Moving and Accessing SAS Files across Operating Environments

Transporting SAS Files between Versions

The data transfer services in SAS/CONNECT also moves data between versions of SAS software as well as across hosts. Many organizations may find it necessary to operate in a mixed-version environment while making a transition from Version 6 to Version 8. This environment includes a mixture of local or remote hosts running either a Version 6 session or a Version 8 session.

Whenever possible, it is generally recommended that you keep Version 6 and Version 8 SAS files in separate physical locations. This will avoid any potential confusion as to which file is being accessed. If mixed versions are stored in the same library, the appropriate engine should be specified when accessing the SAS data files. For more details about operating in a mixed library environment, see Using SAS/SHARE to Access Remote Files.

Cross-Version Compatibility

Version 8 offers several new features that make Version 8 data files incompatible with Version 6 data files. However, for new features that involve increased character length, SAS/CONNECT truncates 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 Version 8 features while operating in a mixed-version environment. The Version 8 features that SAS/CONNECT is able to truncate are:

long data set labels
long variable labels
long variable names.

Other new 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.

Truncating Version 8 Data Set Names for Version 6 Access

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

SAS/CONNECT applies the truncation rules during file transfer

from a Version 8 session to a Version 6 session.
between two Version 8 sessions (including a Version 7 session and a Version 8 session) to produce a Version 6 data file.
Note: In order to produce a Version 6 data file, you set the SAS option and value VALIDVARNAME=V6 in the session that creates the data file. With VALIDVARNAME=V6 set, the truncation is performed when running the V8 engine or the V6 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 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, STOCKNUMBER63 is truncated to STOCKN10.

Version 6 Local Host Accessing a Version 8 Remote Host

This section summarizes the limitations of a Version 6 local host that accesses files on a Version 8 remote host in a cross-version environment.

SAS Data Files

All data format conversions are performed when transferring a data file and do not require any user invention. PROC UPLOAD produces a Version 8 data file when transferring data files from a Version 6 local host. PROC DOWNLOAD provides full support for the transfer of Version 6 data files residing on the remote host. However, Version 8 data files can be downloaded to a Version 6 local host and will follow the truncation rules provided that the data files do not contain any other Version 8 specific features.

SAS SQL Views

In order to upload or download PROC SQL views, a Version 6 local host can use the DATA= option in the procedure to specify the data file that is associated with the view to be transferred. Alternatively, the Version 6 local host can use the INLIB= option in the procedure to specify the library for transfer.

SAS Catalogs

A Version 6 local host can upload a Version 6 catalog, but the resulting catalog is in Version 8 format. A Version 6 host can download Version 6 or Version 8 catalogs as long as the entry type is backwards compatible.

Version 8 Local Host Accessing a Version 6 Remote Host

This section summarizes the limitations of a Version 8 local host that accesses files on a Version 6 remote host in a cross-version environment.

SAS Data Sets

A Version 8 data set can be uploaded to a Version 6 remote host and will follow the truncation rules describe earlier, provided that the data sets do not contain any other Version 8 specific features. PROC DOWNLOAD transfers Version 6 data sets to the Version 8 local host.

SAS SQL Views

A Version 8 local host can upload data that is associated with a view to a Version 6 remote host and will follow the truncation rules.

SAS Catalogs

A Version 8 local host can download a Version 6 catalog from a Version 6 remote host. A Version 6 catalog can also be uploaded from the Version 8 local host if the entry type is backward compatible.

Note: The Version 8 local host cannot use PROC UPLOAD to create a Version 6 catalog entry because Version 6 catalogs are read-only in Version 8. [cautionend]

Version 6-Version 8 Compatible Catalog Entry Types

Note: Version 8 cannot read Version 6 catalogs on an AIX UNIX host. In order to move Version 6 catalogs to Version 8 format on AIX hosts, you must use PROC CPORT and PROC CIMPORT. [cautionend]

SAS/CONNECT supports moving some catalog entries between Version 8 and Version 6. Version 8 entry types that are backward compatible with Version 6 are:

DEVMAP FONT FONTLIST

KEYMAP KEYS LOG

OUTPUT SOURCE TEMPLATE

TRANTAB

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