Glossary: Glossary

Glossary

access authority: a code that associates a secondary password with a database component and that determines what kind of access to the database component the password can have. There are four types of access authority: R (retrieval), U (update), W (where-clause), and N (no access).
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, view descriptor.
ancestor: a record on the level that precedes a specified record in the same path.
authority: See access authority.
batch mode: a method of executing SAS programs in which a file that contains SAS statements plus any necessary operating environment commands is submitted to the computer's batch queue. After you submit the program, control returns to your personal computer, where you can perform other tasks. Batch mode is sometimes referred to as running in the background. The program output can be written to files or printed on an output device.
C-number: See component number.
children: the records that immediately follow a specified record.
component: a schema item, schema record, string, or function that is stored in a SYSTEM 2000 database definition. A component has a component number and a component name. See also component name, component number.
component name: a unique name that is assigned to a component in a SYSTEM 2000 database definition. See also component.
component number: a unique number that is assigned to a component in a SYSTEM 2000 database definition. Component numbers are also referred to as C- numbers. See also component.
condition: a part of a SYSTEM 2000 where-clause that contains an EXISTS, FAILS, EQ, NE, SPANS, LT, GT, LE, GE, or CONTAINS operator (or an equivalent symbol) and its operands, which are either schema items or specified values. See also expression.
connecting string: optional syntax that you can use in a SYSTEM 2000 where-clause that is included in a SAS/ACCESS view descriptor. A connecting string tells the interface view engine how you want to connect conditions in the SYSTEM 2000 where-clause with conditions that are translated from a SAS WHERE clause.
data management software: an integrated software application that enables you to create and manipulate data in the form of databases.
data record: an identifiable set of values that are treated as a unit and which are associated with a schema record. A logical entry consists of related data records. See also logical entry, schema record (SR).
data value: (1) in SAS software, a unit of character or numeric information in a SAS data set. A data value represents one variable in an observation. (2) in SYSTEM 2000 software, a character, numeric, or date value that is stored in one item in a data record.
database: an organized collection of interrelated data. In SYSTEM 2000 software, a database stores data according to a hierarchical structure that is specified in the database definition. See also database definition.
database definition: a blueprint for the type of data that will be stored in a SYSTEM 2000 database. A definition consists of schema records and related schema items, which are organized in a hierarchical structure. A definition labels the data to be stored, arranges the data into groups, and establishes relationships among the groups of data. See also schema record (SR), schema item.
DBA password: a SYSTEM 2000 password that provides a level of authority between that of the master password and that of the secondary passwords. The DBA password enables the DBA to administer databases without being able to access the data that is stored in them.
definition: See database definition.
descendant: a record that is at a lower level than a specified record in a family. A record is a descendant of all its ancestors.
descriptor file: a type of SAS/ACCESS file that is used to establish a connection between SAS and files that are created and maintained by other software applications. Descriptor files describe data to SAS. To create descriptor files, you use the ACCESS procedure. There are two types of descriptor files: access descriptors and view descriptors. See also access descriptor, view descriptor.
descriptor information: information about the contents and attributes of a SAS data set. For example, the descriptor information includes the data types and lengths of the variables, as well as which engine was used to create the data. SAS creates and maintains descriptor information within every SAS data set.
disjoint records: schema records that belong to different paths in a SYSTEM 2000 database definition.
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. See also interface view engine.
entry: See logical entry.
exclusive use: the condition under which only one user can access a database at a time.
expression: a part of a SYSTEM 2000 where-clause that contains a logical operator (AND, OR, NOT, HAS, or AT, or an equivalent symbol) and its operands, which are where-clause conditions. See also condition.
family: a SYSTEM 2000 record, all its ancestors, and all its descendants.
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 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.
function: an arithmetic calculation that is stored in a SYSTEM 2000 database definition.
hierarchical data management software: software that stores and accesses data according to a database structure that minimizes redundancy of stored data by organizing data in levels. SYSTEM 2000 databases have hierarchical structures. See also level.
index: in SAS software, a component of a SAS data set that enables SAS to access observations in the SAS data set quickly and efficiently. In SYSTEM 2000 software, values are indexed if the associated item is specified as a key item. Indexed values provide more efficient access than non-indexed values. If an item is not a key item, values are not indexed, but they can be searched sequentially.
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.
interactive line mode: a method of running SAS programs in which you enter one line of a SAS program at a time at the SAS session prompt. SAS processes each line immediately after you press the ENTER or RETURN key. Procedure output and informative messages are returned directly to your monitor.
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, which 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.
item: See schema item.
item type: a classification of values that determines how the values will be stored in a SYSTEM 2000 database. The item types are CHARACTER, TEXT, INTEGER, DECIMAL, MONEY, DATE, REAL (or FLOAT), DOUBLE, and UNDEFINED.
level: an aspect of the hierarchical structure of a SYSTEM 2000 database. Each schema record is placed at a particular level, thus reflecting a hierarchical structure. For example, the ENTRY record is at level 0. Records that are directly beneath the ENTRY record are at level 1, and so on. The corresponding data records also reflect the hierarchical structure.
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. F or 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 entry: the data records that pertain to one entry in a SYSTEM 2000 database. For example, in the EMPLOYEE database, all data records that pertain to one employee comprise a logical entry.
master password: the password under which a SYSTEM 2000 database is created. The holder of the master password can access the entire database and has the authority to use any SYSTEM 2000 statement.
member: a SAS file in a SAS library.
member name: a name that is assigned to a SAS file in a SAS library. See also member type.
member type: a SAS name that identifies the type of information that is stored in a SAS file. Member types include ACCESS, DATA, CATALOG, ITEMSTOR, MDDB, 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. In SYSTEM 2000 software, missing values are called nulls. See also null item, null record.
multi-user environment: a SYSTEM 2000 execution environment in which many users access a database concurrently, with queries and updates handled simultaneously by one copy of the software. See also single-user environment.
null item: an item for which space is allocated in a record, although no value currently exists in the SYSTEM 2000 database. A null item is similar to a SAS missing value, but they are not identical. See also missing value, schema item.
null record: a data record that contains all null items.
observation: a row in a SAS data set. All of the 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.
ordering-clause: a set of one or more user-specified SYSTEM 2000 schema items that control the sorting of selected values.
parent: a record that immediately precedes another record.
password: a string of characters that a user must specify correctly in order to access a database. The passwords protect the database from unauthorized access. In SYSTEM 2000, there are three types of passwords: master, secondary, and DBA.
path: a record and all its ancestors in a SYSTEM 2000 database. Schema records are disjoint if they are not in the same path.
picture: the logical size (length) of values in a SYSTEM 2000 database. A picture is specified for each schema item.
R-authority: a code that is specified by the holder of the master password and which gives the holder of a secondary password the authority to retrieve a SYSTEM 2000 schema component.
record: See data record, schema record.
rollback: a recovery method that is used by SYSTEM 2000 to automatically reinstate a database after a hardware or software failure. The Rollback Log, which contains 'before' images, and the Update Log, which contains journaled updates, provide SYSTEM 2000 with the information that is needed for returning the database to undamaged status.
SAS data file: a 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 which engine was used to create the data. SAS data files are of member type DATA. See also SAS data set, SAS view.
SAS 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 views. SAS data files contain data values in addition to descriptor information that is associated with the data. SAS 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. See also descriptor information.
SAS view: a type of SAS data set that retrieves data values from other files. A SAS 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 views are of member type VIEW.
schema item: a component that specifies the name and characteristics of a group of SYSTEM 2000 database values. That is, a schema item has a name, a type, and a picture (length). Each value stored in a SYSTEM 2000 database corresponds to a schema item. A SYSTEM 2000 schema item is analogous to a SAS variable.
schema record (SR): an identifiable set of associated schema items that are treated as a unit in a SYSTEM 2000 database.
secondary password: a password, other than the master password or DBA password, that restricts SYSTEM 2000 statement usage and which specifically assigns update, retrieval, and where-clause authorities for any or all components of a SYSTEM 2000 database.
single-user environment: a SYSTEM 2000 execution environment in which you are working with your own copy of SYSTEM 2000 software. In a single-user environment, you usually have exclusive access to the database. However, the single-user environment can be configured so that multiple users can query the database. See also multi-user environment.
stored string: a text string that is contained in a SYSTEM 2000 database definition and which can be invoked by using the string number or name.
U-authority: a code that is set by the holder of the master password and which gives the holder of a secondary password the authority to update a SYSTEM 2000 schema item or schema record.
variable: a column in a SAS data set or in a SAS view. The data values for each variable describe a single characteristic for all observations. Each SAS variable can have the following attributes: name, data type (character or numeric), length, format, informat , and label. In the ACCESS procedure, variables are created from SYSTEM 2000 item names.
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 views can be created by the ACCESS and SQL procedures. See also SAS view.
view descriptor: a SAS/ACCESS file that defines a subset of a database that is described by an access descriptor. The subset consists of selected items in a given path of one SYSTEM 2000 database, with optional selection criteria and ordering criteria. See also access descriptor.
W-authority: a code that is set by the holder of the master password and which gives the holder of a secondary password the authority to use SYSTEM 2000 schema items or schema records for selection criteria in a where-clause.
where-clause: a set of one or more conditions that users specify as selection criteria for SYSTEM 2000 updates or retrievals.

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