Glossary of Terms for Migration Issues
- audit trail
- an optional SAS file that you can create in order to log modifications to a SAS data file. Each time an observation is added, deleted, or updated, information is written to the audit trail about who made the modification, what was modified, and when.
- CEDA (Cross-Environment Data Access)
- a feature of SAS software that enables a SAS data file that was created in any directory-based operating environment (for example, Solaris, Windows, HP-UX, OpenVMS Alpha) to be read by a SAS session that is running in another directory-based environment. You can access the SAS data files without using any intermediate conversion steps.
See also data representation.
- computer architecture
- the manner in which numeric data and character data are represented internally in a particular operating environment. Architecture encompasses standards or conventions for storing floating-point numbers (IEEE or IBM 390); for character encoding (ASCII or EBCDIC); for the ordering of bytes in memory (big Endian or little Endian); for word alignment (4-byte boundaries or 8-byte boundaries); and for data-type length (16-bit, 32-bit, or 64-bit).
- data representation
- the form in which data is stored in a particular operating environment. Different operating environments use different standards or conventions for storing floating-point numbers (for example, IEEE or IBM 390); for character encoding (ASCII or EBCDIC); for the ordering of bytes in memory (big Endian or little Endian); for word alignment (4-byte boundaries or 8-byte boundaries); and for data-type length (16-bit, 32-bit, or 64-bit).
- encoding
- a set of characters (letters, logograms, digits, punctuation, symbols, control characters, and so on) that have been mapped to numeric values (called code points) that can be used by computers. The code points are assigned to the characters in the character set by applying an encoding method. Some examples of encodings are wlatin1, wcyrillic, and shift-jis.
- engine
- a component of SAS software that reads from or writes to a file. Each engine enables SAS to access files that are in a particular file format. There are several types of engines.
- foreign file format
- a relative term that contrasts the internal data representation of a file with that of an operating environment. If the internal formats are not the same, the file format is considered to be foreign to the operating environment. For example, the format of a file that is created in an OS/390 or z/OS operating environment is considered to be foreign to Windows operating environments. Foreign file formats are also referred to as non-native file formats.
See also native file format.
- generation data set
- an archived copy of a SAS data set. Multiple copies of a SAS data set can be kept by requesting the generations feature. The multiple copies represent versions of the same data set, which are archived each time the data set is replaced. The copies are referred to as a generation group and are a collection of data sets that have the same root member name but different version numbers. There is a base version, which is the most recent version, plus a set of historical versions.
- index
- a component of a SAS data set that enables SAS to access observations in the SAS data set quickly and efficiently. The purpose of SAS indexes is to optimize WHERE-clause processing and to facilitate BY-group processing.
- integrity constraints
- a set of data validation rules that you can specify in order to restrict the data values that can be stored for a variable in a SAS data file. Integrity constraints help you preserve the validity and consistency of your data.
- migrate
- in the MIGRATE procedure, to convert data to a different format for use with a newer version of SAS. In addition, migration can include moving the data to a different server or storage device, converting the data for use in a different operating environment, or both. In a broader sense, the migration process can also include installing the newer software and converting applications for use with that software.
- mixed-mode directory
- a directory that contains files from more than one version of SAS software. For example, a directory that contains files from Version 6 and Version 8 is a mixed-mode directory.
- native file format
- a relative term that compares the internal data representation of a file with that of an operating environment. If the internal formats are the same, the file format is considered to be native to the operating environment. For example, the format of a file that is created in a 32-bit Windows operating environment is considered to be native to other 32-bit Windows operating environments.
See also foreign file format.
- open mode
- the way in which a SAS task accesses and operates on a member in a SAS library. There are three open modes for SAS files: input, update, and output.
See also control level, locking.
- operating environment family
- a group of operating environments that are compatible with one another. Operating environment compatibility is usually dependent on computer architecture, but a software application can also affect compatibility. Therefore, the operating environments that are included in a family depend both on the architecture and on the software that is in use.
- SAS catalog
- a SAS file that stores many different kinds of information in smaller units called catalog entries. A single SAS catalog can contain several different types of catalog entries.
- SAS data file
- a type of SAS data set that contains data values as well as descriptor information that is associated with the data. The descriptor information includes information such as the data types and lengths of the variables, as well as the name of the engine that was used to create the data.
See also SAS data set, SAS data view.
- SAS data library
- a collection of one or more SAS files that are recognized by SAS and which are referenced and stored as a unit. Each file is a member of the library.
- SAS data set
- a file whose contents are in one of the native SAS file formats. There are two types of SAS data sets: SAS data files and SAS data views. SAS data files contain data values in addition to descriptor information that is associated with the data. SAS data views contain only the descriptor information plus other information that is required for retrieving data values from other SAS data sets or from files whose contents are in other software vendors' file formats.
- SAS data view
- a type of SAS data set that retrieves data values from other files. A SAS data view contains only descriptor information such as the data types and lengths of the variables (columns), plus other information that is required for retrieving data values from other SAS data sets or from files that are stored in other software vendors' file formats. SAS data views can be created by the ACCESS and SQL procedures, as well as by the SAS DATA step.
- source library
- the SAS library from which you move a SAS file.
- source operating environment
- in the context of moving and accessing SAS files, the operating environment from which you move a SAS file.
- target library
- the SAS library to which you move or copy a SAS file.
- target operating environment
- in the context of moving and accessing SAS files, the operating environment to which you move a SAS file.
- V6 compatibility engine
- an engine that can process Version 6 SAS files in SAS 9 without converting the files to the SAS System 9 file format.
See also engine.
