VSAM data sets can be defined by using either a DD statement, an environment variable, or the TITLE option of the OPEN statement.
When an environment variable or TITLE option is used, the name must be in uppercase. Specify the MVS data set as follows:
data set-name must be fully qualified and cannot be a temporary data set, for example, it must not start with &.
One of the following attributes must be specified after the DSN keyword: