N

name server

A component of the CA IDMS database communications architecture that identifies the location of resources within the network.

native VSAM support

The ability to use CA IDMS/DB to access data from a file defined to VSAM and containing VSAM records. The VSAM files must be defined to CA IDMS/DB by including specific statements in the schema and DMCL DDL. Once defined to CA IDMS/DB, the VSAM files appear to the DBMS as CA IDMS/DB files and can be accessed by CA IDMS/DB applications.

natural collating sequence

A collating sequence in which negative numeric values are sorted lower than positive values. See also standard collating sequence.

navigation

The process of searching the sets stored in a database and of following the member record pointers (next, prior, or owner) to locate specific record occurrences.

navigational database access

A database access method that requires knowledge of the physical structure of the database. Navigational database access allows programmers precise control of the database. See also SQL database access.

navigational DML

1) A data manipulation language that obtains and updates the database one record at a time, using currency and error checking to ensure correct results. 2) Non-SQL DML database and DC/UCF commands.

nested structure

Any data processing structure in which one component exists as a sublevel of another component. See also bill-of-materials structure.

next linkage

In CA IDMS/DB, the type of set linkage in which the owner and members of a set occurrence are linked by next pointers. Next pointers cause the owner to point to the first member, the first member to point to the second member, and so on; the last member points to the owner.

node

A system defined to a DC/UCF communications network.

node name

The logical name of a DC/UCF system.

Non-Interruptable Mode

The Animation Mode in which you do not specify animation stop (interrupt) points. CA ADS Alive steps through dialog animation one line of code at a time, pausing for a specified length of time. The Non-Interruptable Mode causes all CA ADS Alive Animation Runtime Session commands to be inoperative. See also Interruptable Mode.

non-sharable transaction

A transaction initiated by a database session for which transaction sharing is not enabled. A non-sharable transaction cannot be shared by sessions that are peers of the initiating session but can be shared by sessions that are subordinate to the initiating session. See also sharable transaction, peer session, subordinate session.

non-SQL defined schema

A schema defined with non-SQL DDL statements.

non-terminating task data transfer

A means of data transfer between program storage and a terminal that allows a front-end application (for example, a CICS user task) to wait for information from a CA IDMS UCF back end without terminating. See also terminating task data transfer.

nonoperative status

In CA ADS, the status of a dialog when control has passed from that dialog to another dialog with the TRANSFER or RETURN command (that is, when the dialog is no longer part of the application thread).

nonterminal task

A task that is not initiated from a terminal. For example, a task that DC/UCF initiates automatically at startup or shutdown.

NOREADY

In CA ADS, an option of the READY AREA compiler directive that indicates that a dialog will not use the area and that the CA ADS runtime system should not ready it when a database transaction begins.

normalization

The analysis of data structures based on a set of rules. The rules eliminate redundancy and ensure unique identifiers. Under this approach, data can be normalized to varying degrees (first normal form, second normal form, third normal form). Third normal form is typically used to design stable data structures. Normalization is part of the database design process.

notify lock

A special form of the longterm lock established by using the LONGTERM NOTIFY option of the KEEP DML command. Notify locks monitor database activity for the record that is current of record type, set, or area. See also locking, longterm lock, record lock.

nucleus

The group of modules that perform DC/UCF system functions, such as program loading and storage management. Nucleus modules are stored in the appropriate program and reentrant pools.

nucleus map

A table listing the name and address of each module in the DC/UCF nucleus.

null PDE

A generic program definition element that is set aside during system startup for later use. You allocate null PDEs to a system when you want DC/UCF to define programs automatically. Null PDEs are defined during system generation. See also automatic program definition.

null SELECT clause

In LRF, a SELECT clause without any path descriptors. This clause identifies a path that LRF can match with any logical-record request.

null value

A construct that denotes the absence of a value and is not the same as spaces or numeric zeros, which are actual values. In an SQL-defined database, a column, regardless of data type, can contain a null value unless the column definition specifically disallows them.

null-lock mode

A special type of logical lock which is placed on a record to signify a notify lock and on an area to signify transient retrieval access. Null-locks provide no protection against concurrent access. See also share lock mode, exclusive lock mode.