Question

Difference between sequential and indexed sequential in sad

Answer 1

That is the difference between sequential and direct access organization for database records. Sequential file organization , in conjunction with magnetic tape, is typically used for processing the same information on all records at the same time. ... Direct or random file organization is used with magnetic disks.

Answer 2

Sequential files are called as QSAM files. Indexed files are also called as VSAM files. Relative called as VSAM files (RRDS).
Data is entered in entry sequential order. Data is entered in key sequential order. Data is entered in RRN number.
Duplicate data is allowed. Duplicate data is not
allowed. Duplicate data is not allowed
Data is not in sorted order. Data is in sorted order based on key. Date is in sorted order based on RRN.
Delete is not applicable. Delete is applicable. Delete is applicable.
Access is slow. Access is faster. Access is faster than indexed files.
Key is not available. Key is available. Key is user defined. Key is part of a record. Key is available. Key is system defined, key is outside of a record.
Data is stored on tape/disk. Data is stored on disk only. Data is stored on disk only.
File modes. INPUT. OUTPUT. I-O. EXTEND. File modes. INPUT. OUTPUT. I-O. File Modes. INPUT OUTPUT I-O
Frequently used files. Rarely used files. Not yet all used.
Thanq
Hope it helps.