The MFX Dictionary Feature allows you to create symbolic ‘dictionary_names’ for fields, constants, or output columns, and use these dictionary_names in MFX control statements.
Using the Dictionary Feature has many benefits:
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Easier coding of control statements speeds development of applications and improves accuracy.
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More readable and understandable control statements facilitate debugging and adaptation to changes in the future.
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Reducing or eliminating changes to control statements when record layouts change saves time and reduces errors.
To use the MFX Dictionary Feature, do the following:
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Build a symbols dictionary using the dictionary statements. A dictionary statement creates a dictionary_name and associates it with a constant value, field specification (position, length, format), or a parsed field.
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Activate the Dictionary Feature using the SYMNAMES DD statement. This DD tells MFX the name and location of the symbols dictionary to use. You can include multiple dictionaries by concatenating data sets.
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Use dictionary_names in control statements.
You may also use JCL statements with SET symbols or PROC symbols to establish dictionary_names. See Using JCL SET and PROC Symbols to Create Dictionary_Names.
A dictionary consists of one or more dictionary statements. A dictionary can be a sequential data set, a member of a PDS, or it can be placed immediately after the SYMNAMES DD statement (DD *).
Each time MFX executes with the Dictionary Feature activated by the SYMNAMES DD, it reads the dictionary statements from the symbols dictionary, and substitutes any dictionary_name found in the following control statements with the associated field specification or constant.
When a record layout changes, just modify the dictionary statements. The next sort execution will read in the updated dictionary statements and apply the new values during dictionary_name substitutions.