Glossary: Glossary

Glossary

This glossary defines SAS software terms that are used in this document as well as terms that relate specifically to SAS/ACCESS software.

access descriptor

a SAS/ACCESS file that describes data that is managed by a data management system. After creating an access descriptor, you can use it as the basis for creating one or more view descriptors. See also view and view descriptor.

browsing data

the process of viewing the contents of a file. Depending on how the file is accessed, you can view SAS data either one observation (row) at a time or as a group in a tabular format. You cannot update data that you are browsing.

bulk load

to load large amounts of data into a database object, using methods that are specific to a particular DBMS. Bulk loading enables you to rapidly and efficiently add multiple rows of data to a table as a single unit.

client

(1) a computer or application that requests services, data, or other resources from a server. (2) in the X Window System, an application program that interacts with the X server and can perform tasks such as terminal emulation or window management. For example, SAS is a client because it requests windows to be created, results to be displayed, and so on.

column

in relational databases, a vertical component of a table. Each column has a unique name, contains data of a specific type, and has certain attributes. A column is analogous to a variable in SAS terminology.

column function

an operation that is performed for each value in the column that is named as an argument of the function. For example, AVG(SALARY) is a column function.

commit

the process that ends a transaction and makes permanent any changes to the database that the user made during the transaction. When the commit process occurs, locks on the database are released so that other applications can access the changed data. The SQL COMMIT statement initiates the commit process.

DATA step view

a type of SAS data set that consists of a stored DATA step program. Like other SAS data views, a DATA step view contains a definition of data that is stored elsewhere; the view does not contain the physical data. The view's input data can come from one or more sources, including external files and other SAS data sets. Because a DATA step view only reads (opens for input) other files, you cannot update the view's underlying data.

data type

a unit of character or numeric information in a SAS data set. A data value represents one variable in an observation.

data value

in SAS, a unit of character or numeric information in a SAS data set. A data value represents one variable in an observation.

database

an organized collection of related data. A database usually contains named files, named objects, or other named entities such as tables, views, and indexes

database management system (DBMS)

an organized collection of related data. A database usually contains named files, named objects, or other named entities such as tables, views, and indexes

editing data

the process of viewing the contents of a file with the intent and the ability to change those contents. Depending on how the file is accessed, you can view the data either one observation at a time or in a tabular format.

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 format. There are several types of engines.

file

a collection of related records that are treated as a unit. SAS files are processed and controlled by SAS and are stored in SAS libraries.

format

a collection of related records that are treated as a unit. SAS files are processed and controlled by SAS and are stored in SAS libraries. In SAS/ACCESS software, the default formats vary according to the interface product.

index

(1) in SAS software, 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. (2) in other software vendors' databases, a named object that directs the DBMS to the storage location of a particular data value for a particular column. Some DBMSs have additional specifications. These indexes are also used to optimize the processing of WHERE clauses and joins. Depending on the SAS interface to a database product and how selection criteria are specified, SAS might or might not be able to use the DBMS indexes to speed data retrieval.

Depending on how selection criteria are specified, SAS might use DBMS indexes to speed data retrieval.

informat

a pattern or set of instructions that SAS uses to determine how data values in an input file should be interpreted. SAS provides a set of standard informats and also enables you to define your own informats.

interface view engine

a SAS engine that is used by SAS/ACCESS software to retrieve data from files that have been formatted by another vendor's software. Each SAS/ACCESS interface has its own interface view engine. Each engine reads the interface product data and returns the data in a form that SAS can understand--that is, in a SAS data set. SAS automatically uses an interface view engine; the engine name is stored in SAS/ACCESS descriptor files so that you do not need to specify the engine name in a LIBNAME statement.

libref

a name that is temporarily associated with a SAS library. The complete name of a SAS file consists of two words, separated by a period. The libref, which is the first word, indicates the library. The second word is the name of the specific SAS file. For example, in VLIB.NEWBDAY, the libref VLIB tells SAS which library contains the file NEWBDAY. You assign a libref with a LIBNAME statement or with an operating system command.

member

a SAS file in a SAS library.

member name

a name that is given to a SAS file in a SAS library.

member type

a SAS name that identifies the type of information that is stored in a SAS file. Member types include ACCESS, DATA, CATALOG, PROGRAM, and VIEW.

missing value

in SAS, a term that describes the contents of a variable that contains no data for a particular row or observation. By default, SAS prints or displays a missing numeric value as a single period, and it prints or displays a missing character value as a blank space.

observation

a row in a SAS data set. All data values in an observation are associated with a single entity such as a customer or a state. Each observation contains one data value for each variable. In a database product table, an observation is analogous to a row. Unlike rows in a database product table or file, observations in a SAS data file have an inherent order.

PROC SQL view

a SAS data set (of type VIEW) that is created by the SQL procedure. A PROC SQL view contains no data. Instead, it stores information that enables it to read data values from other files, which can include SAS data files, SAS/ACCESS views, DATA step views, or other PROC SQL views. A PROC SQL view's output can be either a subset or a superset of one or more files.

query

a set of instructions that requests particular information from one or more data sources.

referential integrity

a set of rules that a DBMS uses to ensure that a change to a data value in one table also results in a change to any related values in other tables or in the same table. Referential integrity is also used to ensure that related data is not deleted or changed accidentally.

relational database management system

a database management system that organizes and accesses data according to relationships between data items. Oracle and DB2 are examples of relational database management systems.

rollback

in most databases, the process that restores the database to its state when changes were last committed, voiding any recent changes. The SQL ROLLBACK statement initiates the rollback processes. See also commit.

row

in relational database management systems, the horizontal component of a table. A row is analogous to a SAS observation.

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. A PROC SQL table is a SAS data file. SAS data files are of member type DATA.

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

SAS/ACCESS views

See view descriptor and SAS data view.

SAS library

a collection of one or more SAS files that are recognized by SAS and that are referenced and stored as a unit. Each file is a member of the library.

server

in a network, a computer that is reserved for servicing other computers in the network. Servers can provide several different types of services, such as file services and communication services. Servers can also enable users to access shared resources such as disks, data, and modems.

SQL pass-through facility

a group of SQL procedure statements that send and receive data directly between a relational database management system and SAS. The SQL pass-through facility includes the CONNECT, DISCONNECT, and EXECUTE statements, and the CONNECTION TO component. SAS/ACCESS software is required in order to use the SQL pass-through facility.

Structured Query Language (SQL)

the standardized, high-level query language that is used in relational database management systems to create and manipulate database management system objects. SAS implements SQL through the SQL procedure.

table

a two-dimensional representation of data, in which the data values are arranged in rows and columns.

trigger

a type of user-defined stored procedure that is executed whenever a user issues a data-modification command such as INSERT, DELETE, or UPDATE for a specified table or column. Triggers can be used to implement referential integrity or to maintain business constraints.

variable

a column in a SAS data set. A variable is a set of data values that describe a given characteristic across all observations.

view

a definition of a virtual data set. The definition is named and stored for later use. A view contains no data. It merely describes or defines data that is stored elsewhere. The ACCESS and SQL procedures can create SAS data views.

view descriptor

a file created by SAS/ACCESS software that defines part or all database management system (DBMS) data or PC file data that an access descriptor describes. The access descriptor describes the data in a single DBMS table, DBMS view, or PC file.

wildcard

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