Moving and Accessing SAS Files across Operating Environments

Regressing SAS Data Sets from Version 8 to Version 6 Format

The only traditional method for regressing a data set from Version 8 to Version 6 is by using PROC COPY. However, if SAS/CONNECT is licensed, you can use PROC UPLOAD and PROC DOWNLOAD to regress a data set.

Version 8 support of long variable names, long variable labels, and long data set labels may make Version 8 data sets incompatible with Version 6 data sets. In order to revert back to Version 6, these long names must be truncated to a length that is supported in Version 6. Here are the truncation rules:

Version 8 Data Set Object Names to Regress Truncates to x characters for Version 6

Data set labels 40

Variable labels 40

Variable names 8

Version 8 Data Set Object Names to Regress	Truncates to x characters for Version 6
Data set labels	40
Variable labels	40
Variable names	8

In order to transport Version 8 files back to Version 6, set the portable VALIDVARNAME system option to the value V6 in the SAS session in which you are transporting the file. Here are examples, which are specified in the form of a SAS system option and a macro variable:

options VALIDVARNAME=V6
%let VALIDVARNAME=V6;

For details about setting the VALIDVARNAME system option, see SAS Language Reference: Dictionary.

The truncation algorithm that is used to produce the 8-character variable name also resolves conflicting names:

The first name that is greater than 8 characters is truncated to 8 characters. A truncation from PROPERTYTAXRATE to PROPERTY is the first truncation.
The next name that is greater than 8 characters is truncated to 8 characters. If it conflicts with an existing variable name, it is truncated to 7 characters, and a suffix of 2 is added. For example, PROPERTYTAXRATE is truncated to PROPERT2.
The suffix is increased by 1 for each truncated name that conflicts with an existing name. If the suffix reaches 9, the next conflicting variable name is truncated to 6 characters, and a suffix of 10 is appended. For example, PROPERTYTAXRATE is truncated to PROPER10.

The VALIDVARNAME option solves the long variable name truncation problem. However, there are no techniques for regressing these Version 8 features to Version 6:

Data set names that exceed 8 characters
Integrity constraints
Data set generations.

The solution to regressing data sets with these features is to re-create the data sets without the Version 8 features in a Version 8 session.

Note: No traditional methods support regressing catalogs from Version 8 to Version 6. However, SAS/CONNECT does support moving some catalog entries from Version 8 to Version 6. See Using SAS/CONNECT to Transport Files between Hosts for details. [cautionend]

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