CLOB Interface

Table 2-31 describes the CLOB interface that enables the document or stop word from stoplist object to be tokenized to be passed as CLOB from Oracle Text to the stored procedure and for the tokens to be passed as CLOB as well from the stored procedure back to Oracle Text.

The user-defined lexer indexing procedure should use this interface when at least one of the documents in the column to be indexed is larger than 32512 bytes or the corresponding tokens are represented by more than 32512 bytes.

Table 31 CLOB Interface for INDEX_PROCEDURE

Parameter Position Parameter Mode Parameter Datatype Description

1 IN CLOB Document or stop word from stoplist object to be tokenized.

Parameter Position	Parameter Mode	Parameter Datatype	Description
1	`IN`	`CLOB`	Document or stop word from stoplist object to be tokenized.
2	`IN` `OUT`	`CLOB`	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. 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. The `IN` value will always be a truncated `CLOB`.
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 OUT

CLOB

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.

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. The IN value will always be a truncated CLOB.

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.

The first and second parameters are temporary CLOBS. Avoid assigning these CLOB locators to other locator variables. Assigning the formal parameter CLOB locator to another locator variable causes a new copy of the temporary CLOB to be created resulting in a performance hit.