Oracle如何对CLOB行字段执行全文检索

create table products( 
productid number(10) not null ,
name varchar2(255) ,
description CLOB) ;

SELECT productid, name FROM products 
WHERE dbms_lob.instr(products.description,'some text',1,1) > 0;

APPEND procedure Appends the contents of 
the source LOB to the destination LOB. 

CLOSE procedure Closes a previously 
opened internal or external LOB. 

COMPARE function Compares two entire 
LOBs or parts of two LOBs. 

COPY procedure Copies all, or part, 
of the source LOB to the destination LOB. 

CREATETEMPORARY procedure Creates a temporary 
BLOB or CLOB and its corresponding index 
in the user's default temporary tablespace. 

ERASE procedure Erases all or part of a LOB. 

FILECLOSE procedure Closes the file. 

FILECLOSEALL procedure Closes all previously opened files. 

FILEEXISTS function Checks if 
the file exists on the server. 

FILEGETNAME procedure Gets the 
directory alias and file name. 

FILEISOPEN function Checks if the 
file was opened using the input BFILE locators. 

FILEOPEN procedure Opens a file. 

FREETEMPORARY procedure Frees the 
temporary BLOB or CLOB in the user's default temporary tablespace. 

GETCHUNKSIZE function Returns the amount 
of space used in the LOB chunk to store the LOB value.

GETLENGTH function Gets the length of the LOB value. 

INSTR function Returns the matching position 
of the nth occurrence of the pattern in the LOB. 

ISOPEN function Checks to see if the LOB 
was already opened using the input locator. 

ISTEMPORARY function Checks if the locator 
is pointing to a temporary LOB. 

LOADFROMFILE procedure Loads 
BFILE data into an internal LOB. 

OPEN procedure Opens a LOB 
(internal, external, or temporary) in the indicated mode. 

READ procedure Reads data from 
the LOB starting at the specified offset.

SUBSTR function Returns part of the 
LOB value starting at the specified offset. 

TRIM procedure Trims the LOB 
value to the specified shorter length. 

WRITE procedure Writes data 
to the LOB from a specified offset. 

WRITEAPPEND procedure Writes a buffer to the end of a LOB.