background preloader

Database

Database
Database management systems (DBMSs) are specially designed software applications that interact with the user, other applications, and the database itself to capture and analyze data. A general-purpose DBMS is a software system designed to allow the definition, creation, querying, update, and administration of databases. Well-known DBMSs include MySQL, MariaDB, PostgreSQL, SQLite, Microsoft SQL Server, Oracle, SAP HANA, dBASE, FoxPro, IBM DB2, LibreOffice Base and FileMaker Pro. Terminology and overview[edit] Formally, "database" refers to the data themselves and supporting data structures. A "database management system" (DBMS) is a suite of computer software providing the interface between users and a database or databases. Outside the world of professional information technology, the term database is sometimes used casually to refer to any collection of data (perhaps a spreadsheet, maybe even a card index). The interactions catered for by most existing DBMSs fall into four main groups: Related:  WikiBIRD

Product (business) In marketing, a product is anything that can be offered to a market that might satisfy a want or need.[1] In retailing, products are called merchandise. In manufacturing, products are bought as raw materials and sold as finished goods. Commodities are usually raw materials such as metals and agricultural products, but a commodity can also be anything widely available in the open market. In project management, products are the formal definition of the project deliverables that make up or contribute to delivering the objectives of the project. In insurance, the policies are considered products offered for sale by the insurance company that created the contract. Dangerous products, particularly physical ones, that cause injuries to consumers or bystanders may be subject to product liability. A product can be classified as tangible or intangible. A third type in this is services. Various classification systems for products have been developed for economic statistical purposes.

SpiderMonkey (JavaScript engine) SpiderMonkey is the code name for the first-ever JavaScript engine, written by Brendan Eich at Netscape Communications, later released as open source and now maintained by the Mozilla Foundation. SpiderMonkey currently provides JavaScript support for Mozilla Firefox and various embeddings such as the GNOME 3 desktop. TraceMonkey was the first JIT compiler written for the JavaScript language. Instead of compiling whole functions, TraceMonkey was a tracing JIT a operates by recording control flow and data types during interpreter execution. Improvements to JägerMonkey eventually made TraceMonkey obsolete, especially with the development of the SpiderMonkey type inference engine. JägerMonkey, internally named MethodJIT, was a whole-method JIT compiler designed to improve performance in cases where TraceMonkey could not generate stable native code.[8][9] It was first released in Firefox 4 and eventually entirely supplanted TraceMonkey.

Data (computing) Data (/ˈdeɪtə/ DAY-tə, /ˈdætə/ DA-tə, or /ˈdɑːtə/ DAH-tə;[1] treated as singular, plural, or as a mass noun) is any sequence of one (1) or more symbols given meaning by specific act(s) of interpretation. Data is not information. Data requires interpretation to become information. To translate data to information, there must be several known factors considered. The factors involved are determined by the creator of the data and the desired information. Digital data is data that is represented using the binary number system of ones (1) and zeros (0). In an alternate usage, binary files (which are not human-readable) are sometimes called "data" as distinguished from human-readable "text".[4] The total amount of digital data in 2007 was estimated to be 281 billion gigabytes (= 281 exabytes).[5][6] At its most essential, a single datum is a value stored at a specific location. To store data bytes in a file, they have to be serialized in a "file format".

What is Database (DB)? Webopedia Main » TERM » D » By Vangie Beal (1) Often abbreviated DB, a database is basically a collection of information organized in such a way that a computer program can quickly select desired pieces of data. Traditional databases are organized by fields, records, and files. An alternative concept in database design is known as Hypertext. To access information from a database, you need a database management system (DBMS). (2) Increasingly, the term database is used as shorthand for database management system. Adobe Flash Flash manipulates vector and raster graphics to provide animation of text, drawings, and still images. It allows bidirectional streaming of audio and video, and it can capture user input via mouse, keyboard, microphone and camera. Flash applications and animations can be programmed using the object-oriented language called ActionScript. Adobe Flash Professional is the most popular and user-friendly authoring tool for creating the Flash content, which also allows automation via the JavaScript Flash language (JSFL). History[edit] Open Screen Project[edit] As of February 2009[update], the specifications removing the restrictions on the use of SWF and FLV/F4V specs have been published.[6] The Flash Cast protocol—now known as the Mobile Content Delivery Protocol—and AMF protocols have also been made available,[6] with AMF available as an open source implementation, BlazeDS. As of 2012[update], the Open Screen Project is no longer accepting new applications according to partner BSQuare.

Message Passing Interface History[edit] The message passing interface effort began in the summer of 1991 when a small group of researchers started discussions at a mountain retreat in Austria. Out of that discussion came a Workshop on Standards for Message Passing in a Distributed Memory Environment held on April 29–30, 1992 in Williamsburg, Virginia. At this workshop the basic features essential to a standard message-passing interface were discussed, and a working group established to continue the standardization process. Jack Dongarra, Rolf Hempel, Tony Hey, and David W. The MPI effort involved about 80 people from 40 organizations, mainly in the United States and Europe. The MPI standard defines the syntax and semantics of a core of library routines useful to a wide range of users writing portable message passing programs in Fortran and C. MPI provides parallel hardware vendors with a clearly defined base set of routines that can be efficiently implemented. Overview[edit] Functionality[edit] Concepts[edit]

Database tuning Database tuning describes a group of activities used to optimize and homogenize the performance of a database. It usually overlaps with query tuning, but refers to design of the database files, selection of the database management system (DBMS) application, and configuration of the database's environment (operating system, CPU, etc.). Database tuning aims to maximize use of system resources to perform work as efficiently and rapidly as possible. I/O tuning[edit] Hardware and software configuration of disk subsystems are examined: RAID levels and configuration,[1] block and stripe size allocation, and the configuration of disks, controller cards, storage cabinets, and external storage systems such as SANs. DBMS tuning[edit] DBMS tuning refers to tuning of the DBMS and the configuration of the memory and processing resources of the computer running the DBMS. Memory is allocated for data, execution plans, procedure cache, and work space[clarify]. Database maintenance[edit] References[edit]

AJAX (תכנות) AJAX, ראשי תיבות של Asynchronous JavaScript And XML, היא טכניקה ליצירת יישומי דפדפן אינטראקטיביים המבוססים על קוד המורץ במסגרת דף HTML בודד, ולא כיישום מרובה דפים, כמקובל בסביבת הווב. מטרתה העיקרית של הטכניקה היא שיפור חוויית המשתמש והאצת מהירות הטעינה של דפי האינטרנט, מאחר שהיא מאפשרת לעדכן רק חלקים מבוקשים בדף האינטרנט, ללא צורך לטעון את הדף כולו מחדש במחשבו של המשתמש. מטרה זו מושגת באמצעות יצירת תקשורת והחלפת מידע בין מחשב הלקוח לשרת דפי האינטרנט באמצעות קוד JavaScript. כלומר, האינטראקטיביות של יישומי AJAX מושגת באמצעות קוד המורץ בצד-הלקוח, זאת בניגוד לשימוש טהור בטכנולוגיות כמו PHP ו-ASP, שבהן הקוד מורץ בצד-השרת, וללקוח מגיע דף HTML סטטי, ולא יישום מלא. כאשר משתמשים ב-AJAX עדיין יש צורך בטכנולוגיית צד-שרת כמו PHP או ASP, אלא שבמקום לשלוח דף HTML שלם, נשלח ללקוח רק המידע, והלקוח מפרש את המידע ומציג אותו למשתמש. טכניקת AJAX משתמשת בשילוב של טכנולוגיות קיימות: יתרונות השיטה: חסרונות השיטה:

Computer cluster A computer cluster consists of a set of loosely or tightly connected computers that work together so that, in many respects, they can be viewed as a single system. Unlike grid computers, computer clusters have each node set to perform the same task, controlled and scheduled by software.[1][better source needed] The components of a cluster are usually connected to each other through fast local area networks ("LAN"), with each node (computer used as a server) running its own instance of an operating system. In most circumstances, all of the nodes use the same hardware[2] and the same operating system, although in some setups (i.e. using Open Source Cluster Application Resources (OSCAR)), different operating systems can be used on each computer, and/or different hardware.[3] They are usually deployed to improve performance and availability over that of a single computer, while typically being much more cost-effective than single computers of comparable speed or availability.[4] History[edit]

Critère de succès : la taille de l'équipe Il y a eu de nombreuses études sur la performance des équipes en fonction de leur taille. La conclusion générale est que la taille optimale d'une équipe se situe à peu près entre sept et onze personnes. Il s'agit d'un juste équilibre, entre d'une part une équipe avec trop peu de personnes pour assurer la diversité et l'expertise et, d'autre part trop de personnes pour obtenir une pleine participation et une communication ouverte.Lorsque les équipes deviennent trop grandes, il leur est très difficile de parvenir à une compréhension commune d'un problème ou d'une situation. Le niveau de performance d'une équipe est très sensible aux relations individuelles entre les membres de l'équipe.

Related: