You define a sequential VSAM data set by using a file declaration with the following attributes:
DCL filename FILE RECORD
INPUT | OUTPUT | UPDATE
SEQUENTIAL
BUFFERED
[KEYED]
ENVIRONMENT(options);
You define a direct VSAM data set by using a file declaration with the following attributes:
DCL filename FILE RECORD
INPUT | OUTPUT | UPDATE
DIRECT
[KEYED]
ENVIRONMENT(options);
Table 13 shows the default attributes. The file attributes are described in the PL/I Language Reference. Options of the ENVIRONMENT attribute are discussed below.
Some combinations of the file attributes INPUT or OUTPUT or UPDATE and DIRECT or SEQUENTIAL or KEYED SEQUENTIAL are allowed only for certain types of VSAM data sets. Figure 34 shows the compatible combinations.