Reading a Data Item: Summary

This topic summarizes ways to read a data item or create a directory entry for a data item if one does not exist using IXLCACHE REQUEST=READ_DATA:

To identify the data item, code the NAME keyword.
To indicate that a directory entry for the data item is to be created if it does not already exist, code ASSIGN=YES. Directory-only users of the cache can specify this keyword.
To read an existing data item in the cache to the local cache buffer, code ASSIGN=NO. If the data item does not exist, the system fails the request. Store-in or store-through cache users can specify this keyword.
To read an existing data item, identify your local cache buffers by coding either BUFFER, or BUFLIST and their related keywords. The system transfers the data item from the data entry to your local cache buffers. If the data entry is empty (that is, data does not exist for the data item in the cache structure), the system does not transfer data to your local cache buffers, but registers interest for the data item in the directory entry.
If the cache structure supports adjunct data, use the ADJAREA keyword to read adjunct data. The system transfers the adjunct data from the cache structure to the buffer specified on the ADJAREA keyword.

You must assign a vector index entry by coding the VECTORINDEX keyword. If you assign a vector index entry that is currently associated with another data item, specify the name of that data item on the OLDNAME keyword. The system creates an association between the new data item and the vector index entry and registers your interest in the data item. If you also specified the OLDNAME keyword, the system deregisters your interest in the data item specified on OLDNAME.

For More Information

There are other keywords that are required and some that are optional. Some of these keywords apply to all IXLCACHE requests and others apply to just READ_DATA requests. For a description of keywords applicable to all IXLCACHE requests, see: