關(guān)于計算機(jī)講數(shù)據(jù)庫概況的英語
計算機(jī)是我們我們可以多多學(xué)習(xí)的英語，所以小編今天就給大家整理了有關(guān)于計算機(jī)的英語，有時間可以參考一下
計算機(jī)英語
facilitate 使容易，促進(jìn)
retrieval n. 檢索
field n. 字段
record 記錄，
alphabetically 按字母順序地
chronologically 按年代順序排
break down v. 分解
build up 建造，裝配，組成
encyclopedia n. 百科全書
reference n. 涉及，參考，引用
bibliography 書目，參考書目
periodical n. 期刊，雜志
literature n. 文獻(xiàn)，著作
professional n. 專業(yè)人員，專家
A database consists of a file or a set of files. The information in these files may be broken down into records, each of which consists of one or more fields. Fields are the basic units of data storage, and each field typically contains information pertaining to one aspect or attribute of the entity described by the database. Using keywords and various sorting commands, users can rapidly search, rearrange, group, and select the fields in many records to retrieve or create reports on particular aggregates of data.
一個數(shù)據(jù)庫由一個文件或文件集合組成。這些文件中的信息可分解成一個個記錄，每個記錄有一個或多個域。域是數(shù)據(jù)存儲的基本單位，每個域一般含有由數(shù)據(jù)庫描述的屬于實體的一個方面或一個特性的信息。用戶使用鍵盤和各種排序命令，能夠快速查找、重排、分組并在查找的許多記錄中選擇相應(yīng)的域，建立特定集上的報表。
Database records and files must be organized to allow retrieval of the information. Early systems were arranged sequentially (i.e., alphabetically, numerically, or chronologically); the development of direct-access storage devices made possible random access to data via indexes. Queries are the main way users retrieve database information. Typically, the user provides a string of characters, and the computer searches the database for a corresponding sequence and provides the source materials in which those characters appear. A user can request, for example, all records in which the content of the field for a person's last name is the word Smith.
數(shù)據(jù)庫記錄和文件的組織必須確保能對信息進(jìn)行檢索。早期的系統(tǒng)是順序組織的(如：字母順序、數(shù)字順序或時間順序);直接訪問存儲設(shè)備的研制成功使得通過索引隨機(jī)訪問數(shù)據(jù)成為可能。用戶檢索數(shù)據(jù)庫信息的主要方法是query(查詢)。通常情況下，用戶提供一個字符串，計算機(jī)在數(shù)據(jù)庫中尋找相應(yīng)的字符序列，并且給出字符串在何處出現(xiàn)。比如，用戶能夠在所有記錄中尋找所有l(wèi)ast name域為Smith的記錄。
In flat databases [2], records are organized according to a simple list of entities; many simple databases for personal computers are flat in structure. The records in hierarchical databases are organized in a treelike structure, with each level of records branching off into a set of smaller categories. Unlike hierarchical databases, which provide single links between sets of records at different levels, network databases create multiple linkages between sets by placing links, or pointers, to one set of records in another; the speed and versatility of network databases have led to their wide use in business.
在非結(jié)構(gòu)化的數(shù)據(jù)庫中，按照實體的一個簡單列表組織記錄;很多個人計算機(jī)的簡易數(shù)據(jù)庫是非結(jié)構(gòu)的。層次型數(shù)據(jù)庫按樹型組織記錄，每一層的記錄分解成更小的屬性集。層次型數(shù)據(jù)庫在不同層的記錄集之間提供一個單一鏈接，與此不同，網(wǎng)絡(luò)型數(shù)據(jù)庫在不同記錄集之間提供多個鏈接，這是通過設(shè)置指向其它記錄集的鏈或指針來實現(xiàn)的。網(wǎng)絡(luò)型數(shù)據(jù)庫的速度及多樣性使其在企業(yè)中得到廣泛應(yīng)用。
Relational databases are used where associations among files or records cannot be expressed by links; a simple flat list becomes one table, or “relation”, and multiple relations can be mathematically associated to yield desired information. Object-oriented databases store and manipulate more complex data structures, called “objects”, which are organized into hierarchical classes that may inherit properties from classes higher in the chain; this database structure is the most flexible and adaptable.
當(dāng)文件或記錄間的關(guān)系不能用鏈表達(dá)時，使用關(guān)系型數(shù)據(jù)庫。一個表或一個“關(guān)系”，就是一個簡單的非結(jié)構(gòu)列表。多個關(guān)系可通過數(shù)學(xué)關(guān)系提供所需信息。面向?qū)ο蟮臄?shù)據(jù)庫存儲并處理更復(fù)雜的稱為對象的數(shù)據(jù)結(jié)構(gòu)，可組織成有層次的類，其中的每個類可以繼承層次鏈中更高一級類的特性，這種數(shù)據(jù)庫結(jié)構(gòu)最靈活，最具適應(yīng)性。
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