SAS session metadata
is stored in Dictionary tables, which are special, read-only SAS tables
that contain information about SAS libraries, SAS macros, and external
files that are available in the current SAS session. A Dictionary
table also contains the settings for SAS system options and SAS titles
and footnotes that are currently in effect.
Accessing a Dictionary
table causes PROC SQL to determine the current state of the SAS session
and return the information that you want. Dictionary tables can be
accessed by running a PROC SQL query against the table, using the
Dictionary libref. You can also access a Dictionary table by referring
to the PROC SQL view of the table that is stored in the Sashelp library.
To see how each Dictionary
table is defined, submit a DESCRIBE TABLE statement. After you know
how a table is defined, you can use its column names in a subsetting
WHERE clause in order to retrieve specific information. To display
information about the files in a specific library, specify the column
names in a SELECT statement and the dictionary table name in the FROM
clause. You can also use Dictionary tables to determine more specific
information such as which tables in a SAS library contain a specific
column.