CTX_THES Result Tables and Data Types

The CTX_THES expansion functions such as BT, NT, and SYN can return the expansions in a table of type EXP_TAB. You optionally specify the name of your table with the restab argument.

EXP_TAB Table Type

The EXP_TAB table type is a table of rows of type EXP_REC.

The EXP_REC and EXP_TAB types are defined as follows in the CTXSYS schema:

type exp_rec is record (
    xrel varchar2(12),
    xlevel number,
    xphrase varchar2(256)
);

type exp_tab is table of exp_rec index by binary_integer;

When you call a thesaurus expansion function and specify restab, the system returns the expansion as an EXP_TAB table. Each row in this table is of type EXP_REC and represents a word or phrase in the expansion. The following table describes the fields in EXP_REC:

EXP_REC Field	Description
xrel	The xrel field contains the relation of the term to the input term (e.g. 'SYN', 'PT', 'RT', etc.). The xrel value is PHRASE when the input term appears in the expansion. For translations, the xrel value is the language.
xlevel	The xlevel field is the level of the relation. This is used mainly when xrel is a hierarchical relation (BT*/NT*). The xlevel field is 0 when xrel is PHRASE. The xlevel field is 2 for translations of synonyms under TRSYN. The xlevel field is 1 for operators that are not hierarchical, such as PT and RT.
xphrase	The xphrase is the related term. This includes a qualifier in parentheses, if one exists for the related term. Compound terms are not de-compounded.