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Since 1998, DevX has helped people start businesses, build websites, and provide enterprise technology to people globally. Interviewing the likes of Microsoft’s co-founder, Steve Ballmer, the publication brings comprehensive, reliable, and accessible insights to the Internet.
Let’s take an example: a program has a PrintSpooler class. This class maintains a queue for printer requests and serializes them. The program cannot contain multiple PrintSpooler Objects because this
The PrettyPrinter Add-in is a very simple VB5 and VB6 add-in that lets you print whole VB code modules or selected procedures, in both portrait or landscape mode. While the
VB now allows us to addcontrols to a Form at run time. In thisarticle I will try to explain a way in which you can dynamically add a control arrayto
n my series of articles, “Paranoid and Proud of It,” I pointed out that systems require different backup strategies, depending on the criticality of the information stored in them. SQL
he task of retrieving the top or bottom N rows from a database table (by salary, sales amount, credit, etc.) is often referred to as a “top-N query.” This task
n last month’s article I showed you how to create a calendar page in ASP with pop-up functionality. In this month’s article, I’ll show you how to make your pop-up
If you want to show online help (HTML Pages or images) through your applet by clicking the Help button or the F1 key or some other icon, you have to
Many C++ programmers will be familiar with the tidal wave of recompilations that occur when a seemingly unrelated header file is changed. C++ file dependencies need to be managed otherwise
Many C++ programmers will be familiar with the tidal wave of recompilations that occur when a seemingly unrelated header file is changed. C++ file dependencies need to be managed otherwise
There are two undocumented encryption functions. They are not supported by Microsoft, and I have had problems with some SQL Server service packs when using these functions. That being said,
By default, SQL Server 7.0 installation sets up SQL Server to run in a case insensitive mode. For most applications this may work great, but there are certain situations were
Certain applications require business logic to determine the last day of the month. This is the case for accounting applications that perform such tasks as invoice processing and customer billing.
When tuning SQL Server applications, a certain degree of hands-on experimenting must occur. Index options, table design, and locking options are items that can be modified to increase performance. When
Whenever a client application needs to send Transact-SQL to SQL Server, send it in the form of a stored procedure instead of a script or dynamic Transact-SQL. This not only
When a stored procedure is first executed (and it does not have the WITH RECOMPILE option), it is optimized and a query plan is compiled and cached in SQL Server’s
The new INSTEAD OF functionality is not exactly like a trigger, but similar. Unlike AFTER triggers, the INSTEAD OF trigger replaces the incoming transaction data modification statement with its own
Orphan SQL Server connections can decrease SQL Server performance. An orphan connection occurs when SQL Server keeps the connection open, even though it is not being used. There are two
This tip is for when you want to place an action after a time gap between two occurrences (for example, to invalidate an unused session after some permitted time, or
Depending on the version of Windows targeted, there are two different ways to run a VB application during the boot process.Under Windows 9x systems, place a Shell command in the
Private Declare Function LogonUser Lib “Advapi32” Alias “LogonUserA” (ByVal _ lpszUserName As String, ByVal lpszDomain As String, _ ByVal lpszPassword As String, ByVal dwLogonType As Long, _ ByVal dwLogonProvider As
Encapsulation is a fundamental principle in object orientation. Encapsulation restricts direct access to a data member of a class. Instead, users query the object itself in order to get or
Look at the following program. It compiles correctly under every standard-conforming compiler. At first, this may seem surprising because seemingly, because it’s impossible delete an object which is not a
The auto_ptr class template respects polymorphism and destroys derived objects of base pointers properly. In the following program, an auto_ptr is actually bound to a B * pointer, where B
A function call such as the following: classname::funcname(); is a qualified call. Qualified disambiguate function names. They are needed, for instance, in a class that inherits from several base classes,
Here’s a very common error. You define a class but forgot to add a semicolon after the closing }. For example: class Mylist{public: Mylist(); ~Mylist(); //..more member functions} // missing
Because static class members are not associated with a particular object of their class, you can access them even if you haven’t instantiated any object. In the following example, the
The escape sequence ‘a’ is the ASCII code for a beep. To emit a beep from your program, output this escape sequence to the standard output. For example: const char
C++ defines four possible forms for a class’s copy constructor. For a class called X, a copy constructor can have one of the following forms: X(X&);X(const X&);X(volatile X&);X(const volatile X&);
Technically speaking, constructors have no name. This may seem strange at first because you define a constructor for class X as X::X(). However, this construct is not the name of
A reader asked me the following questions: “Can a function that returns something, throw a exception and still return a value?” Lets’ look at a concrete example: int f(){ if
