SAS/CONNECT User's Guide

Cross-Version Compatibility

Version 7 and Version 8 of SAS offer several new features that affect the file format of data files. These features make Version 7 and Version 8 data files incompatible with Version 6 data files. However, for new features that involve increased character length, SAS/CONNECT will truncate the character length in an attempt to produce a Version 6 compatible data file. This allows you to take advantage of some of the new features while operating in a mixed-version environment. The new Version 7 or Version 8 features that SAS/CONNECT is able to truncate include:

long data set labels
long variable labels
long variable names.

Other new Version 7 or Version 8 features cannot be modified to make data files compatible with Version 6. Therefore, any attempt to transfer data files that contain these features will fail. Some of the new features that cannot be modified to be Version 6 compatible include:

data set generations
integrity constraints.

For complete information about Version 7 or Version 8 features, see SAS Language Reference: Concepts.

Truncating Version 7 or Version 8 Data Sets for Version 6 Access

Version 7 and Version 8 of SAS support longer names and labels than those supported in Version 6. The longer names and labels are stored in Version 7 or Version 8 data files, which make them incompatible with Version 6. SAS/CONNECT implements a set of truncation rules to convert a Version 7 or Version 8 data file that contains long names and labels back into a Version 6 data file.

The truncation rules are applied when using SAS/CONNECT to transfer files

from a Version 7 or Version 8 session to a Version 6 session.
between two Version 7 or Version 8 sessions and to produce a Version 6 data file.
Note: A Version 6 data file is produced by specifying VALIDVARNAME=V6 in the session that creates the data file. If VALIDVARNAME=V6 is set, the truncation is performed when running either the Version 7 or Version 8 engine or the Version 6 engine.

In either case, the following rules are applied for data sets that have long data set labels, long variable labels, and/or long variable names. In each case, the length is truncated to the length that is supported by Version 6.

Data set labels are truncated to 40 characters.
Variable labels are truncated to 40 characters.
Variable names are truncated to 8 characters.
Note: If the variable label field is blank, the long variable name is copied to the label field.

The truncation algorithm that is used to produce the 8-character variable name also resolves conflicting names.
1. The first name that is greater than 8 characters is truncated to 8 characters. For example, STOCKNUMBER53 is truncated to STOCKNUM.
2. 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, STOCKNUMBER54 is truncated to STOCKNU2.
3. The suffix is increased by one for each truncated name that results in a conflict. If the suffix reaches 9, the next conflicting variable name is truncated to 6 characters, and a suffix of 10 is appended. For example, STOCKNUMBER63 is truncated to STOCKN10.

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