Field and constant symbols overview

This chapter describes DFSORT's simple and flexible method for using symbols in DFSORT and ICETOOL statements. You can define and use a symbol for any field, constant, or output column that is recognized in a DFSORT control statement or ICETOOL operator. You can also use symbols for numbers associated with various keywords in DFSORT and ICETOOL statements. This makes it easy to create and reuse collections of symbols (that is, mappings) representing information associated with various record layouts.

In addition, you can obtain and use collections of DFSORT symbols created specifically for records produced by other products (for example, RACF®, DFSMSrmm and DCOLLECT) or by your site. Visit the DFSORT home page at the following URL to obtain information about downloading DFSORT symbol mappings for records produced by other products, and examples that use these symbols:

     http://www.ibm.com/storage/dfsort

Symbols can increase your productivity by automatically providing the positions, lengths and formats of the fields, the values of the constants, and the positions of the output columns associated with the particular records you are processing with DFSORT or ICETOOL.

You can even use system symbols (for example, &JOBNAME.) and SET and PROC symbols, in your symbol constants.

To use symbols for DFSORT or ICETOOL, you just:

Create or obtain the DFSORT symbol data sets you need. Symbol data sets contain symbols that map the fields in your records, and constants used for comparisons, titles, headings and so on. The symbols are specified in DFSORT's simple but flexible SYMNAMES statement format. Symbols can be easily added or modified using an editor, such as ISPF EDIT.
Include a SYMNAMES DD statement in your job. SYMNAMES specifies one or more symbol data sets (sequential, partitioned member, DD *) to be used for your DFSORT or ICETOOL application. SYMNAMES can be used to concatenate as many symbol data sets as you like.
Use the symbols from SYMNAMES where appropriate in DFSORT control statements or ICETOOL operators. You can mix symbols (for example, Last_Name) with regular fields (for example, p,m,f) and constants (for example, C'string').

DFSORT or ICETOOL will read SYMNAMES and use the symbols it contains to "transform" your statements by performing symbol substitution. DFSORT or ICETOOL will then use the transformed statements as if you had specified them directly.

If your record layout changes, just make a corresponding change to your DFSORT symbol data set. DFSORT will use the new mapping to "transform" your symbols correctly, even if positions change, so you won't have to change your statements. Be sure that your symbol definitions match your record layout before you attempt to use them.