Glossary

access mode

the particular database management system (DBMS) that the SQL Query Window is configured to query.

arithmetic operator

any of the symbols (+, -, /, *, and **) that are used to perform addition, subtraction, division, multiplication, and exponentiation in SAS expressions.

automatic join

a feature of the SQL Query Window that enables you to predefine join criteria for a specific set of tables. When you select these tables for a query in a future session, the join criteria are already defined and are ready for use.

automatic lookup

a feature of the SQL Query Window that automatically displays the values of a particular column when that column is selected in the WHERE EXPRESSION window.

automatic lookup table

a SAS data set that stores information that the SQL Query Window uses to determine how to perform automatic lookup.

See also automatic lookup.

calculated column

in a query, a column that does not exist in any of the tables that are being queried, but which is created as a result of a column expression.

See also column expression.

catalog

See SAS catalog.

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 alias

a temporary, alternate name for a column. Aliases are optionally specified in the SQL procedure's SELECT clause to name or rename columns . An alias is one word.

See also column.

column expression

a set of operators and operands that, when evaluated, results in a single data value. The resulting data value can be either a character value or a numeric value.

descriptive statistic

a quantity that characterizes, rather than draws inference from, a collection of values. Types of descriptive statistics are measures of central tendency, measures of variation among values, and measures of the shape of the distribution of values.

format

a pattern or set of instructions that SAS uses to determine how the values of a variable (or column) should be written or displayed. SAS provides a set of standard formats and also enables you to define your own formats.

group

in the SQL procedure, a set of rows that all have the same combination of values for the columns that are specified in a GROUP BY clause.

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.

inner join

See join.

join

in the SQL procedure, the combination of data from two or more tables (or from two or more SAS data views) to produce a single result table. A conventional join, which is often called an inner join, returns a result table for all the rows in one table that have one or more matching rows in the other table(s).

See also outerjoin.

join criteria

the set of parameters that determine how tables are to be joined. Join criteria are usually specified in a WHERE expression or in an SQL ON clause.

See also join.

See also outerjoin.

library engine

an engine that accesses groups of files and puts them into the correct form for processing by SAS utility windows and procedures. A library engine also determines the fundamental processing characteristics of the library and presents lists of files for the library directory.

libref

a name that is temporarily associated with a SAS data 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.

logical operator

an operator that is used in expressions to link sequences of comparisons. The logical operators are AND, OR, and NOT.

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. In the SQL procedure, a missing value is equivalent to an SQL NULL value.

null value

a special value that indicates the absence of information. Null values are analogous to SAS missing values.

operand

any of the variables and constants in a SAS expression that contains operators, variables , and constants.

operator

in a SAS expression, any of several symbols that request a comparison, a logical operation, or an arithmetic calculation.

outerjoin

in the SQL procedure, an inner join that is augmented with rows that do not match with any row from the other table(s) in the join. There are three kinds of outer joins: left, right, and full.

See also join.

profile

a set of parameters that control the behavior of the SQL Query Window.

query

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

row

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

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.

See also SAS catalog entry.

SAS catalog entry

a separate storage unit within a SAS catalog. Each entry has an entry type that identifies its purpose to SAS. Some catalog entries contain system information such as key definitions. Other catalog entries contain application information such as window definitions, Help windows, formats, informats, macros, or graphics output.

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.

SQL(Structured Query Language)

a 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.

summary function

a function that summarizes or describes a group of data values, which usually are numeric data values. For example, SUM and MEAN are summary functions.

See also descriptive statistic.

summary report

a report that provides a concise overview of information that is derived from one or more data sources. Summary information is usually calculated using descriptive statistics such as SUM, MEAN, and RANGE.

See also descriptive statistic.

table

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

table source

a collection of one or more data sources to be queried.

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. SAS data views can be created by the ACCESS and SQL procedures.

WHERE expression

a type of SAS expression that specifies a condition for selecting observations for processing by a DATA step or a PROC step. WHERE expressions can contain special operators that are not available in other SAS expressions. WHERE expressions can appear in a WHERE statement, a WHERE= data set option, a WHERE clause, or a WHERE command.