Tham khảo tài liệu 'giáo trình hình thành ứng dụng phân tích cấu tạo và công dụng của máy in theo setup catridge p3', công nghệ thông tin, kỹ thuật lập trình phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | a. The records in logical file are brought into some sequence as determined by key in the records. b. A computer is capable of sorting record into a nested sequence. c. Sorting is done by a sorting generator . This is part of the computer s software and comprises several sophisticated sorting techniques that are called into use according to the file and the sort requirements. d. The need of sorting has dimished in line with the demise of magnetic tape as backing storage. 2. Merging - Merging implies that two or more files in the same sequence are combined into one file. a. File merging Two or more separate files of similar seconds and in the same sequence are marged together so as to form one file. b. Record merging The records from two or more input files usually in the same sequence are combined one record in the output file. 3. Matching a. Two or more input files generally in the same sequence are compared records against record in order to ensure that there is a complete set of records for each key. b. Masmatched records are highlighted for subsequent action 4. Summanizing a. Records with the same key in one file are accumulated together to form one record in the output file. b. Summanizing usually applies to a file presorted into a certain sequence and the resultant file is in the same sequence. c. Records to be summarized are generally of a similar type. 5. Searching a. Searching is looking for records with certain keys or holding certain data and in some way making a note of these. b. An instance is a search for and count of all records with a debt balance of above a certain amount. 6. Information retrieval a. Information retrieval is the process that involves the bringing together of data from several files. b. Data may also be extracted from several files and combined before being presented as information. Chapter 8 DIRECT ACCESS FILE ORGANIZATION AND STRUCTURES. Question 1. Storage and Access Modes There are 3 principal modes for storing and accessing .
