FAQs

• How to programmatically find out when the SQL Server service started?

  Everytime SQL Server starts, it recreates the tempdb database. So, the creation date and time of the tempdb database tells us the date and time at which SQL Server service started. This information is stored in the crdate column of the sysd...

• Why are my insert, update statements failing with the following error?

  This error occurs, when the length of the value entered by you into a char, varchar, nchar, nvarchar column is longer than the maximum length of the column. For example, inserting 'FAQ' into a char(2) column would result in this error. P...

• Can one use dynamic SQL statements from PL/SQL?

  Starting from Oracle8i one can use the "EXECUTE IMMEDIATE" statement to execute dynamic SQL and PL/SQL statements (statements created at run-time).

• Can one call DDL statements from PL/SQL?

  One can call DDL statements like CREATE, DROP, TRUNCATE, etc. from PL/SQL by using the "EXECUTE IMMEDIATE" statement (native SQL).

• Can one read/write files from PL/SQL?

  The UTL_FILE database package can be used to read and write operating system files. A DBA user needs to grant you access to read from/ write to a specific directory before using this package.

• Can one print to the screen from PL/SQL?

  One can use the DBMS_OUTPUT package to write information to an output buffer. This buffer can be displayed on the screen from SQL*Plus if you issue the SET SERVEROUTPUT ON; command.

• How can I protect my PL/SQL source code?

  Oracle provides a binary wrapper utility that can be used to scramble PL/SQL source code. This utility was introduced in Oracle7.2 (PL/SQL V2.2) and is located in the ORACLE_HOME/bin directory. The utility use human-readable PL/SQL sourc...

• How can one search PL/SQL code for a string/ key value?

  SELECT type, name, line FROM user_source WHERE UPPER(text) LIKE UPPER('%&KEYWORD%');

• How can one see if somebody modified any code?

  The source code for stored procedures, functions and packages are stored in the Oracle Data Dictionary. One can detect code changes by looking at the TIMESTAMP and LAST_DDL_TIME column in the USER_OBJECTS dictionary view.

• Should one use PL/SQL or Java to code procedures and triggers?

  Both PL/SQL and Java can be used to create Oracle stored procedures and triggers. This often leads to questions like "Which of the two is the best?" and "Will Oracle ever desupport PL/SQL in favour of Java?". Many Oracle applications are...

• What is the difference between SQL and PL/SQL?

  Both SQL and PL/SQL are languages used to access data within Oracle databases. SQL is a limited language that allows you to directly interact with the database. You can write queries (SELECT), manipulate objects (DDL) and data (DML) with...

• What is PL/SQL and what is it used for?

  SQL is a declarative language that allows database programmers to write a SQL declaration and hand it to the database for execution. As such, SQL cannot be used to execute procedural code with conditional, iterative and sequential statement...

• Can I unit test Seam applications without starting the Application Server?

  Yes, Seam provides its own integration test framework based on TestNG. You can easily mock all Seam services using those facilities without ever loading an application server or a database. Refer to the testexample ANT target in the Seam bo...

• Can I use AJAX with Seam?

  Yes, Seam provides excellent support for AJAX. First, Seam supports the ICEfaces and Ajax4JSF Ajax component libraries for JSF. If you prefer a more "old fashioned" approach, Seam provides a complete JavaScript remoting framework which lets...

• Are there books about Seam?

  Yes, Prentice Hall's "JBoss Seam: Simplicity and Power Beyond Java EE 5.0" is a comprehensive guide for Seam written by JBoss insiders.

• Can I run Seam with JDK 1.4 and earlier?

  No, Seam only works on JDK 5.0 and above. It uses annotations and other JDK 5.0 features.

• Can I run Seam in a J2EE environment?

  Yes, as of Seam 1.1, you can use Seam in any J2EE application server, with one caveat: you will not be able to use EJB 3.0 session beans. However, you can use either Hibernate or JPA for persistence, and you can use Seam JavaBean components...

• Can I run Seam outside of JBoss AS?

  Yes, you can run Seam applications in plain Tomcat 5.5+ or in the Sun GlassFish application server. To run Seam application in Tomcat, you need a number of additional library files and a few configuration files to bootstrap the JBoss EJB3 i...

• What version of JBoss AS do I need to run Seam?

  For Seam 1.3: Seam was developed against JBoss 4.2. Seam can still be run against JBoss 4.0. The seam documentation contains instructions for configuring JBoss 4.0.

• What is the K virtual machine (KVM)?

  K virtual machine (KVM) is a Java virtual machine that provides the basis for the CLDC reference implementation (RI). K stands for "Kilobyte" virtual machine, referring to the small footprint of the platform. The K virtual machine is very s...

• How do I ship products based on CLDC?

  In order to ship products based on CLDC, the CLDC implementation must pass the Technology Compability Kit (TCK) provided by Sun. For more information about TCK commercial licensing terms, please contact your local Sun sales representative.

• Is a virtual machine all that's needed to run a small application?

  No. A virtual machine requires a set of core libraries to run applications. Some of these libraries are packaged as a part of a CLDC implementation along with the virtual machine. In addition, the capabilities of CLDC can be extended by add...

• Is CLDC a virtual machine?

  No. CLDC specifies the core libraries and virtual machine features for J2ME implementations on resource-constrained devices. A CLDC implementation includes a virtual machine. For instance, KVM is included in the CLDC reference implementatio...

• What kinds of products is J2ME CLDC suited for?

  The CLDC configuration was designed to bring the many advantages of the Java platform to connected devices that are limited in available resources. Targeted devices include cellular phones, pagers, mobile point-of-sale terminals, and any ot...

• How are configurations and profiles defined?

  Configurations, profiles and optional packages are defined by open industry working groups utilizing the Java Community Process program. In this way industries can decide for themselves what elements are necessary to provide a complete solu...

• What are optional packages?

  The J2ME platform can be further extended by combining various optional packages with configurations and their corresponding profiles. Created to address very specific market requirements, optional packages offer standard APIs for using bot...

• What is a profile?

  In order to provide a complete runtime environment targeted at specific device categories, configurations must be combined with a set of higher level APIs, or profiles, that further define the application life cycle model, the user interfac...

• What is the Connected Limited Device Configuration (CLDC)?

  The CLDC specification was developed within the Java Community Process[sm] (JCP[sm]) program in collaboration with over 500 partners representing the wireless handset, service provider, and point of sale terminal industries. It outlines the...

• What is the Java 2 Platform, Micro Edition (J2ME technology)?

  The J2ME platform is targeted at consumer electronics and embedded devices. It is comprised of a set of configurations, profiles, and standard extensions that can be used to build complete Java runtime environments that meet the requirement...

• What Eclipse newsgroups are available?

  As with most technologies, Eclipse started out with a single newsgroup. Now, all major, and some smaller, Eclipse projects have their own newsgroups. Some are more active than others. Some have a very specific scope, and others are more bro...

• Who uses Eclipse in the classroom?

  A growing number of universities worldwide are deploying Eclipse as a vehicle for computer science classes. The platform itself can be used very well as an example of state-of-the-art software. Analysis of the Design Patterns adopted in Ecl...

• What academic research projects are based on Eclipse?

  Much of the academic research on Eclipse is propelled by the Eclipse Innovation Grants, a financial stimulation project funded by IBM in 2003 and renewed for 2004. The award winners are prominently profiled at the Eclipse community Web site...

• What open source projects are based on Eclipse?

  Thousands of projects of various sizes are based on Eclipse. A small number are directly supported by the Eclipse Foundation as official Eclipse projects but a far greater number can be found elsewhere on the Web. Many are hosted at such si...

• Who is building commercial products based on Eclipse?

  Each member of the Eclipse Foundation has committed to delivering one or more products based on Eclipse. For example, IBM has moved almost all of its IDE products to the Eclipse Platform. At EclipseCon 2004, many companies showed exciting d...

• What are Eclipse projects and technologies?

  The three outputs of this project are the Eclipse Platform, Java development tools (JDT) and Plug-in Development Environment (PDE) tools. These three components comprise the Eclipse SDK, a full-featured Java IDE with all the necessary featu...

• How can my users tell where Eclipse ends and a product starts?

  You cannot see where Eclipse ends and a product starts, and this is intentional. The platform itself is written entirely as a set of plug-ins, and the product plug-ins simply join the “soup of swimming plug-ins.” To bring some order to the...

• Where did Eclipse come from?

  Eclipse started out as proprietary technology, led by IBM’s subsidiary, Object Technology International (OTI). IBM wanted to reduce the large number of incompatible development environments being offered to its customers and to increase the...

• What is the Eclipse Platform?

  Those who download the generic Eclipse Platform—usually by mistake—are somewhat confounded by what they see. The platform was conceived as the generic foundation for an IDE. That is, the platform is an IDE without any particular programming...

• What is Eclipse?

  Eclipse means a lot of different things to different people. To some Eclipse is a free, state-of-the-art Java development environment. To others, Eclipse is a flexible environment to experiment with new computer languages or extensions to e...

• How can I disable the "No symbols found" messages that show on the debug output window when I debug my program?

  Unfortunately, you can't configure most of what shows on the debug output window, including the dll load messages. This, however, is not an error message. It simply informs you that the IDE found no debug symbols for the loaded DLL. One...

• What does Link warning LNK4089 mean, and how can I avoid it?

  This warning simply means that you are linking against a library and the linker has detected that you are not really using any functions from it. This warning usually only pops when you are making release builds, because the /OPT:REF switch...

• Does VisualC++ take advantage of my SMP machine to compile faster?

  In short: no. The Microsoft C/C++ compiler is not optimized for multiprocessor machines, nor does DevStudio or NMAKE take advantage of them by performing parallel builds. Also, the compiler itself is not [currently] multithreaded, as the co...

• Why do I get an "Can't access sample data" on VC++ 5 when I try to copy the sample projects?

  The reason for this is an incompatibility with Internet Explorer 4 (IE4). The update that fixes this problem can be obtained by installing the Visual Studio Service Pack 3 (SP3), which you can download from Microsoft's Visual C++ page.

• How can I copy a dialog resource from one project to another?

  You can copy the resource directly. Open the .rc files from both projects in VC++ as text files, or open them in your favorite text editor, and copy the relevant bits from one to another. You can spot the portion of the file you need to cop...

• How can I delete a class from my project?

  It's not as easy as it seems. Unfortunately, the Class Viewer doesn't directly support this option, so you have to a lot of work. First, you have to start by removing the .h and .cpp files that implement the class itself. You do this by swi...

• I have a combo box in my dialog, but it won't drop down, why?

  You need to set the height of the dropdown. You can do this in the dialog editor. Open your dialog template, then click on the combo box to select it. Now click on the down arrow on the right and you should be able to resize the combo bo...

• How do I get Visual Studio to recognize .cc files as c++ source files?

  Use the /Tp option of the compiler to instruct it to assume the file is C++. You can put this in as a custom build rule, or modify some registry settings to add .cc to the list of file extensions recognized as C++. The key to modify is:...

• What are the different types of software testing that can be considered?

  White box testing, Unit testing, Functional testing, Black box testing, System testing, Acceptance testing, End-to-end testing, Integration testing, Mutation testing, Compatibility testi...

• What is ‘good design’ in software programs?

  ‘Design’ in a software program could mean either ‘internal design’ or ‘functional design’. If the overall structure of the software program can be easily modified, understood and maintained, then it can be said that the software program has...

• What is 'good code'?

  Good code is code that has no bugs, works well, is easily readable and can be maintained with ease. Developers and testers usually follow varied theories, metrics and standards to ensure good code. With the help of pair programming, reviews...