Главная страница Случайная страница КАТЕГОРИИ: АвтомобилиАстрономияБиологияГеографияДом и садДругие языкиДругоеИнформатикаИсторияКультураЛитератураЛогикаМатематикаМедицинаМеталлургияМеханикаОбразованиеОхрана трудаПедагогикаПолитикаПравоПсихологияРелигияРиторикаСоциологияСпортСтроительствоТехнологияТуризмФизикаФилософияФинансыХимияЧерчениеЭкологияЭкономикаЭлектроника |
Relational Database Systems
Following a famous paper written by Ted Codd in 1970, (1)… systems changed significantly. Codd proposed that database systems should present the user with a view of data organized as (2)… called relations. Behind the scenes, there might be a complex data (3)… that allowed (4)… response to a variety of (5)... But, unlike the user of earlier database systems, the (6)… of a relational system would not be concerned with the storage structure. Queries could be expressed in a very (7)… language, which greatly increased the (8)… of database programmers. Tables, database, user, rapid, high-level, structure, queries, efficiency IV. Change the words in brackets from Ukrainian into English. Databases today are (необхідний, дуже важливий або цінний) to every business. They are used to (зберігати) internal records, to (представляти або подавати на розгляд) data to customers and clients on the World-Wide-Web, and to (підтримувати) many other commercial processes. Databases are likewise found at the core of many scientific investigations. They represent the data gathered by astronomers, by investigators of the human genome, and by biochemists exploring the medicinal properties of proteins, along with many other scientists. The power of databases comes from a body of knowledge and technology that has developed over several decades and is embodied in specialized software called a (система управління базами даних або СУБД) or more colloquially a «database system». A DBMS is a powerful tool for creating and managing large amounts of data efficiently and allowing it to (залишатися або зберігатися) over long periods of time, safely. These systems are among the most complex types of software available. The (можливості) that a DBMS provides the user are: 1. (Постійне зберігання). Like a file system, a DBMS supports the storage of very large amounts of data that exists independently of any processes that are using the data. However, the DBMS goes far beyond the file system m providing flexibility, such as data structures that support efficient access to very large amounts of data. 2. Programming interface. A DBMS allows the user or an application program to (отримувати доступ) and (видозмінювати) data through a powerful query language. Again, the advantage of a DBMS over a file system is the (гнучкість) to manipulate stored data in much more complex ways than the reading and writing of files. 3. Transaction management. A DBMS supports (одночасний доступ) to data, i.e., simultaneous access by many distinct processes (called «transactions») at once. To avoid some of the (небажані наслідки) of simultaneous access, the DBMS supports isolation, the appearance that transactions execute one at-a-time, and atomicity, the requirement that transactions execute either completely or not at all. A DBMS also supports (стійкість), the ability to recover from failures or errors of many types.
|