Glossary
I
identifier
One or more characters used to identify or
name a data element and possibly to indicate certain properties of that data
element. (A)
ILU
Independent logical unit.
import
To copy data from an external file, using
formats such as PC/IXF, DEL, WSF or ASC, into database manager tables.
Contrast with export.
import utility
Transactional utility that inserts
user-supplied record data into a table.
independent logical unit (ILU)
An LU that is able to activate an LU-LU
session without assistance from a system services control point (SSCP). It
does not have an SSCP-LU session. Contrast with dependent logical unit.
index
A set of pointers that are logically
ordered by the values of a key. Indexes provide quick access to data and can
enforce uniqueness on the rows in the table.
index key
The set of columns in a table used to
determine the order of index entries.
index partition
The part of an index that is associated
with a table partition at a given node. An index defined on a table is
implemented by multiple index partitions, one per table partition.
index sargable predicates
Predicates that are applied to index
entries, in index leaf pages, to reduce the number of index entries that
qualify the SQL request. This helps reduce the number of data rows accessed.
indicator variable
A variable used to represent the null
value in an application program. If the value for the selected column is null,
a negative value is placed in the indicator variable.
indoubt transaction
Pertains to a transaction in which one
phase of a two-phase commit completes successfully but the system fails before
a subsequent phase can complete.
initialization fullselect
The first fullselect in a recursive common
table expression that gets the direct children of the initial value from the
source table.
inner join
A join method in which a column that is
not common to all of the tables being joined is dropped from the resultant
table. Contrast with outer join.
inoperative package
A package that cannot be used because one
or more functions that it depends on have been dropped. Such a package must be
explicitly rebound. Contrast with invalid package.
inoperative trigger
A trigger that is no longer usable. A
trigger will be marked inoperative when an object on which it depends is
dropped (or made inoperative) or a privilege on which it depends is revoked.
inoperative view
A view that is no longer usable. A view
will be marked as inoperative when either:
- SELECT privilege on a table or view that the view is dependent on is
revoked from the definer of the view.
- An object on which the view definition is dependent was dropped (or
possibly made inoperative in the case of another view).
insert rule
A condition enforced by the database
manager that must be met before a row can be inserted into a table.
instance
See database manager instance.
intermediate network node
In APPN, a node that is part of a route
between an origin LU (OLU) and a destination LU (DLU) but that neither
contains the OLU or the DLU nor serves as the network server for either the
OLU or DLU.
internal CCD table
A consistent change data table that is a
join of the change data table and the unit-of-work table at the source server.
Internet Protocol (IP)
A protocol used to route data from its
source to its destination in an Internet environment.
Internetwork Packet Exchange** (IPX**)
A connectionless datagram protocol, used
in a NetWare** LAN environment, to transfer data to a remote node. IPX makes a
best-effort attempt to send data packets, but does not guarantee reliable
delivery of the data.
inter-partition parallelism
Refers to the ability to perform multiple
database operations (such as index creation, database load, and SQL queries)
at the same time across multiple partitions of a partitioned database.
Contrast with intra-partition parallelism.
Inter-Process Communication (IPC)
A mechanism of an operating system that
allows processes to communicate with each other.
intra-partition parallelism
Refers to the ability to perform multiple
database operations (such as index creation, database load, SQL queries) at
the same time within a single database partition. Contrast with
inter-partition parallelism.
intra-query parallelism
Processing parts of a single query at the
same time using either intra-partition parallelism, inter-partition
parallelism, or both.
invalid package
A package that becomes invalid when an
object that the package depends on is dropped. (The object is of a type other
than function; for example, index.) Such a package is implicitly rebound upon
invocation. Contrast with inoperative package.
I/O parallelism
See parallel I/O.
IP
Internet Protocol.
IPX**
Internetwork Packet Exchange**.
isolation level
An attribute that defines the degree to
which an application process is isolated from other concurrently executing
application processes.
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