Cygwin, copy in DOS. Testing for file existance: test in Cygwin, IF EXIST in DOS. Listing contents of a file: cat in Cygwin, type in DOS. Here is my attempt, which always uses the else clause: OS_KIND = $(OSTYPE) #OSTYPE is an environment variable set by Cygwin. ifeq ($(OS_KIND), cygwin) ENV_OS = Cygwin RM = rm -f RMDIR = rmdir -r CP = cp REN = mv IF_EXIST = test -a IF_NOT_EXIST = ! test -a LIST_FILE = cat else ENV_OS = Win_Cmd RM = del -f -Q RMDIR = rmdir /S /Q IF_EXIST = if exist IF_NOT_EXIST = if not exist LIST_FILE = type endif I'm using the forward slash character, '/', as a directory separator. This is a problem with the DOS command, as it is interpreting it as program argument rather than a separator. Anybody know how to resolve this issue? Edit: I am using make with Mingw in both Windows Console (DOS) and Cygwin.

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  • Kohana 3 ORM: How to get data from pivot table? and all other tables for that matter

    - by zenna
    I am trying to use ORM to access data stored, in three mysql tables 'users', 'items', and a pivot table for the many-many relationship: 'user_item' I followed the guidance from http://stackoverflow.com/questions/1946357/kohana-3-orm-read-additional-columns-in-pivot-tables and tried $user = ORM::factory('user',1); $user->items->find_all(); $user_item = ORM::factory('user_item', array('user_id' => $user, 'item_id' => $user->items)); if ($user_item->loaded()) { foreach ($user_item as $pivot) { print_r($pivot); } } But I get the SQL error: "Unknown column 'user_item.id' in 'order clause' [ SELECT user_item.* FROM user_item WHERE user_id = '1' AND item_id = '' ORDER BY user_item.id ASC LIMIT 1 ]" Which is clearly erroneous because Kohana is trying to order the elements by a column which doesn't exist: user_item.id. This id doesnt exist because the primary keys of this pivot table are the foreign keys of the two other tables, 'users' and 'items'. Trying to use: $user_item = ORM::factory('user_item', array('user_id' => $user, 'item_id' => $user->items)) ->order_by('item_id', 'ASC'); Makes no difference, as it seems the order_by() or any sql queries are ignored if the second argument of the factory is given. Another obvious error with that query is that the item_id = '', when it should contain all the elements. So my question is how can I get access to the data stored in the pivot table, and actually how can I get access to the all items held by a particular user as I even had problems with that? Thanks

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  • Counting the number of objects that meets a certain criteria

    - by Candy Chiu
    The title doesn't tell the complete story. Please read the message. I have two objects: Adult and Child. Child has a boolean field isMale, and a reference to Adult. Adult doesn't reference Child. public class Adult { long id; } public class Child { long id; boolean isMale; Adult parent; } I want to create a query to list the number of sons each adult has including adults who don't have any sons. I tried: Query 1 SELECT adult, COUNT(child) FROM Child child RIGHT OUTER JOIN child.parent as adult WHERE child.isMale='true' GROUP BY adult which translates to sql select adult.id as col_0_0_, count(child.id) as col_1_0_, ... {omit properties} from Child child right outer join Adult adult on child.parentId=adult.id where child.isMale = 'true' group by adult.id Query 1 doesn't pick up adults that don't have any sons. Query 2: SELECT adult, COUNT(child.isMale) FROM Child child RIGHT OUTER JOIN child.parent as adult GROUP BY adult translates to sql: select adult.id as col_0_0_, count(child.id) as col_1_0_, ... {omit properties} from Child child right outer join Adult adult on child.parentId=adult.id group by adult.id Query 2 doesn't have the right count of sons. Basically COUNT doesn't evaluate isMale. The where clause in Query 1 filtered out Adults with no sons. How do I build a HQL or a Criteria query for this use case? Thanks.

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  • Hibernate ScrollableResults Do Not Return The Whole Set of Results

    - by mlaverd
    Some of the queries we run have 100'000+ results and it takes forever to load them and then send them to the client. So I'm using ScrollableResults to have a paged results feature. But we're topping at roughly 50k results (never exactly the same amount of results). I'm on an Oracle9i database, using the Oracle 10 drivers and Hibernate is configured to use the Oracle9 dialect. I tried with the latest JDBC driver (ojdbc6.jar) and the problem was reproduced. We also followed some advice and added an ordering clause, but the problem was reproduced. Here is a code snippet that illustrates what we do: Criteria crit = sess.createCriteria(ABC.class); crit.add(Restrictions.eq("property", value)); crit.setFetchSize(pageSize); crit.addOrder(Order.asc("property")); ScrollableResults sr = crit.scroll(); ... ... do{ for (Object entry : page) sess.evict(entry); //to avoid having our memory just explode out of proportion page.clear(); for (int i =0 ; i < pageSize && ! metLastRow; i++){ if (resultSet.next()) page.add(sr.get(0)); else metLastRow = true; } metLastRow = metLastRow?metLastRow:sr.isLast(); sendToClient(page); }while(!metLastRow); So, why is it that I get the result set to tell me its at the end when it should be having so much more results?

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  • how to get cartesian products between database and local sequences in linq?

    - by JD
    I saw this similar question here but can't figure out how to use Contains in Cartesian product desired result situation: http://stackoverflow.com/questions/1712105/linq-to-sql-exception-local-sequence-cannot-be-used-in-linq-to-sql-implementatio Let's say I have following: var a = new [] { 1, 4, 7 }; var b = new [] { 2, 5, 8 }; var test = from i in a from j in b select new { A = i, B = j, AB = string.Format("{0:00}a{1:00}b", i, j), }; foreach (var t in test) Console.Write("{0}, ", t.AB); This works great and I get a dump like so (note, I want the cartesian product): 01a02b, 01a05b, 01a08b, 04a02b, 04a05b, 04a08b, 07a02b, 07a05b, 07a08b, Now what I really want is to take this and cartesian product it again against an ID from a database table I have. But, as soon as I add in one more from clause that instead of referencing objects, references SQL table, I get an error. So, altering above to something like so where db is defined as a new DataContext (i.e., class deriving from System.Data.Linq.DataContext): var a = new [] { 1, 4, 7 }; var b = new [] { 2, 5, 8 }; var test = from symbol in db.Symbols from i in a from j in b select new { A = i, B = j, AB = string.Format("{0}{1:00}a{2:00}b", symbol.ID, i, j), }; foreach (var t in test) Console.Write("{0}, ", t.AB); The error I get is following: Local sequence cannot be used in LINQ to SQL implementations of query operators except the Contains operator Its related to not using Contains apparently but I'm unsure how Contains would be used when I don't really want to constrict the results - I want the Cartesian product for my situation. Any ideas of how to use Contains above and still yield the Cartesian product when joining database and local sequences?

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  • System.AccessViolationException when using TPT inheritance in Entity Framework CTP5

    - by Ben
    Hi, I'm using TPT inheritance in EF CTP5 with SQL CE 4. I have an abstract base class "Widget" with common properties like "Title". I can successfully save concrete Widget implementations e.g. "TwitterWidget". However, I have a problem retrieving all widgets (or rather ALL widget implementations). My repository exposes the following: public IQueryable<Widget> GetAll(); This effectively returns the IDbSet from the DbContext. The following queries work fine: repo.GetAll().ToList(); repo.GetAll().Where(w => w.Title == "Test").ToList(); repo.GetAll().SingleOrDefault(w => w.Title == "Test"); repo.GetAll().Where(w => w.Title == "Test").OrderBy(x => x.Title).ToList(); However, if I write the following query: repo.GetAll().OrderBy(w => w.Title); I get the following error: Test 'PlanetCloud.Portfolio.Tests.Data.PersistenceTestFixture.Can_get_widgets' failed: System.AccessViolationException : Attempted to read or write protected memory. This is often an indication that other memory is corrupt. at System.Data.SqlServerCe.NativeMethodsHelper.GetValues(IntPtr pSeCursor, Int32 seGetColumn, IntPtr prgBinding, Int32 cDbBinding, IntPtr pData, IntPtr pError) at System.Data.SqlServerCe.NativeMethods.GetValues(IntPtr pSeCursor, Int32 seGetColumn, IntPtr prgBinding, Int32 cDbBinding, IntPtr pData, IntPtr pError) at System.Data.SqlServerCe.SqlCeDataReader.FetchValue(Int32 index) at System.Data.SqlServerCe.SqlCeDataReader.IsDBNull(Int32 ordinal) at lambda_method(Closure , Shaper ) at System.Data.Common.Internal.Materialization.Shaper.HandleEntityAppendOnly[TEntity](Func`2 constructEntityDelegate, EntityKey entityKey, EntitySet entitySet) at lambda_method(Closure , Shaper ) at System.Data.Common.Internal.Materialization.Coordinator`1.ReadNextElement(Shaper shaper) at System.Data.Common.Internal.Materialization.Shaper`1.SimpleEnumerator.MoveNext() at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection) at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source) However, I can execute the following query without problems: var widgets = repo.GetAll().OfType<Widget>().OrderBy(w => w.Title).ToList(); So if I specify the type as the base class prior to my orderby clause it works. The question is why?

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  • ActiveRecord table inheritence using set_table_names

    - by Jinyoung Kim
    Hi, I'm using ActiveRecord in Ruby on Rails. I have a table named documents(Document class) and I want to have another table data_documents(DataDocument) class which is effectively the same except for having different table name. In other words, I want two tables with the same behavior except for table name. class DataDocument < Document #set_table_name "data_documents" self.table_name = "data_documents" end My solution was to use class inheritance as above, yet this resulted in inconsistent SQL statement for create operation where there are both 'documents' table and 'data_documents' table. Can you figure out why and how I can make it work? >> DataDocument.create(:did=>"dd") ActiveRecord::StatementInvalid: Mysql::Error: Unknown column 'data_documents.did' in 'where clause': SELECT `documents`.id FROM `documents` WHERE (`data_documents`.`did` = BINARY 'dd') LIMIT 1 from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract_adapter.rb:212:in `log' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/mysql_adapter.rb:320:in `execute' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/mysql_adapter.rb:595:in `select' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/database_statements.rb:7:in `select_all_without_query_cache' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:62:in `select_all'

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  • SQL Query - group by more than one column, but distinct

    - by Ranhiru
    I have a bidding table, as follows: SellID INT FOREIGN KEY REFERENCES SellItem(SellID), CusID INT FOREIGN KEY REFERENCES Customer(CusID), Amount FLOAT NOT NULL, BidTime DATETIME DEFAULT getdate() Now in my website I need to show the user the current bids; only the highest bid but without repeating the same user. SELECT CusID, Max(Amount) FROM Bid WHERE SellID = 10 GROUP BY CusID ORDER BY Max(Amount) DESC This is the best I have achieved so far. This gives the CusID of each user with the maximum bid and it is ordered ascending. But I need to get the BidTime for each result as well. When I try to put the BidTime in to the query: SELECT CusID, Max(Amount), BidTime FROM Bid WHERE SellID = 10 GROUP BY CusID ORDER BY Max(Amount) DESC I am told that "Column 'Bid.BidTime' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause." Thus I tried: SELECT CusID, Max(Amount), BidTime FROM Bid WHERE SellID = 10 GROUP BY CusID, BidTime ORDER BY Max(Amount) DESC But this returns all the rows. No distinction. Any suggestions on solving this issue?

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  • question about InnoDB deadlock in MySQL?

    - by WilliamLou
    I found this kind of interesting problem in MySQL InnoDB engine, could anyone explain why the engine always claim it's a deadlock. First, I created a table with a single row, single column: CREATE TABLE `SeqNum` (`current_seq_num` bigint(30) NOT NULL default '0', PRIMARY KEY (`current_seq_num`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 | Now, I have two MySQL connector threads, In thread1: mysql> begin; Query OK, 0 rows affected (0.00 sec) mysql> select `current_seq_num` into @curr_seq FROM SeqNum FOR UPDATE; Query OK, 1 row affected (0.00 sec) Now, in thread2, I did the exactly same: mysql> begin; Query OK, 0 rows affected (0.00 sec) mysql> select `current_seq_num` into @curr_seq FROM SeqNum FOR UPDATE; before the default innodb_lock_wait_timeout, the thread2 just wait for thread1 to release its exclusive lock on the table, and it's normal. However, in thread1, if I input the following update query: mysql> update SeqNum set `current_seq_num` = 8; ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction Now, thread2 get the select query finished because thread1 quits. In addition, in thread1, if I input the update query with a where clause, it can be executed very well: mysql> update SeqNum set `current_seq_num` = 8 where `current_seq_num` =5 Query OK, 1 row affected (0.00 sec) Could anyone explain this?

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  • Replicating SQL's 'Join' in Python

    - by Daniel Mathews
    I'm in the process of trying to switch from R to Python (mainly issues around general flexibility). With Numpy, matplotlib and ipython, I've am able to cover all my use cases save for merging 'datasets'. I would like to simulate SQL's join by clause (inner, outer, full) purely in python. R handles this with the 'merge' function. I've tried the numpy.lib.recfunctions join_by, but it critical issues with duplicates along the 'key': join_by(key, r1, r2, jointype='inner', r1postfix='1', r2postfix='2', defaults=None, usemask=True, asrecarray=False) Join arrays r1 and r2 on key key. The key should be either a string or a sequence of string corresponding to the fields used to join the array. An exception is raised if the key field cannot be found in the two input arrays. Neither r1 nor r2 should have any duplicates along key: the presence of duplicates will make the output quite unreliable. Note that duplicates are not looked for by the algorithm. source: http://presbrey.mit.edu:1234/numpy.lib.recfunctions.html Any pointers or help will be most appreciated!

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  • PLPGSQL : How to return a record from function executed by INSERT/UPDATE rule?

    - by seas
    Do the following scheme for my database: create sequence data_sequence; create table data_table { id integer primary key; field varchar(100); }; create view data_view as select id, field from data_table; create function data_insert(_new data_view) returns data_view as $$declare _id integer; _result data_view%rowtype; begin _id := nextval('data_sequence'); insert into data_table(id, field) values(_id, _new.field); select * into _result from data_view where id = _id; return _result; end; $$ language plpgsql; create rule insert as on insert to data_view do instead select data_insert(new); Then type in psql: insert into data_view(field) values('abc'); Would like to see something like: id | field ----+--------- 1 | abc Instead see: data_insert ------------- (1, "abc") Is it possible to fix this somehow? Thanks for any ideas. Ultimate idea is to use this in other functions, so that I could obtain id of just inserted record without selecting for it from scratch. Something like: insert into data_view(field) values('abc') returning id into my_variable would be nice but doesn't work with error: ERROR: cannot perform INSERT RETURNING on relation "data_view" HINT: You need an unconditional ON INSERT DO INSTEAD rule with a RETURNING clause. I don't really understand that HINT. I use PostgreSQL 8.4.

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  • Is there a PHP library that performs MySQL Data Validation and Sanitization According to Column Type

    - by JW
    Do you know of any open source library or framework that can perform some basic validation and escaping functionality for a MySQL Db. i envisage something along the lines of: //give it something to perform the quote() quoteInto() methods $lib->setSanitizor($MyZend_DBAdaptor); //tell it structure of the table - colnames/coltypes/ etc $lib->setTableDescription($tableDescArray); //use it to validate and escape according to coltype foreach ($prospectiveData as $colName => $rawValue) if ( $lib->isValid($colName, $rawValue)) { //add it to the set clause $setValuesArray[$lib->escapeIdentifier($colName);] = $lib->getEscapedValue($colName,$rawValue); } else { throw new Exception($colName->getErrorMessage()); } etc... I have looked into - Zend_Db_Table (which knows about a table's description), and - Zend_Db_Adaptor (which knows how to escape/sanitize values depending on TYPE) but they do not automatically do any clever stuff during updates/inserts Anyone know of a good PHP library to preform this kind of validation that I could use rather than writing my own? i envisage alot of this kind of stuff: ... elseif (eregi('^INT|^INTEGER',$dataset_element_arr[col_type])) { $datatype='int'; if (eregi('unsigned',$dataset_element_arr[col_type])) { $int_max_val=4294967296; $int_min_val=0; } else { $int_max_val=2147483647; $int_min_val=-2147483648; } } (p.s I know eregi is deprecated - its just an example of laborious code)

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  • handling java exception

    - by Noona
    This questions is related to java exception, why are there some cases that when an exception thrown the program exits even though the exception was caught and there was no exit() statement? my code looks something like this void bindProxySocket(DefaultHttpClientConnection proxyConnection, String hostName, HttpParams params) { if (!proxyConnection.isOpen()) { Socket socket = null; try { socket = new Socket(hostName, 80); } catch (UnknownHostException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } try { proxyConnection.bind(socket, params); } catch(IOException e) { System.err.println ("couldn't bind socket"); e.printStackTrace(); } } } and then I call this method like this: bindProxySocket(proxyConn, hostName, params1); but, the program exits, although I want to handle the exception by doing something else, can it be because I didn't enclose the method call within a try catch clause? what happens if I catch the exception again even though it's already in the method? and what should I do if i want to clean resources only if an exception occurs and otherwise I want to continue with the program? I am guessing in this case I have to include the whole piece of code until I can clean the resources with in a try statement or can I do it in the handle exception statement? some of these questions are on this specific case, but I would like to get a thorough answer to all my questions for future reference. thanks

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  • Bulk retrieval in HQL: could not execute native bulk manipulation query

    - by user179056
    Hello, We are getting a "could not execute native bulk manipulation query" error in HQL When we execute a query which is something like this. String query = "Select person.id from Person person where"; String bindParam = ""; List subLists = getChucnkedList(dd); for(int i = 0 ; i < subLists.size() ;i++){ bindParam = bindParam + " person.id in (:param" + i + ")"; if (i < subLists.size() - 1 ) { bindParam = bindParam + " OR " ; } } query = query + bindParam; final Query query1 = session.createQuery(query.toString()); for(int i = 0 ; i < subLists.size() ;i++){ query1.setParameterList("param" + i, subLists.get(i)); } List personIdsList = query1.list(); Basically to avoid the limit on IN clause in terms of number of ids which can be inserted (not more than 1000), we have created sublists of ids of not more than 1000 in number. We are using bind parameters to bind each sublist. However we still get error "could not execute native bulk manipulation query" How does one avoid the problem of limited parameters possible in IN query when parameters passed are more than 1000? regards Sameer

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  • Impact of ordering of correlated subqueries within a projection

    - by Michael Petito
    I'm noticing something a bit unexpected with how SQL Server (SQL Server 2008 in this case) treats correlated subqueries within a select statement. My assumption was that a query plan should not be affected by the mere order in which subqueries (or columns, for that matter) are written within the projection clause of the select statement. However, this does not appear to be the case. Consider the following two queries, which are identical except for the ordering of the subqueries within the CTE: --query 1: subquery for Color is second WITH vw AS ( SELECT p.[ID], (SELECT TOP(1) [FirstName] FROM [Preference] WHERE p.ID = ID AND [FirstName] IS NOT NULL ORDER BY [LastModified] DESC) [FirstName], (SELECT TOP(1) [Color] FROM [Preference] WHERE p.ID = ID AND [Color] IS NOT NULL ORDER BY [LastModified] DESC) [Color] FROM Person p ) SELECT ID, Color, FirstName FROM vw WHERE Color = 'Gray'; --query 2: subquery for Color is first WITH vw AS ( SELECT p.[ID], (SELECT TOP(1) [Color] FROM [Preference] WHERE p.ID = ID AND [Color] IS NOT NULL ORDER BY [LastModified] DESC) [Color], (SELECT TOP(1) [FirstName] FROM [Preference] WHERE p.ID = ID AND [FirstName] IS NOT NULL ORDER BY [LastModified] DESC) [FirstName] FROM Person p ) SELECT ID, Color, FirstName FROM vw WHERE Color = 'Gray'; If you look at the two query plans, you'll see that an outer join is used for each subquery and that the order of the joins is the same as the order the subqueries are written. There is a filter applied to the result of the outer join for color, to filter out rows where the color is not 'Gray'. (It's odd to me that SQL would use an outer join for the color subquery since I have a non-null constraint on the result of the color subquery, but OK.) Most of the rows are removed by the color filter. The result is that query 2 is significantly cheaper than query 1 because fewer rows are involved with the second join. All reasons for constructing such a statement aside, is this an expected behavior? Shouldn't SQL server opt to move the filter as early as possible in the query plan, regardless of the order the subqueries are written?

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  • Struggling with a data modeling problem

    - by rpat
    I am struggling with a data model (I use MySQL for the database). I am uneasy about what I have come up with. If someone could suggest a better approach, or point me to some reference matter I would appreciate it. The data would have organizations of many types. I am trying to do a 3 level classification (Class, Category, Type). Say if I have 'Italian Restaurant', it will have the following classification Food Services Restaurants Italian However, an organization may belong to multiple groups. A restaurant may also serve Chinese and Italian. So it will fit into 2 classifications Food Services Restaurants Italian Food Services Restaurants Chinese The classification reference tables would be like the following: ORG_CLASS (RowId, ClassCode, ClassName) 1, FOOD, Food Services ORG_CATEGORY(RowId, ClassCode, CategoryCode, CategoryName) 1, FOOD, REST, Restaurants ORG_TYPE (RowId, ClassCode, CategoryCode, TypeCode, TypeName) 100, FOOD, REST, ITAL, Italian 101, FOOD, REST, CHIN, Chinese 102, FOOD, REST, SPAN, Spanish 103, FOOD, REST, MEXI, Mexican 104, FOOD, REST, FREN, French 105, FOOD, REST, MIDL, Middle Eastern The actual data tables would be like the following: I will allow an organization a max of 3 classifications. I will have 3 GroupIds each pointing to a row in ORG_TYPE. So I have my ORGANIZATION_TABLE ORGANIZATION_TABLE (OrgGroupId1, OrgGroupId2, OrgGroupId3, OrgName, OrgAddres) 100,103,NULL,MyRestaurant1, MyAddr1 100,102,NULL,MyRestaurant2, MyAddr2 100,104,105, MyRestaurant3, MyAddr3 During data add, a dialog could let the user choose the clssa, category, type and the corresponding GroupId could be populated with the rowid from the ORG_TYPE table. During Search, If all three classification are chosen, It will be more specific. For example, if Food Services Restaurants Italian is the criteria, the where clause would be 'where OrgGroupId1 = 100' If only 2 levels are chosen Food Services Restaurants I have to do 'where OrgGroupId1 in (100,101,102,103,104,105, .....)' - There could be a hundred in that list I will disallow class level search. That is I will force selection of a class and category The Ids would be integers. I am trying to see performance issues and other issues. Overall, would this work? or I need to throw this out and start from scratch.

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  • Converting a Linq expression tree that relies on SqlMethods.Like() for use with the Entity Framework

    - by JohnnyO
    I recently switched from using Linq to Sql to the Entity Framework. One of the things that I've been really struggling with is getting a general purpose IQueryable extension method that was built for Linq to Sql to work with the Entity Framework. This extension method has a dependency on the Like() method of SqlMethods, which is Linq to Sql specific. What I really like about this extension method is that it allows me to dynamically construct a Sql Like statement on any object at runtime, by simply passing in a property name (as string) and a query clause (also as string). Such an extension method is very convenient for using grids like flexigrid or jqgrid. Here is the Linq to Sql version (taken from this tutorial: http://www.codeproject.com/KB/aspnet/MVCFlexigrid.aspx): public static IQueryable<T> Like<T>(this IQueryable<T> source, string propertyName, string keyword) { var type = typeof(T); var property = type.GetProperty(propertyName); var parameter = Expression.Parameter(type, "p"); var propertyAccess = Expression.MakeMemberAccess(parameter, property); var constant = Expression.Constant("%" + keyword + "%"); var like = typeof(SqlMethods).GetMethod("Like", new Type[] { typeof(string), typeof(string) }); MethodCallExpression methodExp = Expression.Call(null, like, propertyAccess, constant); Expression<Func<T, bool>> lambda = Expression.Lambda<Func<T, bool>>(methodExp, parameter); return source.Where(lambda); } With this extension method, I can simply do the following: someList.Like("FirstName", "mike"); or anotherList.Like("ProductName", "widget"); Is there an equivalent way to do this with Entity Framework? Thanks in advance.

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  • php $_FILES error code returning an unexpected error

    - by EmmyS
    I have some code that allows users to upload multiple files at once. It was never getting to a specific point after the upload, so I put in an echo to test for the value of the error code, and it's returning a value that I'm not sure I understand. Here's the code: $tmpTarget = PCBUG_UPLOADPATH; foreach ($_FILES["attachments"]["error"] as $key => $error) { if ($error == UPLOAD_ERR_OK) { $tmp_name = $_FILES["attachments"]["tmp_name"][$key]; $name = str_replace(" ", "_", $_FILES["attachments"]["name"][$key]); move_uploaded_file($tmp_name, "$tmpTarget/$name"); @unlink($_FILES["attachments"]["tmp_name"][$key]); } else { $errorFlag = true; echo "error = $error"; exit; } } The code that creates the attachments field looks like this: for($i=1; $i<=$max_no_img; $i++){ echo "<input type=file name='attachments[]' class='bginput'><br />"; } where $max_no_img is a variable set further up in the code, and PCBUG_UPLOAD path is a constant defined in an included file. Here's what's confusing: after I submit my form, I go and look in my uploads directory, and the files I've selected through the form are there - they uploaded correctly. However, the code is jumping into the else clause and $error is returning 4, which the php manual indicates means that no file was uploaded. Any ideas? The files very clearly are getting where they're supposed to. Is there some other definition of "uploaded" that isn't happening?

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  • Do programmers need a union?

    - by James A. Rosen
    In light of the acrid responses to the intellectual property clause discussed in my previous question, I have to ask: why don't we have a programmers' union? There are many issues we face as employees, and we have very little ability to organize and negotiate. Could we band together with the writers', directors', or musicians' guilds, or are our needs unique? Has anyone ever tried to start one? If so, why did it fail? (Or, alternatively, why have I never heard of it, despite its success?) later: Keith has my idea basically right. I would also imagine the union being involved in many other topics, including: legal liability for others' use/misuse of our work, especially unintended uses evaluating the quality of computer science and software engineering higher education programs -- unlike many other engineering disciplines, we are not required to be certified on receiving our Bachelor's degrees evangelism and outreach -- especially to elementary school students certification -- not doing it, but working with the companies like ISC(2) and others to make certifications meaningful and useful continuing education -- similar to previous conferences -- maintain a go-to list of organizers and other resources our members can use I would see it less so as a traditional trade union, with little emphasis on: pay -- we tend to command fairly good salaries outsourcing and free trade -- most of use tend to be pretty free-market oriented working conditions -- we're the only industry with Aeron chairs being considered anything like "standard"

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  • Catching a nested-in-template exception [C++]

    - by Karol
    Hello, I have a problem with writing a catch clause for an exception that is a class nested in a template. To be more specific, I have a following definition of the template and exception: /** Generic stack implementation. Accepts std::list, std::deque and std::vector as inner container. */ template < typename T, template < typename Element, typename = std::allocator<Element> > class Container = std::deque > class stack { public: class StackEmptyException { }; ... /** Returns value from the top of the stack. Throws StackEmptyException when the stack is empty. */ T top() const; ... } I have a following template method that I want exception to catch: template <typename Stack> void testTopThrowsStackEmptyExceptionOnEmptyStack() { Stack stack; std::cout << "Testing top throws StackEmptyException on empty stack..."; try { stack.top(); } catch (Stack::StackEmptyException) { // as expected. } std::cout << "success." << std::endl; } When I compile it (-Wall, -pedantic) I get the following error: In function ‘void testTopThrowsStackEmptyExceptionOnEmptyStack()’: error: expected type-specifier error: expected unqualified-id before ‘)’ token === Build finished: 2 errors, 0 warnings === Thanks in advance for any help! What is interesting, if the stack implementation was not a template, then the compiler would accept the code as it is.

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  • Linq join with an inner collection

    - by bronze
    Hi, I am trying a LINQ to Object query on 2 collections Customer.Orders Branches.Pending.Orders (Collection within a collection) I want to output each branch which is yet to deliver any order of the customer. var match = from order in customer.Orders join branch in Branches on order equals branch.Pending.Orders select branch; This does not work, I get : The type of one of the expressions in the join clause is incorrect. Type inference failed in the call to 'GroupJoin'. From my search, I think this is because Order or collection of Orders does not implement equals. If this query worked, it will still be wrong, as it will return a branch if the customer's and pending orders match exactly. I want a result if any of the order matches. I am learning Linq, and looking for a approach to address such issues, rather than the solution itself. I would have done this in SQL like this; SELECT b.branch_name from Customers c, Branches b, Orders o WHERE c.customer_id = o.customer_id AND o.branch_id = b.branch_id AND c.customer_id = 'my customer' AND o.order_status = 'pending'

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  • strange syntax error in python, version 2.6 and 3.1

    - by flow
    this may not be an earth-shattering deficiency of python, but i still wonder about the rationale behind the following behavior: when i run source = """ print( 'helo' ) if __name__ == '__main__': print( 'yeah!' ) #""" print( compile( source, '<whatever>', 'exec' ) ) i get :: File "<whatever>", line 6 # ^ SyntaxError: invalid syntax i can avoid this exception by (1) deleting the trailing #; (2) deleting or outcommenting the if __name__ == '__main__':\n print( 'yeah!' ) lines; (3) add a newline to very end of the source. moreover, if i have the source end without a trailing newline right behind the print( 'yeah!' ), the source will also compile without error. i could also reproduce this behavior with python 2.6, so it’s not new to the 3k series. i find this error to be highly irritating, all the more since when i put above source inside a file and execute it directly or have it imported, no error will occur—which is the expected behavior. a # (hash) outside a string literal should always represent the start of a (possibly empty) comment in a python source; moreover, the presence or absence of a if __name__ == '__main__' clause should not change the interpretation of a soure on a syntactical level. can anyone reproduce the above problem, and/or comment on the phenomenon? cheers

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