Glossary
This glossary defines terms and abbreviations used in this manual. If you
do not find the term you are looking for, refer to the index or to the Dictionary of Computing, New York: McGraw-Hill, 1994.
A
- access function
- A user-provided function that converts
the data type of text stored in a column to a type that can be processed by DB2 Net Search Extender.
B
- Boolean search
- A search in which one or more search
terms are combined using Boolean operators.
C
- catalog view
- A view of a system table created by DB2 Net Search Extender
Text for administration purposes. A catalog view contains information about
the tables and columns that have been enabled for use by DB2 Net Search Extender Text.
- CCSID
- Coded Character Set Identifier.
- code page
- An assignment of graphic characters and
control function meanings to all code points. For example, assignment of characters
and meanings to 256 code points for an 8-bit code.
- command line processor
- A program called db2text
that:
- Allows you to enter DB2 Net Search Extender commands
- Processes the commands
- Displays the result
- count
- A keyword used to specify the number of levels
(the depth) of terms in the thesaurus that are to be used to expand the search
term for the given relation.
D
- DBCS
- Double-byte character set.
- disable
- To restore a database to its condition
before it was enabled for DB2 Net Search Extender Text by removing the items created during the
enabling process.
- document
- See text document.
- document model
- The definition of the
structure of a document in terms of the sections that it contains. A document
model makes DB2 Net Search Extender aware of the sections within documents when indexing. A document
model lists the markup tags that identify the sections. For each tag you can
specify a descriptive section name for use in queries against that section.
You can specify one or more document models in a document models file.
E
- enable
- To prepare a database for use by DB2 Net Search Extender.
- escape character
- A character indicating that the
subsequent character is not to be interpreted as a masking
character.
- expand
- The action of adding to a search term additional
terms derived from a thesaurus.
F
- format
- The type of a document, such as ASCII, or
HTML.
- free-text search
- A search in which the search term
is expressed as free-form text - a phrase or a sentence describing in
natural language the subject to be searched for.
- function
- See access function.
- fuzzy search
- A search that can find words whose
spelling is similar to that of the search term.
H
- hybrid search
- A combined Boolean
search and free-text search.
I
- index
- To extract significant terms from text, and
store them in a text index.
- index characteristics
- Properties of a text index determining:
- The frequency with which the index is updated
- When the first index update is to occur
L
- log table
- A table created by DB2 Net Search Extender containing information
about which text documents are to be indexed. Triggers are used to store this information in a log table whenever a document
in an enabled text column is added, changed, or deleted.
M
- masking character
- A character used to represent
optional characters at the front, middle, and end of a search term. Masking
characters are normally used for finding variations of a term in a precise
index.
- match
- The occurrence of a search term in a text
document.
P
- periodic indexing
- Indexing at
predetermined time intervals, expressed in terms of the day, hour, and minute,
and the minimum number of documents names that must be listed in the log table for indexing, before indexing can take place.
R
- retrieve
- To find a text document using a search
argument in one of DB2 Net Search Extender's search functions.
S
- SBCS
- Single-byte character set.
- Score
- An absolute value of type DOUBLE between
0 and 1 that indicates how well a document meets the search criteria relative
to the other found documents. The value indicates the number of matches found
in the document in relation to the document's size.
- search argument
- The conditions specified when making
a search, consisting of one or several search terms, and search parameters.
T
- text column
- A column containing text documents.
- text document
- Text of type CHAR, GRAPHIC, VARGRAPHIC,
LONG VARGRAPHIC, DBCLOB, VARCHAR, LONG VARCHAR, or CLOB datatypes, stored
in a DB2 table.
- text index
- A collection of significant terms extracted
from text documents. Each term is associated with the document from which
it was extracted. A significant improvement in search time is achieved by
searching in the index rather than in the documents themselves.
- tracing
- The action of storing information in a
file that can later be used in finding the cause of an error.
- trigger
- A mechanism that automatically adds information
about documents that need to be indexed to a log table whenever a document is added, changed, or deleted from a text column.
U
- UDF
- User-defined function.
- UDT
- User-defined type.
- update frequency
- The frequency
with which a text index is updated, expressed in terms of the day, hour, and
minute, and the minimum number of document names that must be listed in the log table for indexing, before indexing can take place.
- user-defined type (UDT)
- A data type created by
a user of DB2, in contrast to a data type provided by DB2 such as LONG VARCHAR.
- user-defined function (UDF)
- An SQL function created
by a user of DB2, in contrast to an SQL function provided by DB2.
W
- wildcard character
- See masking
character.