The file control commands can access shared data tables. Shared data tables offer a method of constructing, maintaining, and gaining rapid access to data records contained in tables held in virtual storage, above the 16MB line. Each shared data table is associated with a VSAM KSDS, known as its source data set. For more information about shared data tables, see the CICS® Shared Data Tables Guide.
A table is defined using the CEDA DEFINE FILE panel. When a table is opened, CICS builds it by extracting data from the table’s corresponding source data set and loading it into virtual storage above the 16MB line.
CICS supports two types of shared data table, as follows:
Note that the source for a CICS-maintained data table cannot be a file opened in RLS access mode.
The full file control API appropriate to VSAM KSDS data sets is supported for CICS-maintained data tables. Requests that cannot be satisfied by reference to the data table result in calls to VSAM to access the source data set. Tables defined to be recoverable are supported with full integrity.
A subset of the file control API is supported for user-maintained tables. For programming information about the commands, you should see the CICS Application Programming Reference manual where they are listed separately under the file control command name, followed by UMT. For example, the information on writing a record to a user-maintained table is given under WRITE(UMT). A table defined as recoverable participates in dynamic transaction backout but is not recovered at restart or XRF takeover.
[[ Contents Previous Page | Next Page Index ]]