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  • Why can't I inherit static classes?

    - by User
    I have several classes that do not really need any state. From the organizational point of view, I would like to put them into hierarchy. But it seems I can't declare inheritance for static classes. Something like that: public static class Base { } public static class Inherited : Base { } will not work. Why have the designers of the language closed that possibility?

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  • Oracle 10g - Best way to escape single quotes

    - by satynos
    I have to generate some update statements based off a table in our database. I created the following script which is generating the update statements I need. But when I try to run those scripts I am getting errors pertaining to unescaped single quotes in the content and &B, &T characters which have special meaning in oracle. I took care of the &B and &T problem by setting SET DEFINE OFF. Whats the best way to escape single quotes within the content? DECLARE CURSOR C1 IS SELECT * FROM EMPLOYEES; BEGIN FOR I IN C1 LOOP DBMS_OUTPUT.PUT_LINE('UPDATE EMPLOYEES SET FIRST_NAME= ''' || I.FIRST_NAME|| ''', LAST_NAME = ''' || I.LAST_NAME ''', DOB = ''' || I.DOB|| ''' WHERE EMPLOYEE_ID = ''' || I.EMPLOYEE_ID || ''';'); END LOOP; END; Here if the first_name or last_name contains single quotes then the generated update statements break. Whats the best way to escape those single quotes within the first_name and last_name?

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  • Linq 2 SQL Store inherited classes - not mapped to tables in the database

    - by user348672
    Hi. I'm trying to introduce the Linq2SQL technique into the project and have encountered the following issue: I've created ORM classes based on the Northwind database. In some other application I create several classes derived from the Linq2SQL classes. I'm able to add such a class to EntitySet but the application fails to submit changes. Is there any way around this? Sample code(MyClass is derived from the Order): DataClasses1DataContext northwind = new DataClasses1DataContext(); Product chai = northwind.Products.Single(p => p.ProductName == "Chai"); Product tofu = northwind.Products.Single(p => p.ProductName == "Tofu"); Order myOrder = new Order(); myOrder.OrderDate = DateTime.Now; myOrder.RequiredDate = DateTime.Now.AddDays(1); myOrder.Freight = 34; Order_Detail myItem1 = new Order_Detail(); myItem1.Product = chai; myItem1.Quantity = 12345; Order_Detail myItem2 = new Order_Detail(); myItem2.Product = tofu; myItem2.Quantity = 3; myOrder.Order_Details.Add(myItem1); myOrder.Order_Details.Add(myItem2); Customer myCustomer = northwind.Customers.Single(c => c.CompanyName == "B's Beverages"); MyClass newOrder = new MyClass(); newOrder.OrderDate = DateTime.Now; newOrder.RequiredDate = DateTime.Now.AddDays(31); newOrder.Freight = 35; Order_Detail myItem3 = new Order_Detail(); myItem3.Product = tofu; myItem3.Quantity = 3; newOrder.Order_Details.Add(myItem3); myCustomer.Orders.Add(myOrder); myCustomer.Orders.Add(newOrder); As I said I'm able to add the newOrder object but unable to submit into the database.

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  • Internet Explorer table 1 pixel spacing problem

    - by Dennis G.
    I've found a strange problem with Internet Explorer related to table spacing and cannot find a way to work around it. An empty table results in a single pixel white space with Internet Explorer (6 and 7, 8 not yet tested), while all other browsers ignore the empty table. Here's a picture of the problem: And here is the minimum HTML code to reproduce the issue (please note that there are more margin/padding css attributes and table attributes specified than really needed, I just tested if this fixes IE's behavior): <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <body> <div style="width: 200px; border: 1px black solid"> <table border="0" cellspacing="0" cellpadding="0" style="margin: 0pt; padding: 0pt; border-collapse: collapse;"> <tr> <td style="padding: 0; margin: 0"> </td> </tr> </table> <div style="background: red"> Test </div> </div> </body> </html> I'm not using an empty table as specified in the example above, but this was the minimum code that displays this behavior. Any ideas on how to fix this and remove the white space with IE?

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  • Convert multiple eml files to single PST in C#

    - by Ayesha
    I need to write a single function which will take multiple eml files ( may be from a single filesystem folder ) and convert them to a single PST file. Is it possible? if yes can someone provide a sample code? I assume its possible because there are many commercial eml to pst converters out there doing this

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  • Table and Image in a single page of QTextDocument in Qt4

    - by liaK
    Hi, I want to display a table and a image side by side. i.e Left side the image and right side the table. I want this because the image is the reference image for the data present in the table. I want that output in pdf. So I am using QTextDocument, QTextCursor and QPrinter to get the output in pdf. So how it is possible to display the image and table in QtextDocument i.e within a single page of the pdf? I am using Qt 4.5.3 and Windows Xp. Any pointers regarding this are welcome.

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  • JCombobox containing enum values inside a table

    - by Edan
    Hello, I have a class containing Enum with values. (names) In other class I would like to enter inside a table a cell type of JCombobox that will use these enums values. my problem is to combain between string values and the enum. for example the enum class: enum item_Type {entree, main_Meal, Dessert, Drink} for example the table class: setTitle("Add new item" ); setSize(300, 80); setBackground( Color.gray ); // Create a panel to hold all other components topPanel = new JPanel(); topPanel.setLayout( new BorderLayout() ); getContentPane().add( topPanel ); //new JComboBox(item_Type.values()); JComboBox aaa = new JComboBox(); aaa = new JComboBox(item_Type.values()); TableColumn sportColumn = table.getColumnModel().getColumn(2); // Create columns names String columnNames[] = {"Item Description", "Item Type", "Item Price"}; // Create some data String dataValues[][] = {{ "0", aaa, "0" }}; // Create a new table instance table = new JTable( dataValues, columnNames ); // Add the table to a scrolling pane scrollPane = new JScrollPane( table ); topPanel.add( scrollPane, BorderLayout.CENTER ); I know that at the dataValues array I cant use aaa (the enum jcombobox). How can I do that? thanks in advance.

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  • Jquery problem - cant expand the row above in a table

    - by apg1985
    Hi People, What I cant figure out is how I would toggle a row in a table using the one below it. So say I have a table with 2 rows the first contains content and the one below contains a button, when the page loads the content row is hidden and when you click the button it toggles the content row on and off. In the example the first table works but the second does not, I need the second one to work. <!DOCTYPE HTML> <html> <head> <title>Testing Horizontal Accordion</title> <script type="text/javascript" src="jquery.js"></script> <script type="text/javascript"> $(document).ready(function() { $(".sectionhead").toggle( function() { $(this).next("tr").hide(); }, function() { $(this).next("tr").show(); } ) }); </script> </head> <body> <table> <tr class="sectionhead"><td></td></tr> <tr class="child"><td>child</td></tr> </table> <br> <table> <tr class="child"><td>child</td></tr> <tr class="sectionhead"><td></td></tr> </table> </body> </html>

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  • Finding the right terminology for a dictionary table

    - by Karl Forner
    My concern is about what I currently call "dictionary tables", that are database tables containing a list of controlled vocabulary. Let's use an example: Suppose you have a table User containing fields: user_id : primary key first_name last_name user_type_id : foreign key to the UserType table and another table UserType with just two fields: user_type_id : primary key name : the name/value of a particular type of user. For instance, the UserType table may contain (1, Administrator), (2, PowerUser), (3, Normal)... My question is: what is the canonical term for a table like UserType, that only contains a list of (dictinct) words. I want to publish some code that help managing this kind of tables, but first I have to name them ! Thanks for your help. Current state of thought: For now I feel Lookup Tables is a good term. It is also used with the same meaning in these posts: http://dbix-class.35028.n2.nabble.com/RFC-Component-for-Lookup-tables-td3504085.html http://tonyandrews.blogspot.de/2004/10/otlt-and-eav-two-big-design-mistakes.html Lookup Tables Best Practices: DB Tables... or Enumerations The only problem is that lookup table is also sometimes used to name a junction table.

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  • Double-tap or two single-taps?

    - by Jaka Jancar
    What is the time limit for two taps to be considered a double-tap, on the iPhone OS? // Edit: Why is this important? In order to handle single-tap and double-tap differently, Apple's guide says to do performSelector...afterDelay with some 'reasonable' interval on first tap (and cancel it later if the second tap is detected). The problem is that if the interval is too short (0.1), the single tap action will be performed even when double-tapping (if relying only on tapCount, that is). If it's too long (0.8), the user will be waiting unnecessarily for the single-tap to be recognized, when there is no possibility for a double-tap. It has to be exactly the correct number, in order to work optimally, but definitely not smaller, or there's a chance for bugs (simultaneous single-tap and double-tap).

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  • Performance impact when using XML columns in a table with MS SQL 2008

    - by Sam Dahan
    I am using a simple table with 6 columns, 3 of which are of XML type, not schema-constrained. When the table reaches a size around 120,000 or 150,000 rows, I see a dramatic performance cost in doing any query in the table. For comparison, I have another table, which grows in size at about the same rate, but only contain scalar types (int, datetime, a few float columns). That table performs perfectly fine even after 200,000 rows. And by the way, I am not using XQuery on the xml columns, i am only using regular SQL query statements. Some specifics: both tables contain a DateTime field called SampleTime. a statement like (it's in a stored procedure but I show you the actual statement) SELECT MAX(sampleTime) SampleTime FROM dbo.MyRecords WHERE PlacementID=@somenumber takes 0 seconds on the table without xml columns, and anything from 13 to 20 seconds on the table with XML columns. That depends on which drive I set my database on. At the moment it sits on a different spindle (not C:) and it takes 13 seconds. Has anyone seen this behavior before, or have any hint at what I am doing wrong? I tried this with SQL 2008 EXPRESS and the full-blown SQL Server 2008, that made no difference. Oh, one last detail: I am doing this from a C# application, .NET 3.5, using SqlConnection, SqlReader, etc.. I'd appreciate some insight into that, thanks! Sam

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  • Problem with extending JPanel

    - by Halo
    I have an abstract entity: public abstract class Entity extends JPanel implements FocusListener And I have a TextEntity: public class TextEntity extends Entity Inside TextEntity's constructor I want to put a JTextArea that will cover the panel: textArea = new JTextArea(); textArea.setSize(getWidth(),getHeight()); add(textArea); But getWidth() and getHeight() returns 0. Is it a problem with the inheritance or the constructor?

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  • MySQL: Complex Join Statement involving two tables and a third correlation table

    - by Stephen
    I have two tables that were built for two disparate systems. I have records in one table (called "leads") that represent customers, and records in another table (called "manager") that are the exact same customers but "manager" uses different fields (For example, "leads" contains an email address, and "manager" contains two fields for two different emails--either of which might be the email from "leads"). So, I've created a correlation table that contains the lead_id and manager_id. currently this correlation table is empty. I'm trying to query the "leads" table to give me records that match either "manager" email field with the single "leads" email field, while at the same time ignoring fields that have already been added to the "correlated" table. (this way I can see how many leads that match have not yet been correlated.) Here's my current, invalid SQL attempt: SELECT leads.id, manager.id FROM leads, manager LEFT OUTER JOIN correlation ON correlation.lead_id = leads.id WHERE correlation.id IS NULL AND leads.project != "someproject" AND (manager.orig_email = leads.email OR manager.dest_email = leads.email) AND leads.created BETWEEN '1999-01-01 00:00:00' AND '2010-05-10 23:59:59' ORDER BY leads.created ASC; I get the error: Unknown column 'leads.id' in 'on clause' Before you wonder: there are records in the "leads" table where leads.project != "someproject" and leads.created falls between those dates. I've included those additional parameters for completeness.

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  • SQL: Order randomly when inserting objects to a table

    - by Ekaterina
    I have an UDF that selects top 6 objects from a table (with a union - code below) and inserts it into another table. (btw SQL 2005) So I paste the UDF below and what the code does is: selects objects for a specific city and add a level to those (from table Europe) union that selection with a selection from the same table for objects that are from the same country and add a level to those From the union, selection is made to get top 6 objects, order by level, so the objects from the same city will be first, and if there aren't any available, then objects from the same country will be returned from the selection. And my problem is, that I want to make a random selection to get random objects from table Europe, but because I insert the result of my selection into a table, I can't use order by newid() or rand() function because they are time-dependent, so I get the following errors: Invalid use of side-effecting or time-dependent operator in 'newid' within a function. Invalid use of side-effecting or time-dependent operator in 'rand' within a function. UDF: ALTER FUNCTION [dbo].[Objects] (@id uniqueidentifier) RETURNS @objects TABLE ( ObjectId uniqueidentifier NOT NULL, InternalId uniqueidentifier NOT NULL ) AS BEGIN declare @city varchar(50) declare @country int select @city = city, @country = country from Europe where internalId = @id insert @objects select @id, internalId from ( select distinct top 6 [level], internalId from ( select top 6 1 as [level], internalId from Europe N4 where N4.city = @city and N4.internalId != @id union select top 6 2 as [level], internalId from Europe N5 where N5.countryId = @country and N5.internalId != @id ) as selection_1 order by [level] ) as selection_2 return END If you have fresh ideas, please share them with me. (Just please, don't suggest to order by newid() or to add a column rand() with seed DateTime (by ms or sthg), because that won't work.)

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  • Escape doube and single backslashes in a string in Ruby

    - by Nick Gorbikoff
    Hello. I'm trying to access a network path in my ruby script on a windows platform in a format like this. \\servername\some windows share\folder 1\folder2\ Now If I try to use this as a path, it won't work. Single backslashes are not properly escaped for this script. path = "\\servername\some windows share\folder 1\folder2\" d = Dir.new(path) I tried everything I could think of to properly escape slashes in the path. However I can't escape that single backslash - because of it's special meaning. I tried single quotes, double quotes, escaping backslash itself, using alternate quotes such as %Q{} or %q{}, using ascii to char conversion. Nothing works in a sense that I'm not doing it right. :-) Right now the temp solution is to Map a network drive N:\ pointing to that path and access it that way, but that not a solution. Does anyone have any idea how to properly escape single backslashes? Thank you

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  • Data Access from single table in sql server 2005 is too slow

    - by Muhammad Kashif Nadeem
    Following is the script of table. Accessing data from this table is too slow. SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[Emails]( [id] [int] IDENTITY(1,1) NOT NULL, [datecreated] [datetime] NULL CONSTRAINT [DF_Emails_datecreated] DEFAULT (getdate()), [UID] [nvarchar](250) COLLATE Latin1_General_CI_AS NULL, [From] [nvarchar](100) COLLATE Latin1_General_CI_AS NULL, [To] [nvarchar](100) COLLATE Latin1_General_CI_AS NULL, [Subject] [nvarchar](max) COLLATE Latin1_General_CI_AS NULL, [Body] [nvarchar](max) COLLATE Latin1_General_CI_AS NULL, [HTML] [nvarchar](max) COLLATE Latin1_General_CI_AS NULL, [AttachmentCount] [int] NULL, [Dated] [datetime] NULL ) ON [PRIMARY] Following query takes 50 seconds to fetch data. select id, datecreated, UID, [From], [To], Subject, AttachmentCount, Dated from emails If I include Body and Html in select then time is event worse. indexes are on: id unique clustered From Non unique non clustered To Non unique non clustered Tabls has currently 180000+ records. There might be 100,000 records each month so this will become more slow as time will pass. Does splitting data into two table will solve the problem? What other indexes should be there?

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  • Partial class or "chained inheritance"

    - by Charlie boy
    Hi From my understanding partial classes are a bit frowned upon by professional developers, but I've come over a bit of an issue; I have made an implementation of the RichTextBox control that uses user32.dll calls for faster editing of large texts. That results in quite a bit of code. Then I added spellchecking capabilities to the control, this was made in another class inheriting RichTextBox control as well. That also makes up a bit of code. These two functionalities are quite separate but I would like them to be merged so that I can drop one control on my form that has both fast editing capabilities and spellchecking built in. I feel that simply adding the code form one class to the other would result in a too large code file, especially since there are two very distinct areas of functionality, so I seem to need another approach. Now to my question; To merge these two classes should I make the spellchecking RichTextBox inherit from the fast edit one, that in turn inherits RichTextBox? Or should I make the two classes partials of a single class and thus making them more “equal” so to speak? This is more of a question of OO principles and exercise on my part than me trying to reinvent the wheel, I know there are plenty of good text editing controls out there. But this is just a hobby for me and I just want to know how this kind of solution would be managed by a professional. Thanks!

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  • How to update a single table using trigger in MS SQL 2008

    - by Yakob-Jack
    I have a table PeroidicDeduction and the fields are ID(auto-increment),TotalDeduction(e.g.it can be loan),Paid(on which the deduction for each month),RemainingAmount, What I want is when every time I insert or update the table---RemainingAmount will get the value of TotalDeduction-SUM(Paid)....and writ the following trigger...but dosen't work for me CREATE TRIGGER dbo.UpdatePD ON PeroidicDedcution AFTER INSERT,UPDATE AS BEGIN UPDATE PeroidicDedcution SET REmaininAmoubnt=(SELECT TotalDeduction-(SELECT SUM(Paid) FROM PeroidicDeduction) FROM PeroidicDeduction) END NOTE: it is on a Single table

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  • how to implement single sign on for asp.net,mysql websites

    - by kranthi
    Hi, I am using mysql database for my asp.net website.I need to implement to single sign on for multiple instances of my website.Currently to check if a user has logged in I am using a user control which checks for a "loggedin" cookie with single instance of the website.Now I need to extend the logic to achieve single signon for multiple instances of the same site. Could someone please help. Thanks.

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  • Handling inheritance with overriding efficiently

    - by Fyodor Soikin
    I have the following two data structures. First, a list of properties applied to object triples: Object1 Object2 Object3 Property Value O1 O2 O3 P1 "abc" O1 O2 O3 P2 "xyz" O1 O3 O4 P1 "123" O2 O4 O5 P1 "098" Second, an inheritance tree: O1 O2 O4 O3 O5 Or viewed as a relation: Object Parent O2 O1 O4 O2 O3 O1 O5 O3 O1 null The semantics of this being that O2 inherits properties from O1; O4 - from O2 and O1; O3 - from O1; and O5 - from O3 and O1, in that order of precedence. NOTE 1: I have an efficient way to select all children or all parents of a given object. This is currently implemented with left and right indexes, but hierarchyid could also work. This does not seem important right now. NOTE 2: I have tiggers in place that make sure that the "Object" column always contains all possible objects, even when they do not really have to be there (i.e. have no parent or children defined). This makes it possible to use inner joins rather than severely less effiecient outer joins. The objective is: Given a pair of (Property, Value), return all object triples that have that property with that value either defined explicitly or inherited from a parent. NOTE 1: An object triple (X,Y,Z) is considered a "parent" of triple (A,B,C) when it is true that either X = A or X is a parent of A, and the same is true for (Y,B) and (Z,C). NOTE 2: A property defined on a closer parent "overrides" the same property defined on a more distant parent. NOTE 3: When (A,B,C) has two parents - (X1,Y1,Z1) and (X2,Y2,Z2), then (X1,Y1,Z1) is considered a "closer" parent when: (a) X2 is a parent of X1, or (b) X2 = X1 and Y2 is a parent of Y1, or (c) X2 = X1 and Y2 = Y1 and Z2 is a parent of Z1 In other words, the "closeness" in ancestry for triples is defined based on the first components of the triples first, then on the second components, then on the third components. This rule establishes an unambigous partial order for triples in terms of ancestry. For example, given the pair of (P1, "abc"), the result set of triples will be: O1, O2, O3 -- Defined explicitly O1, O2, O5 -- Because O5 inherits from O3 O1, O4, O3 -- Because O4 inherits from O2 O1, O4, O5 -- Because O4 inherits from O2 and O5 inherits from O3 O2, O2, O3 -- Because O2 inherits from O1 O2, O2, O5 -- Because O2 inherits from O1 and O5 inherits from O3 O2, O4, O3 -- Because O2 inherits from O1 and O4 inherits from O2 O3, O2, O3 -- Because O3 inherits from O1 O3, O2, O5 -- Because O3 inherits from O1 and O5 inherits from O3 O3, O4, O3 -- Because O3 inherits from O1 and O4 inherits from O2 O3, O4, O5 -- Because O3 inherits from O1 and O4 inherits from O2 and O5 inherits from O3 O4, O2, O3 -- Because O4 inherits from O1 O4, O2, O5 -- Because O4 inherits from O1 and O5 inherits from O3 O4, O4, O3 -- Because O4 inherits from O1 and O4 inherits from O2 O5, O2, O3 -- Because O5 inherits from O1 O5, O2, O5 -- Because O5 inherits from O1 and O5 inherits from O3 O5, O4, O3 -- Because O5 inherits from O1 and O4 inherits from O2 O5, O4, O5 -- Because O5 inherits from O1 and O4 inherits from O2 and O5 inherits from O3 Note that the triple (O2, O4, O5) is absent from this list. This is because property P1 is defined explicitly for the triple (O2, O4, O5) and this prevents that triple from inheriting that property from (O1, O2, O3). Also note that the triple (O4, O4, O5) is also absent. This is because that triple inherits its value of P1="098" from (O2, O4, O5), because it is a closer parent than (O1, O2, O3). The straightforward way to do it is the following. First, for every triple that a property is defined on, select all possible child triples: select Children1.Id as O1, Children2.Id as O2, Children3.Id as O3, tp.Property, tp.Value from TriplesAndProperties tp -- Select corresponding objects of the triple inner join Objects as Objects1 on Objects1.Id = tp.O1 inner join Objects as Objects2 on Objects2.Id = tp.O2 inner join Objects as Objects3 on Objects3.Id = tp.O3 -- Then add all possible children of all those objects inner join Objects as Children1 on Objects1.Id [isparentof] Children1.Id inner join Objects as Children2 on Objects2.Id [isparentof] Children2.Id inner join Objects as Children3 on Objects3.Id [isparentof] Children3.Id But this is not the whole story: if some triple inherits the same property from several parents, this query will yield conflicting results. Therefore, second step is to select just one of those conflicting results: select * from ( select Children1.Id as O1, Children2.Id as O2, Children3.Id as O3, tp.Property, tp.Value, row_number() over( partition by Children1.Id, Children2.Id, Children3.Id, tp.Property order by Objects1.[depthInTheTree] descending, Objects2.[depthInTheTree] descending, Objects3.[depthInTheTree] descending ) as InheritancePriority from ... (see above) ) where InheritancePriority = 1 The window function row_number() over( ... ) does the following: for every unique combination of objects triple and property, it sorts all values by the ancestral distance from the triple to the parents that the value is inherited from, and then I only select the very first of the resulting list of values. A similar effect can be achieved with a GROUP BY and ORDER BY statements, but I just find the window function semantically cleaner (the execution plans they yield are identical). The point is, I need to select the closest of contributing ancestors, and for that I need to group and then sort within the group. And finally, now I can simply filter the result set by Property and Value. This scheme works. Very reliably and predictably. It has proven to be very powerful for the business task it implements. The only trouble is, it is awfuly slow. One might point out the join of seven tables might be slowing things down, but that is actually not the bottleneck. According to the actual execution plan I'm getting from the SQL Management Studio (as well as SQL Profiler), the bottleneck is the sorting. The problem is, in order to satisfy my window function, the server has to sort by Children1.Id, Children2.Id, Children3.Id, tp.Property, Parents1.[depthInTheTree] descending, Parents2.[depthInTheTree] descending, Parents3.[depthInTheTree] descending, and there can be no indexes it can use, because the values come from a cross join of several tables. EDIT: Per Michael Buen's suggestion (thank you, Michael), I have posted the whole puzzle to sqlfiddle here. One can see in the execution plan that the Sort operation accounts for 32% of the whole query, and that is going to grow with the number of total rows, because all the other operations use indexes. Usually in such cases I would use an indexed view, but not in this case, because indexed views cannot contain self-joins, of which there are six. The only way that I can think of so far is to create six copies of the Objects table and then use them for the joins, thus enabling an indexed view. Did the time come that I shall be reduced to that kind of hacks? The despair sets in.

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