SAS/ACCESS Interface to IMS-DL/I Software

Glossary

ACB	See Application Control Block (ACB).
ACBLIB	the data set containing the Application Control Blocks.
access descriptor	a SAS/ACCESS file that describes data to the SAS System that is managed by an external software vendor's DBMS product. You use an access descriptor as a master file to create view descriptors. See also view descriptor.
Application Control Block (ACB)	a DL/I control block that contains the combined information from the Database Descriptions (DBDs) and Program Specification Blocks (PSBs).
attach parameter list	a set of parameters passed to DL/I when the IMS-DL/I engine or the IMS-DL/I DATA step interface is executed in a DL/I environment. The parameters vary for each region type. Most parameters can be modified with the SAS system options specified for the SAS/ACCESS interface for IMS-DL/I.
batch mode	a method of executing SAS programs in which you prepare a file containing SAS statements and any necessary operating system commands, and submit the program to the computer's batch queue. While the program executes, control of the SAS System returns to your terminal or workstation where you can perform other tasks. Batch mode is sometimes referred to as running in the background. The job output can be written to files or printed on an output device.
batch region	a DL/I processing environment for accessing DL/I databases. Database data sets must be allocated to this region. A batch region is supervised by the DL/I batch control program.
BMP region	an abbreviation for Batch Message Processing region. The BMP region is a DL/I processing environment in IMS/ESA DB/DC subsystems and in CICS for running programs that access active online DL/I databases and message queues, as well as non-DL/I data sets. Database data sets are allocated to an online control region, not to the BMP region.
browsing data	the process of viewing the observations in a file. Depending on how the file is accessed, observations may be viewed one at a time or as a group in a tabular format. You cannot update data that you are browsing.
call (DL/I)	a request made by the IMS-DL/I engine to DL/I or by the IMS-DL/I DATA step interface to access one or more segments of a database or message queue, or to perform some system function.
checkpoint	the result of a CHKP call. A checkpoint establishes a synchronization point in the execution of the program. A synchronization point is used by DL/I backout services to determine which updates to back out (cancel) in the event of an abend or system crash. The program must be restarted at the synchronization point.
checkpoint ID	an 8-byte value written to the DL/I log record to identify the program checkpoint.
child	a segment in a DL/I database that is the direct dependent of another segment, which is called its parent. The data in a dependent segment rely on the parent segment and all higher segments for complete identification and qualification.
command code	a special indicator used in a Segment Search Argument (SSA) to modify the type of call being issued. The most commonly used command code is the D code, which is used to issue a path call.
control block	a storage area created by the system containing information for controlling system operations. The control block is often loaded from a control block library; for example, Database Descriptions (DBDs) may be stored in DBDLIBs.
DATA step	a group of statements in a SAS program that begins with a DATA statement and ends with either a RUN statement, another DATA statement, a PROC statement, the end of the job, or the semicolon that immediately follows instream data lines. The DATA step enables you to read raw data or other SAS data sets and use programming logic to create a SAS data set, write a report, or write to an external file.
DATA step view	a DATA step program that generates a SAS data view. Like other SAS data views, a DATA step view contains a definition of data stored elsewhere; it does not contain the physical data. DATA step views can only function as input data sets in SAS System releases beyond Release 6.08. An input DATA step view is generated from a DATA step program. 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 this view's underlying data.
data type	an attribute of every item in a database. The data type tells the operating system how much physical storage to set aside for the item and the type of data the item will contain. It is similar to the type attribute of SAS variables.
data value	an element in a collection of data values that are organized and presented to the SAS System in a rectangular structure of columns and rows. A data value represents the intersection of a row and a column.
database	an organized collection of related data. In IMS-DL/I, a database is a collection of interrelated data elements that are organized according to a particular data model that can be processed by multiple applications.
Database Administrator (DBA)	the person responsible for developing and maintaining database management systems at a computer site.
Database Description (DBD)	a DL/I control block that defines the hierarchical data structure and the physical characteristics of a database to DL/I.
database management system (DBMS)	an integrated software package that enables you to create and manipulate data in the form of databases. See also relational database management system.
Database Recovery Control (DBRC)	an IMS facility that controls restoration of databases after a system failure. DBRC also supports data sharing among IMS/ESA subsystems.
DBB region	a DL/I batch processing environment for running programs that can access DL/I databases as well as non-DL/I data sets. In a DBB region, DL/I accesses the ACBLIB for control block information.
DBD	See Database Description (DBD).
DBDGEN	the utility procedure that generates a Database Description (DBD).
DBDLIB	a data set that contains the Database Descriptions (DBDs).
DBRC	Database Recovery Control (DBRC).
dependent segment	a segment that has a parent segment. The data in a dependent segment rely on the parent segment and all higher segments for complete identification and qualification.
DL/I	an abbreviation for Data Language/I. DL/I is IBM's database language for IMS/ESA, CICS/OS/ESA, CICS/DOS/VS, and DL/I DOS/VS systems.
DLI region	a DL/I batch processing environment for running programs that can access DL/I databases, as well as non-DL/I data sets. No access to message queues is possible. In a DLI region, DL/I accesses the DBDLIB and PSBLIB for control block information.
editing data	the process of viewing a file with the ability to change its data. You might see the data one observation at a time or in a tabular format.
engine	a part of the SAS System that reads from or writes to a file. Each engine allows the SAS System to access files with a particular format. There are several types of engines. See also interface view engine.
feedback data	the data returned from IMS to the IMS-DL/I engine (usually in the PCB mask) after a DL/I call has been issued.
field	the smallest unit of data storage in an IMS-DL/I database.
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.
format	an instruction the SAS System uses to display or write each value of a variable. Some formats are supplied by SAS software. Other formats can be written by the user with the FORMAT procedure in base SAS software or with SAS/TOOLKIT software.
Get call	a DL/I call that retrieves one or more segments so that the contents of the segments can be processed or mapped by the IMS-DL/I engine.
hierarchical database	a database organized as a tree structure of segments. A DL/I database has a hierarchical data structure.
hierarchical sequence	the standard processing sequence for segments of a database record; the sequence is basically top-to-bottom, front-to-back, and left-to-right. When segments in a DL/I database are retrieved one after the other in sequential fashion, DL/I presents them in hierarchical sequence.
hierarchical structure	an arrangement of data in which records occur at distinct levels with different types of information at each level. Records are related to other records as ancestors, descendants, siblings, and so on.
IMS/ESA	an abbreviation for Information Management System/Enterprise System Architecture. IMS/ESA is an IBM database management system that uses the DL/I language.
IMS/ESA Resource Lock Manager (IRLM)	a facility for ensuring database integrity among multiple DL/I subsystems.
index	in SAS Software, a part of a SAS data file that stores both the values of a variable (in a SAS data file) and a set of directions that enable the SAS System, under certain circumstances, to locate observations in a data file more quickly and efficiently. Indexing variables usually makes data set processing faster, although the SAS System determines the most efficient way to process data maintained by the SAS System.
informat	an instruction the SAS System uses to read raw data values to create variable values. Some informats are supplied by SAS software. Other informats can be written by the user with the FORMAT procedure in base SAS software or with SAS/TOOLKIT software.
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. The SAS System processes each line immediately after you press the ENTER key. Procedure output and informative messages are returned directly to the display monitor.
interface view engine	a SAS System engine that retrieves data directly from files formatted by other software vendors and presents the data to the SAS System in the form of a SAS data set. Interface view engines are transparent to the user and are not specified in the LIBNAME statement.
I/O area	a data structure into which a retrieved segment is placed or from which a segment being written is taken.
I/O PCB	an abbreviation for Input/Output Program Communication Block. The I/O PCB communicates information on non-database access requests.
IRLM	See IMS/ESA Resource Lock Manager (IRLM).
key field	a field that identifies and provides access to an occurrence of a segment. A key field is also called a sequence field.
libref	(1) the name temporarily associated with a SAS data library. You assign a libref with a LIBNAME statement or with operating-system control language. (2) the first part of a multilevel SAS filename indicating the SAS data library in which the file is stored. For example, in the name SASUSER.ACCOUNTS, the name SASUSER is the libref.
logical database	a collection of database segments from one or more physical databases. It enables the SAS/ACCESS IMS-DL/I interface to view a database structure that is different from the physical structure.
member	a file in a SAS data library.
member name	a name given to a file in a SAS data library. A member name can reference a SAS data set, catalog, access descriptor, or stored program.
member type	a name assigned by the SAS System that identifies the type of information stored in a SAS 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 prints a missing numeric value as a single period (.) and a missing character value as a blank space.
noninteractive mode	a method of running SAS programs in which you prepare a file of SAS statements and submit the program to the operating system. The program runs immediately and occupies your current session.
observation	the horizontal component of a SAS data set. An observation 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. An observation is analogous to a record in an IMS database. Unlike rows in a DBMS table or file, observations in a SAS data file have an inherent order.
online access region	a DL/I processing environment for running batch-type programs that can access active online DL/I databases. In the SAS/ACCESS interface to IMS-DL/I, the only online access region type supported is BMP region.
online control region	a DL/I region that controls databases and terminals and schedules activities using these resources for online processing.
parent	a segment in a DL/I database that has one or more dependent segments, which are called its children. The data in a dependent segment rely on the parent segment and all higher segments for complete identification and qualification.
path	a single route through a database following the hierarchical sequence of segments from a higher-level segment to a lower-level segment.
path call	a DL/I call to a database that returns multiple segments from the hierarchical path.
PCB	See Program Communication Block (PCB).
PCB mask	a data structure to which DL/I returns information about the DL/I calls issued by an application.
physical database	a collection of database segments in a specified hierarchical structure. These segments are organized according to a particular DL/I access method.
PROC SQL view	a SAS data view defined by the SQL procedure that reads data from its underlying SAS data files, other PROC SQL views, SAS/ACCESS views, or DATA step views. Its output table can be a subset or a superset of one or multiple underlying structures. In the current release of the SAS System, you cannot reference a PROC SQL view to update its underlying data.
PROC step	a group of SAS statements that call and execute a procedure, usually with a SAS data set as input.
Program Communication Block (PCB)	a DL/I control block that defines a message queue or the part of a database that can be accessed by the IMS-DL/I engine or by the IMS-DL/I DATA step interface. A PCB is part of a Program Specification Block (PSB).
Program Specification Block (PSB)	a DL/I control block that defines the DL/I resources used by the IMS-DL/I engine or by the IMS-DL/I DATA step interface. Each database used by the IMS-DL/I engine is defined by a separate Program Communication Block (PCB) within the PSB.
program view	the part of a database that can be accessed by the IMS-DL/I engine or by the IMS-DL/I DATA step interface. The program view is established by the Program Communication Block (PCB).
PSB	See Program Specification Block (PSB).
PSBGEN	the utility procedure that generates a Program Specification Block (PSB).
PSBLIB	a data set that contains the Program Specification Blocks (PSBs).
qualified call	a DL/I call that specifies at least one Segment Search Argument (SSA).
qualified SSA	a Segment Search Argument that contains one or more qualification statements to specify search criteria for locating particular segment occurrences.
random access	the access mode used by the IMS-DL/I engine or by the IMS-DL/I DATA step interface when a WHERE statement is specified from which the engine can generate qualified Segment Search Arguments. In the SAS/ACCESS interface to IMS-DL/I, the distinction between sequential and random access differs from that of some other programming languages.
read integrity	the sharing of database access so that two programs cannot access a record simultaneously if one of the programs intends to update the record.
region type	the kind of DL/I processing environment. The IMS-DL/I engine uses two categories of region types: batch regions (DLI or DBB) and online access regions (BMP).
relational database management system	a database management system that organizes and accesses data according to relationships between data items. The main characteristic of a relational database management system is the two-dimensional table.
restart	the process of resuming an interrupted program without repeating completed transactions.
restricted option	a SAS option that has been installed at your site so that its default setting cannot be overridden by the applications programmers.
return code	a code passed to the operating system that reports the results of executing a command or job step.
root segment	the highest-level segment in a database.
SAS data file	a SAS data set that contains both the data values and the descriptor information.
SAS data library	a collection of one or more SAS files that are recognized by the SAS System. Each file is a member of the library. See also libref and member.
SAS data set	a collection of information stored as a unit under the SAS System. A SAS data set is arranged in a rectangular, two-dimensional format. Each item in a SAS data set is called a data value. Data values in a row comprise an observation, and those in a column comprise a variable. See also SAS data file and SAS data view.
SAS data view	a SAS data set in which the descriptor information and observations are obtained from other files. SAS data views store only the information required to retrieve data values or descriptor information.
SAS/ACCESS views	See SAS data view and view descriptor.
search field	a field defined to DL/I in the Database Description (DBD) that can be used to search for particular segments. A search field does not provide unique identification of the segment.
segment	in a DL/I database, a grouping of related items of data in a database structure. The segment is the unit of data that can be accessed by the IMS-DL/I engine or by the IMS-DL/I DATA step interface.
segment level	the relative distance of a given segment from the root segment along the hierarchical path. This is usually represented numerically, with the root segment at level 1 and its immediate dependents at level 2.
segment occurrence	in a DL/I database, a specific instance in a set of segments of one type.
Segment Search Argument (SSA)	the formatted search criteria passed to DL/I to identify a particular segment or group of segments to be processed. Multiple SSAs may be specified on one DL/I call.
segment type	in a DL/I database, a category of related data elements. There may be multiple segment occurrences for a given segment type.
sensitive segment	a segment in a DL/I database that the IMS-DL/I engine or the IMS-DL/I DATA step interface can access. A segment is defined as sensitive for a given program in the Program Specification Block (PSB).
sequence field	See key field.
sequential access	the default access mode used by the IMS-DL/I engine to retrieve all segments down one path of a database. Sequential access is a method of file access in which the records are read or written one after the other from the beginning of the file to the end. In the SAS/ACCESS interface to IMS-DL/I, the distinction between sequential and random access differs somewhat from that of other programming languages.
siblings	segments that share a common parent segment.
SSA	See Segment Search Argument (SSA).
status code	a 2-byte indicator field returned to an application program by DL/I to indicate the relative success of an attempted call.
Structured Query Language (SQL)	the standardized, high-level query language used in relational database management systems to create and manipulate database management system objects. The SAS System implements SQL through the SQL procedure.
subsystem	a complete DL/I configuration, including the DL/I region controller and service modules, the DL/I databases.
synchronization point	a commitment of completed updates and a time at which all DL/I resources held since the last synchronization point are released. Synchronization points are established explicitly by CHKP calls, which the IMS-DL/I engine issues (by default) at the beginning and end of update processing. Synchronization points can be used to resume processing of an interrupted job.
twins	segments that represent multiple occurrences of the same segment type under a single parent.
undefined field	a field that is not defined to DL/I in a Database Description (DBD). An undefined field is neither a sequence field nor a search field. A segment cannot be accessed by specifying this field to DL/I.
unqualified call	a DL/I call that contains no Segment Search Argument (SSA).
unqualified SSA	a Segment Search Argument that specifies a segment type and, optionally, a command code.
Update call	a DL/I call that signals the intent to alter (modify, delete, or add) information in the database.
update integrity	the sharing of database access so that two programs cannot access a record simultaneously if both of the programs intend to update the record.
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 descriptor	a SAS/ACCESS file that defines all or a subset of interface product data described by an access descriptor. The access descriptor describes the data in a single product table or view, when views are allowed in the product. See also access descriptor.
windowing procedure	a procedure that uses windows and menus to accomplish a SAS System task. For example, ACCESS, FSVIEW, and DBLOAD are windowing procedures.

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