File Management - IBM
File Management - IBM File Management - IBM
2 File Management V4R5 v Distributed data management (DDM) files are files that allow access to data files stored on remote systems. Each file type has its own set of unique characteristics that determines how the file can be used and what capabilities it can provide. The concept of a file, however, is the same regardless of what type of file it is. When a file is used by a program, it is referred to by name, which identifies both the file description and, for some file types, the data itself. This information is designed to help you understand the common characteristics of all file types so you can use the files to their full capabilities. Related tasks: See the following links for information on the tasks you can perform against files: v Copy files v Open files v Secure files v Share files v Temporarily override the properties of a file
Chapter 2. File processing This chapter discusses basic aspects of processing files. Topics include: v File operations supported by the system for use in high-level language programs v File security considerations v Sharing files in the same job v Allocating file resources v Temporarily changing a file when a program uses it v Feedback areas maintained by the system v Handling file errors when programs run File Management operations overview File management supports many operations that high-level language programs can use to process data. These include the following, which are grouped by category: v File Preparation OPEN Attaches a file to a program and prepares it for I/O operations. A file may be opened for any combination of read, write, update, or delete operations. ACQUIRE Attaches a device or establishes a communications session for an open file in preparation for I/O operations. v Input/Output READ Transfers a record from the file to the program. The data is made available to the program once the read has been successfully completed. WRITE Transfers a record from the program to the file. WRITE-READ Combines the WRITE and READ operations as one operation. UPDATE Updates a record with changed data. The record must have been successfully read prior to the update operation. DELETE Deletes a record in a file. The record must have been successfully read prior to the delete operation. v Commitment Control COMMIT Guarantees a group of changes are made as a complete transaction across multiple records or multiple files. ROLLBACK Rolls back a group of changes to the point of the last commit operation. v Completion FEOD Positions the file at the last volume or at the end of data. For those © Copyright IBM Corp. 1998, 2000 3
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2 <strong>File</strong> <strong>Management</strong> V4R5<br />
v Distributed data management (DDM) files are files that allow access to data<br />
files stored on remote systems.<br />
Each file type has its own set of unique characteristics that determines how the file<br />
can be used and what capabilities it can provide. The concept of a file, however, is<br />
the same regardless of what type of file it is. When a file is used by a program, it<br />
is referred to by name, which identifies both the file description and, for some file<br />
types, the data itself. This information is designed to help you understand the<br />
common characteristics of all file types so you can use the files to their full<br />
capabilities.<br />
Related tasks:<br />
See the following links for information on the tasks you can perform against files:<br />
v Copy files<br />
v Open files<br />
v Secure files<br />
v Share files<br />
v Temporarily override the properties of a file
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