What does the full-text database include?

Full-text database mainly includes electronic books, electronic magazines, electronic newspapers, etc. The full-text database eliminates the need for document indexing and other processing steps, and reduces human factors in data organization. Therefore, the data is updated quickly and the accuracy of search results is higher. At the same time, since the full text is directly provided, it saves the trouble of finding the original text. , so it is deeply loved by users.

The operating system for this tutorial: Windows 11 system, Dell G3 computer.

Full-text database is a database that contains the full text of original documents, mainly journal articles, conference papers, government publications, research reports, legal provisions and cases, business information, etc. The full-text database eliminates the processing steps such as document indexing and description, and reduces human factors in data organization. Therefore, the data is updated quickly and the accuracy of search results is higher. At the same time, because the full text is directly provided, it saves the trouble of finding the original text. , so it is deeply loved by users. The number of full-text databases has skyrocketed. Currently, the ratio of the number of full-text databases to bibliographic databases has reached about 2:1, and the number is still on the rise.

The structure definition of the database, the data content of the full-text database, the usage statistics and adjustment of vocabulary and storage space used in the full-text system.

Classification

According to the presentation form of information content in the full-text database, the main types of full-text database include electronic books, electronic magazines, electronic newspapers, etc.

The electronic version of books is generally published in parallel with the printed version, and has functions such as browsing, retrieval, sorting, printing, and copying. E-books can be accessed online, which improves the efficiency of document transmission and the availability of documents. The emergence of electronic books will improve (change) people's reading habits.

Electronic magazines can combine the retrieval of documents with the acquisition of original documents. The full-text database contains multiple journals, allowing full-text retrieval across disciplines and journals, expanding the scope of sources for obtaining information. The Chinese Academic Journals Network (http://WWW.cnki.net) is built by China Academic Journals (CD-ROM version)

electronic magazine and Tsinghua Tongfang CD-ROM Co., Ltd., and the Chinese journals full-text database includes There are more than 3,000 journals and more than 6 million documents.

Electronic newspapers store and manage newspaper articles and news reports through databases, and can be searched and queried online. The New York Times full-text database, Information Bank, was a pioneer of this type of database and was later incorporated into the NEXIS system at Mead Data Center. The CD-ROM version of the "People's Daily Full-text Database" jointly issued by China's "People's Daily" and Beijing Jinpan Electronics Co., Ltd., and the CD-ROM version of the "China Daily Full-text Database" jointly issued by the "China Daily" and China Science and Technology Data Import and Export Corporation, It is the first full-text database of news newspapers in China.

Structure

Full-text databases have various structural forms.

One structure is that the full-text database is composed of several libraries, each library is divided into several documents, the document is composed of several information carriers, and the information carrier is subdivided into several fragments. The fragments refer to the natural paragraphs that constitute the text. Equivalent to fields. LEXIS in the Mead data center in the United States has this structure. It is a menu-driven system. The first-level menu displays the library directory, and the second-level menu displays the document directory. After the library and document are selected, the system begins to receive questions.

Another structure is that the full-text database is composed of several databases. There is no document-level structure under the database, but the information carrier is directly divided into fields for storage. WESTLAW of Western Publishing Company of the United States has this structure. This system has court fields, judge fields, etc., and can provide a variety of search methods. The structure of the full-text database is similar to that of the bibliographic database. Its main document is a text file organized in a sequential format, and the inverted file is an index file corresponding to the searchable fields of the information carrier record. The tape format recorded in a full-text database is generally divided into several parts such as header, directory and data part. In existing full-text databases, different implementation methods are adopted according to the different situations of domain information carriers, database users and equipment.

Features

Compared with other databases, the full-text database has many features, the main performances are as follows.

① Contains the originality of the information. The information in the database is basically unprocessed original documents, so it is objective.

② Thoroughness of information retrieval. Any word, sentence, or character can be searched, and you may also see some marginal information.

③Retrieve the naturalness of language. Natural language retrieval can be used, and Boolean and location retrieval can be used, thus involving natural language understanding.

④The data structure is basically unstructured. Except for some standardizable data, a large amount of text is unstructured and is inconvenient for relational database processing.

⑤Professional full-text database systems generally use "automatic word segmentation" technology

⑥A good full-text database also has a knowledge base, which can have reasoning capabilities and associative retrieval.

⑦ It is basically closed, the data does not need to be updated, and it has greater stability.

⑧Full-text databases generally occupy a very large storage space and require large system overhead. How to improve the retrieval speed is a big problem.

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