| 单词 | data dictionary |
| 释义 | data dictionarydata dictionarydata dictionarydata dictionary[′dad·ə ‚dik·shə‚ner·ē]data dictionary(database)Most generally it is a set of data descriptions thatcan be shared by several applications. Usually it means a table in a database that stores thenames, field types, length, and other characteristics ofthe fields in the database tables. An active data dictionary is automatically updated as changesoccur in the database. A passive data dictionary must bemanually updated. In a DBMS, this functionality is performed by the system catalog. The data dictionary is a more general softwareutility used by designers, users, and administrators forinformation resource management. The data dictionary may maintain information on systemhardware, software, documentation, users, and other aspects. Data dictionaries are also used to document the databasedesign process itself and can accumulate meta-dataready to feed into the system catalog. data dictionaryA database about data and databases. A data dictionary holds the name, type, range of values, source and authorization for access for each data element in the organization's files and databases. It also indicates which application programs use that data so that when a change in a data structure is contemplated, a list of affected programs can be generated.The data dictionary may be a stand-alone system or an integral part of the DBMS. Data integrity and accuracy is better ensured in the latter case. See DBMS and data administration. data dictionaryda·ta dic·tion·a·ry(dā'tă dik'shŭn-ār-ē)See DDIC |
| 随便看 |
英语词典包含2567994条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。