|SAS/ACCESS Interface to SYSTEM 2000 Data Management Software: Reference|
|access descriptor||a SAS/ACCESS file that describes to the SAS System a single SYSTEM 2000 database. It is used as a master for creating view descriptors. See also view descriptor.|
|ancestor||a SYSTEM 2000 record that lies on a level above a specified record in the same path.|
|authority||a SYSTEM 2000 code that associates a password
with a database component and determines what kind of access to the database
the password can have. There are four kinds of authorities: R for retrieval,
U for update, W for where-clause, and N for no access. Authorities are associated
with secondary passwords.
A master password holder has full authority to the database.
|batch mode||a method of executing SAS programs in which you prepare a file containing SAS statements, or job control language (JCL) statements, and any necessary operating system commands, and submit the program to the computer's batch queue. Batch execution is completely separate from other activities at your terminal. It is sometimes referred to as running in background.|
|browsing data||the process of viewing a file. You may see the data one observation at a time or in a tabular format. You cannot update data that you are browsing.|
|C-number||the letter C followed by a SYSTEM 2000 component number, for example, C200.|
|component||a unique name assigned to a component in a SYSTEM 2000 database definition.|
|component number||a unique number assigned to a component in a SYSTEM 2000 database definition. Also referred to as a C-number.|
|condition||a part of a SYSTEM 2000 where-clause containing an EXISTS, FAILS, EQ, NE, SPANS, LT, GT, LE, GE, or CONTAINS operator (or an equivalent symbol) and its operands, which are items or given values. See also expression.|
|connecting string||optional syntax that you can use in a SYSTEM 2000 where-clause included in a view descriptor. A connecting string tells the interface view engine how you want to connect conditions in the SYSTEM 2000 where-clause with ones translated from a SAS WHERE clause. Some of the available connecting strings are: *SAS*, *ANDSAS*, *SASAND*, *ANDNK*, and so on.|
|database||an organized collection of interrelated data. In SYSTEM 2000 software, a database stores data according to a hierarchical structure specified in its definition. See also definition.|
|data management software||an integrated software package that enables you to create and manipulate data in the form of databases.|
|data record||an identifiable set of values treated as a unit and associated with a schema record in a SYSTEM 2000 database. A logical entry is made up of related data records.|
|data value||in the SAS System, a character or numeric
value that is stored in one variable in an observation, that is, the intersection
of a variable (vertical component) and an observation (horizontal component).
It refers to the actual data in a SAS data file, such as the value Smith
for the variable LASTNAME.
In a SYSTEM 2000 database, a character, numeric, or date value that is stored in one item in a data record.
|DBA password||a SYSTEM 2000 password that provides a level of authority between that of the master password and the secondary passwords. It allows the DBA to administer databases without being able to access the data stored in them.|
|definition||a blueprint for the type of data to be stored by a SYSTEM 2000 database. A definition is made up of schema records and related schema items, organized into a hierarchical structure. A definition labels the data to be stored, arranges the data into groups, and establishes relationships among the groups of data.|
|descendant||a SYSTEM 2000 record that lies below a specified record in a family. A record is a descendant of all its ancestors.|
|descriptor files||used to establish a connection between the SAS System and SYSTEM 2000 software. To create descriptor files, you use the ACCESS procedure. There are two types of descriptor files, access descriptors and view descriptors.|
|disjoint||schema records or items that belong to different paths in a SYSTEM 2000 database.|
|editing data||the process of viewing a file with the intention (and ability) of changing it. You can see the data one observation at a time or in a tabular format.|
|engine||components of the SAS System that read from or write to a file. Each engine allows the SAS System to access files with a particular format. See also interface view engine.|
|entry||See logical entry.|
|exclusive use||the state in which a SYSTEM 2000 database is used by one user only. Other users wanting to use the database must wait until exclusive use of the database is relinquished.|
|expression||a part of a SYSTEM 2000 where-clause containing an AND, OR, NOT, HAS, or AT operator (or an equivalent symbol) and its operands, which are where-clause conditions. See also condition.|
|family||the ancestors and descendants of a specified SYSTEM 2000 record.|
|file||a collection of related records treated
as a unit. SAS files are processed and controlled through the SAS System
and are stored in a SAS data library.
In SYSTEM 2000 software, each database contains six database files, which together hold the definition, the indexes, the values, and the hierarchical structure of the database. Database files 7 and 8 are optional files for the Update Log and Rollback Log.
|format, variable||a pattern the SAS System uses to display each character or numeric data value in a variable. The default format is BEST12. for numeric variables and $w. for character variables.|
|function||an arithmetic calculation stored in a SYSTEM 2000 database definition.|
|hierarchical data management software||software that stores and accesses data according to a database structure in which data are organized in levels, which minimizes redundancy of stored data. SYSTEM 2000 databases have hierarchical structures. See also level.|
|index||in the SAS System, a SAS file associated
with a SAS data file that enables you to access observations by index value.
Indexing usually makes data set processing faster, although the SAS System
determines the most efficient way to process data maintained by the SAS System.
In SYSTEM 2000 software, values are indexed if the associated item is specified as a key item. Indexed values provide more efficient access than nonindexed values. If an item is non-key, values are not indexed, although they can be searched sequentially.
|informat, variable||the pattern that the SAS System uses to read data values into a variable.|
|interactive line mode||an execution mode in which program statements are entered on the terminal at the SAS session prompt. Procedure output and informative messages are returned directly to your terminal display.|
|interface view engine||an engine that retrieves data directly from files formatted by other software vendors. The SAS/ACCESS interface to SYSTEM 2000 software includes an interface view engine.|
|item||See schema item.|
|item type||a classification according to the representation of the values to be stored in a SYSTEM 2000 database. SYSTEM 2000 software has the following item types: CHARACTER, TEXT, INTEGER, DECIMAL, MONEY, DATE, REAL (or FLOAT), DOUBLE, and UNDEFINED.|
|level||the organization of a SYSTEM 2000 database
in which each schema record is placed at a certain level, thus reflecting
a hierarchical structure.
For example, the ENTRY record is at level 0, records right below the ENTRY record are at level 1, and so on. The corresponding data records also reflect the hierarchical structure.
|libref||a temporary name that points to a SAS data library. A SAS file's complete name consists of two words separated by a period. The libref is the first word and indicates the library; the second word is the specific SAS file in the library. For example, in VLIB.NEWBDAY, VLIB is the libref and tells the SAS System where to look to find the file NEWBDAY.|
|logical entry||all related data records pertaining to one entry in a SYSTEM 2000 database. For example, in the EMPLOYEE database, all data records pertaining to one employee make up a logical entry. In SAS terms, an observation is one path in a logical entry; that is, one logical entry can produce multiple observations.|
|master password||the password under which a SYSTEM 2000 database is created. The user of the master password has access to the entire database and has the authority to use any SYSTEM 2000 statement.|
|member||a SAS file in a SAS data library.|
|member name||a name given to a SAS file in a SAS data library.|
|member type||a SAS name that identifies what type of information is stored in the file. Member types include access, data, catalog, program, and view.|
|missing value||a value in the SAS System indicating that
no data are stored for the variable in the current observation. By default,
the SAS System represents a missing numeric value with a single period and
a missing character value by a blank space.
In a SYSTEM 2000 database, missing values are called nulls. See null item and null record.
|Multi-User environment||the SYSTEM 2000 execution environment in which many users access a SYSTEM 2000 database at the same time, with queries and updates being 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. It is similar to the SAS System's missing value, although not identical.|
|null record||a data record with all null items.|
|observation||the horizontal component of a SAS data file. It is a collection of data values associated with a single entity, such as a customer or state. Each observation contains one data value for each variable in the data file.|
|ordering-clause||a set of one or more user-specified SYSTEM 2000 items that governs the sorting of selected values.|
|password||a string of characters that must be correctly specified by a user to gain access to a SYSTEM 2000 database. The passwords protect the database from unauthorized access. A password can be a master password, a secondary password, or a DBA password.|
|path||a record and all its ancestors in a SYSTEM 2000 database. Schema records and data records are disjoint if they are not in the same path.|
|picture||the logical size (or length) of values in a SYSTEM 2000 database, specified for each schema item.|
|R-authority||a code that gives a secondary password the authority to retrieve a SYSTEM 2000 schema component; set by the master password holder.|
|record||See schema record and data record.|
|rollback||a recovery method whereby SYSTEM 2000 software can automatically reinstate a database after a hardware or software failure. The Rollback Log of before images and the Update Log of journaled updates provide SYSTEM 2000 software all the information needed to recover the database to an undamaged status.|
|SAS data file||one of the formats of a SAS data set. A
SAS data file contains both data values and descriptor information associated
with the data, such as the variable attributes. In previous releases of the
SAS System, all SAS data sets were SAS data files. SAS data files are of
the member type DATA.
A SAS data file is arranged in a rectangular, two-dimensional format. Each item in a SAS data file is called a data value. Data values in a row comprise an observation and those in a column comprise a variable.
|SAS data library||a collection of SAS data sets and other SAS files that are stored and referenced as a unit.|
|SAS data set||a collection of information stored as a unit under the SAS System. Several SAS data sets can be stored in a SAS data library. Unlike external files, a SAS data set is processed and controlled only through the SAS System. See SAS data file and SAS data view for how SAS data sets are implemented in Version 7 of the SAS System.|
|SAS data view||one of the formats of a SAS data set. A SAS data view contains only the descriptor and other information required to retrieve the data values from other SAS files or external files. Both PROC SQL views and SAS/ACCESS views are considered SAS data views. SAS data views are of the member type VIEW.|
|schema item||names and defines the 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. Same as item.
|schema record||an identifiable set of associated schema items treated as a unit in a SYSTEM 2000 database. Same as record.|
|secondary password||a password, other than the master password or DBA password, having restricted SYSTEM 2000 statement usage and specifically assigned update, retrieval, and where-clause authorities for any or all components in a SYSTEM 2000 database.|
|single-user environment||the SYSTEM 2000 execution environment in which you are working with your own copy of SYSTEM 2000 software. Usually, in a single-user environment, you have exclusive access to the database. However, the single-user environment, can be configured so that that all users can query the database. See also Multi-User environment.|
|stored string||one or more SYSTEM 2000 statements stored in a database definition. For example, you can store a SYSTEM 2000 where-clause as a string.|
|U-authority||a code that gives a secondary password the authority to update a SYSTEM 2000 schema item or record; set by the master password holder.|
|variable||a column in a SAS data file. Each SAS variable can have the following attributes: name, 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 that
is named and stored for later use. This file contains no data, but it describes
or defines data stored elsewhere. SAS data views can be created by the ACCESS
and SQL procedures. See also SAS data view.
For example, when a SAS/ACCESS view -- a view descriptor -- is referenced in the SAS PRINT procedure, the view reads data directly from a SYSTEM 2000 database. You can also reference this view in certain SAS procedures to update the database described by a SAS/ACCESS view.
A view defined by the SQL procedure reads data from its underlying SAS data files, other PROC SQL views, or SAS/ACCESS views. Its output table can be a subset or a superset of one or multiple underlying structures. However, in Release 6.06, you cannot reference a PROC SQL view to update its underlying data. ?????
|view descriptor||a SAS/ACCESS file that defines a subset of a database described by an access descriptor. The subset consists of selected items in a given path of one SYSTEM 2000 database with optional selection and ordering criteria. See also access descriptor.|
|W-authority||a code that gives a secondary password the authority to use a SYSTEM 2000 schema item or record for selection criteria in a where-clause.|
|where-clause||a set of one or more user-specified conditions that states the selection criteria for SYSTEM 2000 updates or retrievals.|
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