To index a column externally

i want to improve the efficiency of my query, therefore i want to create an external index. plz can anybody help me how to index an existing table.
thanks

Yes, or perhaps most tables are index-organized and "external" means a standalone index. Obviously Oracle do not use any term like this in their documentation. For one thing there are already External Tables, and it would be confusing if there were also External Indexes that were unrelated.

Similar Messages

How to Index a Lacie External Ethernet Drive

I cannot seem to get Spotlight to (a) recognize and (b) index a Lacie external Ethernet Drive I run.
Can anyone advise how I can get both, please?
GWJ
Melbourne, Australia

In contrast to the pre-Tiger "Find" command, Spotlight can't search networked drives. I recommend downloading Easyfind at http://www.versiontracker.com/dyn/moreinfo/macosx/11706 and installing it. Easyfind isn't the very fastest utility but it performs thorough searches and fills this Spotlight design shortcoming well enough.

Indexing multiple columns in multiple tables

I have a multiple tables in which I want to search. I need to do text search that supports fuzzy logic for which I've currently set up a context index using the user_datastore. I also need to search columns such as numbers/dates/timestamps which from what I understand is not supported with the context search. I'm looking at setting up a second index of type ctxcat for this purpose - but I will need to index multiple columns in multiple tables. Is this possible?
Can someone advise on the best way to create indexes and search when a table schema such as the following exists. I've tried to keep it simple by just giving a few example columns and tables.
Order Table
- Has columns related to the order details - order name (varchar2), description (varchar2), date order placed (timestamp), date order completed (date), order amount (number), customer Id
Customer Table
- Has columns related to the customer information - customer name, address, city, state, telephone etc (all varchar2 fields)
Items Table
- Has details about the items being ordered - item name (varchar2), item description (varchar2), cost (number) etc
Order-Item Table
- Table that maps an order to the items in that order - orderId, itemId, quantity
Comments Table
- Logs any comments with the customer - comment description (varchar2), call type (varchar2), comment date (timestamp)
Currently with the Context index, I have it set up so I can search all text columns in all tables for a search term. This works fine.
I now need to be able to do more advanced searches, where I can search for a specific text in all orders as well as orders created after a certain date or orders above a certain amount or orders with a item quantity purchase of more that 10. The text has to be searched across the all text columns in all tables. How can I achieve this with Oracle Text?

There was a similar discussion with various ideas that may help you here:
How can I make CONTAINS query work for a date range

Do I need to create indexes on column name?

Following queries have been shown as bad sql :
select * from t1 where name = 'FUNCTION'
Count=     7     Avg Time=13     Min Time=0     Max Time=47
select * from t2 where name = 'USER_TYPE'
Count=2     Avg Time=85     Min Time=0     Max Time=156
select * from t3 where name = 'TEMPLATE'
Count=7     Avg Time=19     Min Time=0     Max Time=32
All these tables have less than 20 records and static tables.
Do I need to create indexes on column name?

A FTS even on very small tables can require more latches than accessing via an index. Also, a table access requires the segment header and data block to be accessed (2) whereas an index on a small index only requires access to the index root block and table block (2).
True, it's unlikely to make much of a difference in most environments but if the table is really heavily accessed, indexing even very small tables can help to reduce the related latch overheads.
Most of these small tables have PKs and are accessed via the PK so associated indexes usually exist anyways.
Cheers
Richard Foote
http://richardfoote.wordpress.com/

Querying an indexed database column. How?

Hi there,
I am pretty good at CF and okay at SQL.
Over the years I have been informed that when using the same column in a database multiple times to do look-ups....e.g. a primary key field....that it would be best to "index" this column to improve speed.
However, I'm not fully sure what or how to index a database column. I have a few questions:
Is it something to do in MySQL directly? Or can it be done programmatically with CF?
Does it really speed things up a lot?
How is new data entered affected? Does that new data get included into the index?
Does my cfquery syntax have to be any different than is normal?
Any help or advice would be great.
I'm using CF8 and MySQL5 (query browser tools etc)
Thanks,
Mikey.

Indexing is a database topic. As databases can be controled by SQL commands it would most likely be possible to do so inside of a <cfquery...> block, but I would only do that in rare circumstances.
Indexing a table will almost always speed up frequently used database columns. But when, how and why one would index a database column is a big topic on which entire papers, books and college classes have been developed around. I would start with some reading of you database documentation an then branch out onto the internet. You will find much written and should be able to educate yourself easily.

Indexing multiple columns of multiple tables

Hi,
I'm trying to index multiple columns of multiple tables.
As I have seen, the way to do this is using User_Datastore.
have the tables to share a (foreign)key? My tables have only 2 or 3 similar columns(description, tagnr...)
I want to get the different tagnr belonging to the same description etc.
Can I do this?
Has anyone a Samplecode indexing multiple tables?
Any suggestion would be helpful.
Arsineh

A USER_DATASTORE works like this:
create table A
( id number primary key,
textA varchar2(100));
create table B
( id number primary key,
textB varchar2(100));
procedure foo (rid in rowid, v_document in out varchar2)
v_textA varchar2(2000);
v_idA number;
v_textB varchar2(2000);
begin
select id, textA
into v_idA, v_textA
from A
where rowid = rid;
select textB
into v_textB
from B
where id = v_idA;
v_document := textA | | ' ' | | textB;
end;
create preferences for USER_DATASTORE
create index ...
on table A ( text) ...
you also can build on table B
This depends where you want the
trigger to be build to sync the
documents.
null

To index data in external hard drives

I'm using Time Capsule 500GB and Seagate external hard. My iMac and these two hard drives are connected wirelessly. I want to index data in those drives by using Spotlight but I can only index information in my iMac's internal hard. What should I do to index data in external hard drives?

I resolved this problem. Just go to Time Capsule in Finder and search in the upper right corner of Finder! It was more easier than I expected.
Message was edited by: JesseKimjd

Index Key Column Order

I've several queries running on a table (for fetching data), to improve the performance of these queries, we've an Index in place, however, the query optimizer suggests upto 94% cost reduction possibility because of the order of the Index key columns in
40% of the queries.
I know that if I create an Index that matches the order of columns, the result will be better. However, I would like to know is there a possibility of changing order of columns in query itself so that it can use the existing Index? (I tried it but didn't
make any difference).
Also, I want to know how does SQL Server decides a key column order for any query?

Reordering the predicates in your query will not help.
If your query has exact matches on all columns in the index, then the order of the columns in the index key doesn't matter.
For example:
CREATE TABLE t
(col1 char(5)
,col2 char(5)
,description varchar(200)
CREATE INDEX ix ON t (col1, col2)
SELECT description
FROM t
WHERE col1 = 'abc'
AND col2 = 'def'
However, if not all index key columns are filtered, or they are not filtered with equality, then the order does matter.
For example:
SELECT description
FROM t
WHERE col1 LIKE 'a%'
AND col2 = 'def'
In the query above, an index on (col2, col1) is more effective than an index on (col1, col2). If col1 is the leading column, the first match (and every next match) of "col2 = 'def'" has to be scanned within the results of "col1 LIKE 'a%'".
If col2 is the leading column, then no col2 keys with the unmatched values have to be skipped. In other words, fewer keys have to be scanned.
Maybe your query selects a range of values of the index's leading column...
Gert-Jan

How to index a column in an interval partitioned table

Hi -
I see that domain indexes are not allowed on a table which has interval partitioning on it.
Given this limitation, is there any way to improve performance on wildcard searches (like '%condition%';) on a VARCHAR(2) column in a table which has interval partitioning?
Or are we SOL if we want to do this?
Thanks for any advice or experience in this area.
LJ

There's no real good way to make non-domain-indexed text queries fast. If there was, the Text forum wouldn't be the lively place it is today!
But SOL? No, I wouldn't call you SOL... There are always ways to do stuff, just depends on how important it is to you, how much space/time/maintenance you're willing to do to make things work.
For example, create a non-interval-partitioned materialized view of your target table/column and use a domain index on that.
What constraints or options do you have (or think you have) in order to make this work?

Indexing Multiple columns Doesn't work

Here's some help for those of you struggling
with the interMedia sample code for:
"Faster Multi-column Text Searches"
Basically, after you have run the code
cdstore.sql as CTXSYS and granted CTXAPP
to whoever, you are now in a position to
create your concatenated datastore.
Once you have created your datastore, you
create your index, specifying a single
column and the datastore. Your queries to
this index will 'magically' search the full
list of columns in the datastore, even though
you only specify a single column in the
contains part of your query. V.Cool :)
This work for a while until (like I did) you
start to change some of your indexes. Then
when you run a simple query and you get no
rows back AT ALL. This is because your new
index hasn't created properly due to a bug.
You can check this out with the query:
select err_text from ctx_user_index_errors;
If your index is corrupt, you should see:
DRG-50857: oracle error in drsinopen
DRG-50858: OCI error: OCI_INVALID_HANDLE
This is due to the fact that a create
index statement will work only ONCE
in a given session. This is Bug #881851
You can patch this bug, or use 8.1.6 instead.
The current workaround, is to reconnect to
the database and recreate the index.
(OK,so it's a misleading title, since it
actually does work, but I found this rather
puzzling and it's not easy to find in the
documentation)
Adeeva.

Here's some help for those of you struggling
with the interMedia sample code for:
"Faster Multi-column Text Searches"
Basically, after you have run the code
cdstore.sql as CTXSYS and granted CTXAPP
to whoever, you are now in a position to
create your concatenated datastore.
Once you have created your datastore, you
create your index, specifying a single
column and the datastore. Your queries to
this index will 'magically' search the full
list of columns in the datastore, even though
you only specify a single column in the
contains part of your query. V.Cool :)
This work for a while until (like I did) you
start to change some of your indexes. Then
when you run a simple query and you get no
rows back AT ALL. This is because your new
index hasn't created properly due to a bug.
You can check this out with the query:
select err_text from ctx_user_index_errors;
If your index is corrupt, you should see:
DRG-50857: oracle error in drsinopen
DRG-50858: OCI error: OCI_INVALID_HANDLE
This is due to the fact that a create
index statement will work only ONCE
in a given session. This is Bug #881851
You can patch this bug, or use 8.1.6 instead.
The current workaround, is to reconnect to
the database and recreate the index.
(OK,so it's a misleading title, since it
actually does work, but I found this rather
puzzling and it's not easy to find in the
documentation)
Adeeva.

Time Machine index failures and external drives

Greetings,
I have been running into a number of failures with Time Machine on an Intel Core i7 iMac running Mac OS X 10.6.4. The external hard drive is an iOmega "eGo" 2 TB desktop drive connected with USB 2.0. I have used this kind of hard drive before for TIme Machine successfully, on this machine which has as far as I know always run Snow Leopard.
Unfortunately, I cannot put a date or event to when these Time Machine errors began (whether coincident with an OS upgrade or what); the iMac belongs to my research group, and is located in a meeting room where it is used by several people. I'd estimate the TM failures began maybe 3 months ago, after the drive and Time Machine having worked fine for several months before then.
I've already used Disk Utility to repair and/or re-format (remake single partition) the external drive, and checked the iMac's HD for errors. The external is a brand-new drive; I just recently exchanged the previous same-model drive for a replacement, since the previous one failed some kind of diagnostics they performed back at the shop (I don't know what the problem was, there). The first eGo drive was the one that worked for a while with Time Machine. Since I replaced it with a new one, TM has never successfully completed a back-up.
Time Machine's error message is the usual "The backup was not performed because an error occurred while copying files to the backup disk" along with the "The problem may be temporary. Try again later to back up. If the problem persists, use Disk Utility to repair your backup disk." that comes up when I click for more info in the control panel. Below, I've also copied typical outputs from "Time Machine Buddy" and from "system.log" read in Console.
I've tried working through some of the suggested actions at http://web.me.com/pondini/Time_Machine/ (specifically: "full reset," item A4; suggestions at the bottom of D4; and C3), with no luck so far. I also tried using a different external drive (an OWC Mercury Elite Pro 2TB), and tried it connected either with USB 2.0 (a new cable) or FireWire 800; both ways it returned the same "indexing a file failed"-type messages in the TM Buddy and system.log.
Any further suggestions are appreciated!
Thanks!
(example) from the Time Machine Buddy widget:
Starting standard backup
Backing up to: /Volumes/[BackupVolumeNameHere]/Backups.backupdb
Error parsing SystemMigration.log to determine source volume of system migration.
No pre-backup thinning needed: 63.75 GB requested (including padding), 1.57 TB available
Waiting for index to be ready (100)
Waiting for index to be ready (100)
Waiting for index to be ready (100)
Waiting for index to be ready (100)
Waiting for index to be ready (100)
Waiting for index to be ready (100)
Waiting for index to be ready (100)
Waiting for index to be ready (100)
Indexer unavailable (1)
Waiting for index to be ready (100)
... (and on like that)
from system.log (filtered with search, "backupd"):
Sep 28 00:31:54 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 00:32:21 [ComputerNameHere] com.apple.backupd[252]: Indexer unavailable (1)
... and on like that, until ...
Sep 28 04:32:16 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 04:33:16 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 04:34:16 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 04:35:16 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 04:36:16 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 04:37:16 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 04:38:16 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 04:39:16 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 04:40:16 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 04:40:22 [ComputerNameHere] com.apple.backupd[252]: Copied 0 bytes of 53.1 GB, 0 of 939187 items
Sep 28 05:19:02 [ComputerNameHere] com.apple.backupd[252]: Indexing a file failed. Returned 200 for: /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/CarbonC ore.framework/Versions/A/_CodeSignature/CodeResources, /Volumes/[BackupVolumeNameHere]/Backups.backupdb/[iMacNameHere]/2010-09-27-1826 58.inProgress/CB67F2B5-BB62-471C-832F-0E7FD1E8C4A6/Macintosh HD/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/Carbo nCore.framework/Versions/A/_CodeSignature/CodeResources
Sep 28 05:19:02 [ComputerNameHere] com.apple.backupd[252]: Aborting backup because indexing a file failed.
Sep 28 05:19:02 [ComputerNameHere] com.apple.backupd[252]: Stopping backup.
Sep 28 05:19:02 [ComputerNameHere] com.apple.backupd[252]: Copied 126680 files (20.9 GB) from volume Macintosh HD.
Sep 28 05:19:02 [ComputerNameHere] com.apple.backupd[252]: Copy stage failed with error:11
Sep 28 05:19:07 [ComputerNameHere] com.apple.backupd[252]: Backup failed with error: 11
Sep 28 05:25:28 [ComputerNameHere] com.apple.backupd[252]: Starting standard backup
Sep 28 05:25:28 [ComputerNameHere] com.apple.backupd[252]: Backing up to: /Volumes/[BackupVolumeNameHere]/Backups.backupdb
Sep 28 05:25:29 [ComputerNameHere] com.apple.backupd[252]: Error parsing SystemMigration.log to determine source volume of system migration.
Sep 28 05:25:29 [ComputerNameHere] com.apple.backupd[252]: No pre-backup thinning needed: 39.99 GB requested (including padding), 1.73 TB available
Sep 28 05:25:29 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 05:26:29 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 05:27:29 [ComputerNameHere] com.apple.backupd[252]: Indexer unavailable (1)
... and on like that again, until ...
Sep 28 08:22:10 [ComputerNameHere] com.apple.backupd[252]: Copied 0 bytes of 27.8 GB, 0 of 939187 items
Sep 28 08:31:15 [ComputerNameHere] com.apple.backupd[252]: Indexing a file failed. Returned 1 for: /Library/Application Support/iPhoto/Themes/Shared/Card/PaperHearts/Icons/paper_hearts-V-oustide-roun d-text-red.tiff, /Volumes/[BackupVolumeNameHere]/Backups.backupdb/[iMacNameHere]/2010-09-27-1826 58.inProgress/91C738D1-2AB3-481D-861F-9A5FBEC2B546/Macintosh HD/Library/Application Support/iPhoto/Themes/Shared/Card/PaperHearts/Icons/paper_hearts-V-oustide-roun d-text-red.tiff
Sep 28 08:31:15 [ComputerNameHere] com.apple.backupd[252]: Aborting backup because indexing a file failed.
Sep 28 08:31:15 [ComputerNameHere] com.apple.backupd[252]: Stopping backup.
Sep 28 08:31:15 [ComputerNameHere] com.apple.backupd[252]: Copied 89460 files (229 KB) from volume Macintosh HD.
Sep 28 08:31:15 [ComputerNameHere] com.apple.backupd[252]: Copy stage failed with error:11
Sep 28 08:31:20 [ComputerNameHere] com.apple.backupd[252]: Backup failed with error: 11
Sep 28 09:25:28 [ComputerNameHere] com.apple.backupd[252]: Starting standard backup
Sep 28 09:25:28 [ComputerNameHere] com.apple.backupd[252]: Backing up to: /Volumes/[BackupVolumeNameHere]/Backups.backupdb
Sep 28 09:25:28 [ComputerNameHere] com.apple.backupd[252]: Error parsing SystemMigration.log to determine source volume of system migration.
Sep 28 09:25:28 [ComputerNameHere] com.apple.backupd[252]: No pre-backup thinning needed: 33.41 GB requested (including padding), 1.72 TB available
Sep 28 09:25:28 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 09:26:28 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
... and on like that again, until ...
Sep 28 11:21:30 [ComputerNameHere] com.apple.backupd[252]: Waiting for index to be ready (100)
Sep 28 11:22:04 [ComputerNameHere] com.apple.backupd[252]: Copied 0 bytes of 27.8 GB, 0 of 939187 items
Sep 28 11:31:09 [ComputerNameHere] com.apple.backupd[252]: Indexing a file failed. Returned 1 for: /Library/Application Support/iPhoto/Themes/Shared/Card/SimpleParchment/SimpleParchmentHM_FrontV.png, /Volumes/[BackupVolumeNameHere]/Backups.backupdb/[iMacNameHere]/2010-09-27-1826 58.inProgress/E252969A-FF5D-418A-B61C-15EFC7784C20/Macintosh HD/Library/Application Support/iPhoto/Themes/Shared/Card/SimpleParchment/SimpleParchmentHM_FrontV.png
Sep 28 11:31:09 [ComputerNameHere] com.apple.backupd[252]: Aborting backup because indexing a file failed.
Sep 28 11:31:09 [ComputerNameHere] com.apple.backupd[252]: Stopping backup.
Sep 28 11:31:09 [ComputerNameHere] com.apple.backupd[252]: Copied 90086 files (37.7 MB) from volume Macintosh HD.
Sep 28 11:31:09 [ComputerNameHere] com.apple.backupd[252]: Copy stage failed with error:11
Sep 28 11:31:14 [ComputerNameHere] com.apple.backupd[252]: Backup failed with error: 11

Hello again,
I ran the 10.6.4 Combo update installer, and followed up with Repair Permissions. There was one issue in the latter that I was curious about:
Warning: SUID file "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/MacOS/ARDAg ent" has been modified and will not be repaired.
I'm guessing that's not really related. In any case, I started running a new initial backup in TM which got hung up with the following:
messages from the Time Machine Buddy widget:
Starting standard backup
Backing up to: /Volumes/(backupvolume)/Backups.backupdb
Error parsing SystemMigration.log to determine source volume of system migration.
Backup content size: 64.7 GB excluded items size: 15.7 GB for volume Macintosh HD
No pre-backup thinning needed: 58.82 GB requested (including padding), 1.70 TB available
Waiting for index to be ready (100)
Waiting for index to be ready (100)
Indexer unavailable (1)
Indexing a file failed. Returned 1 for: /Library/Application Support/GarageBand/Magic GarageBand/06. Funk.mwand, /Volumes/(backupvolume)/Backups.backupdb/(computername)/2010-10-15-151841.inPro gress/8CB20070-9CFE-4667-A590-17730C868861/Macintosh HD/Library/Application Support/GarageBand/Magic GarageBand/06. Funk.mwand
Aborting backup because indexing of file failed.
Stopping backup.
Copied 74447 files (15.2 GB) from volume Macintosh HD.
Copy stage failed with error:11
Backup failed with error: 11
messages in system.log (filtered with search "backupd"):
Oct 15 15:18:40 (computername) com.apple.backupd[470]: Starting standard backup
Oct 15 15:18:40 (computername) com.apple.backupd[470]: Backing up to: /Volumes/(backupvolume)/Backups.backupdb
Oct 15 15:18:41 (computername) com.apple.backupd[470]: Error parsing SystemMigration.log to determine source volume of system migration.
Oct 15 15:18:42 (computername) com.apple.backupd[470]: Backup content size: 64.7 GB excluded items size: 15.7 GB for volume Macintosh HD
Oct 15 15:18:42 (computername) com.apple.backupd[470]: No pre-backup thinning needed: 58.82 GB requested (including padding), 1.70 TB available
Oct 15 15:18:42 (computername) com.apple.backupd[470]: Waiting for index to be ready (100)
Oct 15 15:19:42 (computername) com.apple.backupd[470]: Waiting for index to be ready (100)
Oct 15 15:19:51 (computername) com.apple.backupd[470]: Indexer unavailable (1)
Oct 15 15:19:53 (computername) mds[475]: (Normal) DiskStore: Creating index for /Volumes/(backupvolume)/Backups.backupdb
Oct 15 15:39:55 (computername) com.apple.backupd[470]: Indexing a file failed. Returned 1 for: /Library/Application Support/GarageBand/Magic GarageBand/06. Funk.mwand, /Volumes/(backupvolume)/Backups.backupdb/(computername)/2010-10-15-151841.inPro gress/8CB20070-9CFE-4667-A590-17730C868861/Macintosh HD/Library/Application Support/GarageBand/Magic GarageBand/06. Funk.mwand
Oct 15 15:39:55 (computername) com.apple.backupd[470]: Aborting backup because indexing of file failed.
Oct 15 15:39:55 (computername) com.apple.backupd[470]: Stopping backup.
Oct 15 15:39:56 (computername) com.apple.backupd[470]: Copied 74447 files (15.2 GB) from volume Macintosh HD.
Oct 15 15:39:56 (computername) com.apple.backupd[470]: Copy stage failed with error:11
Oct 15 15:40:01 (computername) com.apple.backupd[470]: Backup failed with error: 11
Currently, TM is attempting to (resume?) back up again. Would you suggest leaving it alone, or proceeding next with a re-install of Snow Leopard from the install DVD (followed by 10.6.4 again)?
Thanks again!

"Invalid Index Key" Error - External HFS+ Drive

So I've got this external drive (Seagate Freeagent Go) that I formated with the Journaled filesystem. All of a sudden yesterday I could not access the drive after restarting my computer and when I could no longer see it on my desktop I opened Disk Utility. DU was able to see the drive and the partition but couldn't mount it, and when I ran a Verify/Repair I got the following:
Verify and Repair volume “Artimis”
Checking Journaled HFS Plus volume.
Checking Extents Overflow file.
Checking Catalog file.
Invalid index key
Rebuilding Catalog B-tree.
The volume Artimis could not be repaired.
Error: Filesystem verify or repair failed.
Can anyone help me with a potential fix? I've had no power surges and had just been using the drive with no issues the night before

It's possible that Disk Warrior may be able to repair the drive's directory. If not you will have to reformat it.

CTXCAT search index Issue - trying to index multi columns

i can index more than one column in the same table using MULTI_COLUMN_DATASTORE but when the index type is CONTEXT
but i need to index more than one column ,when the index type is CTXCAT
putting into considerations that i found that MULTI_COLUMN_DATASTORE doesn't work with ctxcat
if anybody knows any other way pleaze Help...
thanks in advance

MULTI_COLUMN_DATASTORE cannot be used with CTXCAT search as the this parameter is not supported
i am asking about abnother way,or a work around MULTI_COLUMN_DATASTORE
in order to work

Criteria for choosing to create index on column?

Hello,
This maybe is a trivial question. I have been reading on performance tuning of SQL queries. What criteria is used to determine which column needs to have an index?
If a query is as follows:
Select * from table where column1=<value> and column2=<value> and column3=<value>;What is the criteria for choosing a particular column to be indexed?. Is it the column containing the higher number of unique rows so that index selectivity is high?
Thanks

For that particular query, an index on all three columns would be best. However, that's probably not the only query on that table, and you have to take them into account as well.
What's the main use of your table? What functionality is used most or is most important? Design your index scheme to assist those queries if possible.
If you have a book, would you use the index? If it's a technical reference book, or an encyclopedia, yes. If it's a novel you read from start to finish, probably not. And if you are reading the Oracle Concepts Manual and you want to search for the paragraphs containing the word "database", would you use an index? And if you search for the logwriter process (LGWR)? It's just about common sense in general: you'll want an index to be selective.
Another side of the story is that indexes slow down inserts, deletes and updates, so you'll have to make a trade-off: is this penalty worth the speedup of a few queries?
Regards,
Rob.

Index Multiple Column of Multiple Tables

Hi All,
I would like to know how to create a index which can search through all column in my database tables. Eg: I have 30
tables and every tables have around 10 columns. I want to create a index which can search through the columns in
these tables.
I know that User_DataStore can helps in create multiple column search across multiple tables. But in my case the BLOB
created will be very huge. Any work around? I mean is there any solutions like concatenated datastore?
Thank You.
Regards,
LG Tan

Hi,
I figured out how to do this today. The first thing is that the type of index you need is a USER_DATASTORE.
The idea behind this type of index is pretty straight forward but the documentation does a very good job of not drawing attention to just how powerful it is.
The idea behind a USER_DATASTORE is that you can write your own stored procedure to extract the data that you want to index and return it to the indexer. Take an example where you have a master table which contains enough information to allow you to find associated data in other tables i.e. a shared key. The idea is that when you set up a USER_DATASTORE index, you specify the name of a stored procedure that the indexer will call for each row in the master table. The stored procedure has one input and one output parameter, rowid (in) and clob (out).
When the index is created, the stored procedure you specify is, as I said above, called for each row in the master table. Your stored procedure uses this ROWID to extract the shared key (this can be anything you want) from the master table and uses this to build the necessary SELECT statement to retrieve the related data from the other tables. The rest of the stored procedure simply appends the data returned from your select statement to the return CLOB. The indexer then indexes the inforamation in this CLOB and discards the data.
The index can of course only return hits against the master table. It's up to your application to extract shared key from the returned row(s), bind to the other tables and present the results.
You will find a basic example of how to implement USER_DATASTORES in the Oracle Text Reference Guide (http://download.oracle.com/otndoc/oracle9i/901_doc/text.901/a90121.pdf). Feel free to email me if you want some example code.
Dean

To index a column externally

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