File Types and Processing Methods

Table 1 shows the valid entries for positions 28, 34, and 35 of the file description specifications for the various file types and processing methods. The methods of disk file processing include:

Relative-record-number processing
Consecutive processing
Sequential-by-key processing
Random-by-key processing
Sequential-within-limits processing.

Table 1. Processing Methods for DISK Files
Access	Method	Opcode	Position 28	Position 34	Position 35	Explanation
Random	RRN	CHAIN	Blank	Blank	Blank	Access by physical order of records
Random	RRN	CHAIN	Free-form syntax: (No keyword is necessary)			Access by physical order of records
Sequential	Key	READ READE READP READPE cycle	Blank	Blank	I	Access by key sequentially
Sequential	Key	READ READE READP READPE cycle	Free-form syntax: KEYED keyword			Access by key sequentially
Sequential	Within Limits	READ READE READP READPE cycle	L	A, P, G, D, T, Z, or F	I	Access by key sequentially controlled by record- address-limits file
Sequential	Within Limits	READ READE READP READPE cycle	Free-form syntax: (Not supported for a free-form file definition)
Sequential	RRN	READ cycle	Blank	Blank	T	Access sequentially restricted to RRN numbers in record-address file
Sequential	RRN	READ cycle	Free-form syntax: (Not supported for a free-form file definition)

For further information on the various file processing methods, see the section entitled "Methods for Processing Disk Files", in the chapter "Accessing Database Files" in the Rational Development Studio for i: ILE RPG Programmer's Guide.