Glossary: Glossary

Glossary

arithmetic operator: any of the symbols (+, -, /, *, and **) that are used to perform addition, subtraction, division, multiplication, or 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, result 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 or tables. See also outer join.
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 and outer join.
library engine: an engine that accesses groups of files and puts them in 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 (library reference): 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.
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 contain operators, variables, and constants.
operator: in a SAS expression, any of several symbols that request a comparison, a logical operation, or an arithmetic calculation.
outer join: in the SQL procedure, an inner join that is augmented with rows that do not match any row from the other table or tables 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, SAS formats and 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 that are stored 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 SAS DATA step and by the SAS SQL procedure.
SQL (Structured Query Language): a standardized, high-level query language that is used in relational database management systems to create and manipulate objects in a database management system. SAS implements SQL through the SQL procedure.
summary function: a function that summarizes or describes a group of data values, which are usually 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 typically 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 generic term (used by many software vendors) for a definition of a virtual data set (or table). The definition is named and stored for later use. A view contains no data; it merely describes or defines data that is stored elsewhere.
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.

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