Filter
Top Products
Record Addressing by KEY
Supply the key as follows:
Keyaddress points to a field containing the key of the record for which you are
searching. Blockaddress points to a field containing sufficient information to
identify the track on which the search is to begin.
Reference Methods
The following paragraphs describe record reference by ID and record reference
by key. In each method, relative track addressing and actual physical addressing
are applicable to VSE and MVS; relative block addressing is applicable only to
MVS. The relative block addressing technique locates a block by its position
relative to the first block of the data set.
Record Reference by ID
Under VSE, records can be referenced by ID when you specify READID and/or
WRITEID in the DTFDA. You must also supply both the track information and the
record number in the field specified by SEEKADDR.
Under MVS, records can be referenced by ID when you specify MACRF=(...I...) in
the DCB and the type parameter of the READ/WRITE macro contains I (see
Figure 42 on page 317).
VSE READ filename,KEY
KEYARG and KEYLEN operands are required in the DTFDA macro.
MVS READ decbname, DK,...,keyaddress,blockaddress
316 VSE to OS/390 Migration Workbook