it says:
BLOB and TEXT columns also can be indexed, but a prefix length must be
given.
Prefix lengths are given in characters for non-binary string types and in
bytes for binary string types. That is, index entries consist of the first
length characters of each column value for CHAR, VARCHAR, and TEXT columns,
and the first length bytes of each column value for BINARY, VARBINARY, and
BLOB columns.
###
So I'm not sure if it is really useful to index these columns. Is there
ever a lookup done on object contents?
I also found this item:
http://www.idevelopment.info/data/Oracle/DBA_tips/LOBs/LOBS_2.shtml
which show how to create a table with a LOB (large object either BLOB or
CLOB) but it looks like you have to specify a TABLESPACE to hold the
BLOB/CLOB index.
Does anyone have a sense of whether this is worth the effort to index XWiki
CLOB's ?
CREATE TABLE test_lobtable (
id NUMBER
, xml_file CLOB
, image BLOB
, log_file BFILE
)
LOB (xml_file)
STORE AS xml_file_lob_seg (
TABLESPACE lob_data
CHUNK 4096
CACHE
STORAGE (MINEXTENTS 2)
INDEX xml_file_lob_idx (
TABLESPACE lob_index
STORAGE (MAXEXTENTS UNLIMITED)
)
)
---snip---
Here is Hibernate reference to using Oracle CLOB :
http://www.hibernate.org/56.html
but it mentions nothing about indexes.
--
View this message in context:
http://www.nabble.com/Oracle-Database-Index-tp16945142p16974580.html
Sent from the XWiki- Dev mailing list archive at
Nabble.com.