Oracle Connect supports two types of VSAM data sources:

  • VSAM (CICS): The VSAM under CICS data source accesses VSAM by making EXCI calls to a CICS program provided as part of the Oracle Connect installation. This agent CICS program does the actual VSAM reads and writes from within CICS. When accessing VSAM data using this data source, the following restrictions apply:
    • SQL DELETE operations are not supported for ESDS files.
    • Using an alternate index to access an ESDS file is not supported.
    • A non-unique alternate index for a KSDS file is not supported.
  • VSAM: This data source connects directly to the VSAM data and is limited if the VSAM files are managed by CICS. In this case, it is recommended to use this data source for read-only access to VSAM files. However, this may not give you adequate read integrity if some changes are buffered by CICS. Another alternative is to use the VSAM under CICS data source. When accessing VSAM data using the VSAM data source, the following restrictions apply:
    • Transactions are not supported when accessing VSAM directly.
    • When accessing VSAM under CICS, global transactions are supported.
    • Locking is not supported.
    • You cannot update an array value (a child record in a hierarchical table) when the parent record is included in the SQL in a subquery.
    • SQL DELETE operations are not supported for ESDS files.
    • An RRDS file cannot have an alternate index.
    • The primary key of a KSDS file must be one segment only (however, it can be several consecutive fields). You cannot modify the primary key value of a KSDS file.
    • To enable you to create and delete VSAM data under OS/390 and z/OS, submit the following JCL:
      // IDCSYSIN DD DSN=&&VSAM,DISP=(NEW,DELETE,DELETE),
      // SPACE=(TRK,(1)),UNIT=SYSDA,
      // DCB=(BLKSIZE=3200,LRECL=80,RECFM=FB)