VARCHAR2 Interface

Table 2-30 describes the interface that enables the document or stop word from stoplist object to be tokenized to be passed as VARCHAR2 from Oracle Text to the stored procedure and for the tokens to be passed as VARCHAR2 as well from the stored procedure back to Oracle Text.

Your user-defined lexer indexing procedure should use this interface when all documents in the column to be indexed are smaller than or equal to 32512 bytes and the tokens can be represented by less than or equal to 32512 bytes. In this case the CLOB interface given in Table 2-31 can also be used, although the VARCHAR2 interface will generally perform faster than the CLOB interface.

This procedure must be defined with the following parameters:

Table 30 VARCHAR2 Interface for INDEX_PROCEDURES

Parameter Position Parameter Mode Parameter Datatype Description

Parameter Position	Parameter Mode	Parameter Datatype	Description
1	`IN`	`VARCHAR2`	Document or stop word from stoplist object to be tokenized. If the document is larger than 32512 bytes then Oracle Text will report a document level indexing error.
2	`IN` `OUT`	`VARCHAR2`	Tokens encoded as XML. If the document contains no tokens, then either NULL must be returned or the tokens element in the XML document returned must contain no child elements. Byte length of the data must be less than or equal to 32512. To improve performance, use the `NOCOPY` hint when declaring this parameter. This passes the data by reference, rather than passing data by value. The XML document returned by this procedure should not include unnecessary whitespace characters (typically used to improve readability). This reduces the size of the XML document which in turn minimizes the transfer time. To improve performance, index_procedure should not validate the XML document with the corresponding XML schema at run-time. Note that this parameter is `IN` `OUT` for performance purposes. The stored procedure has no need to use the `IN` value.
3	`IN`	`BOOLEAN`	Oracle Text sets this parameter to `TRUE` when Oracle Text needs the character offset and character length of the tokens as found in the document being tokenized. Oracle Text sets this parameter to `FALSE` when Text is not interested in the character offset and character length of the tokens as found in the document being tokenized. This implies that the XML attributes off and len must not be used.

IN

VARCHAR2

Document or stop word from stoplist object to be tokenized.

If the document is larger than 32512 bytes then Oracle Text will report a document level indexing error.

IN OUT

VARCHAR2

Tokens encoded as XML.

If the document contains no tokens, then either NULL must be returned or the tokens element in the XML document returned must contain no child elements.

Byte length of the data must be less than or equal to 32512.

To improve performance, use the NOCOPY hint when declaring this parameter. This passes the data by reference, rather than passing data by value.

The XML document returned by this procedure should not include unnecessary whitespace characters (typically used to improve readability). This reduces the size of the XML document which in turn minimizes the transfer time.

To improve performance, index_procedure should not validate the XML document with the corresponding XML schema at run-time.

Note that this parameter is IN OUT for performance purposes. The stored procedure has no need to use the IN value.

IN

BOOLEAN

Oracle Text sets this parameter to TRUE when Oracle Text needs the character offset and character length of the tokens as found in the document being tokenized.

Oracle Text sets this parameter to FALSE when Text is not interested in the character offset and character length of the tokens as found in the document being tokenized. This implies that the XML attributes off and len must not be used.