if we use the cursor we can fetch the dupliacte records from the table.
2)The VSAM data base is of file concept and the datadase may be table concept,etc
Th data base can store more records into it and the access from the DB is very fast....
The vsam is a file concept while u could say the database is a collection of vsam files .obviously databases are more preferable and agin that depends on the volume of data being processed.
but vsam are more cost effective so it is up to the requirement to decide
restart logic is a concept used in IMS where we treat all the files(i/p and o/p) as GSAM DATABASES so that we could take checkpoints easily.
IMS Checkpoint gives us the ability to take a program image and retain its valuable contents which is in working storage so that you can recompile and restart your program execution without loosing any information in case of job abends.The checkpoint
1. Allows restart possibility from the Last commit point.
2. Ensure database /File integrity
3. Records checkpoint data on IMS Log files.
so when a job abends we do not lose any info and we can restart from the last checkpoint.