I am using Oracle 11g Text,
AuthorTable : (a table for Author details)
AuthorId, AuthorName, AuthorDOB
ArticleTable : (a table for Article content) ArticleId, WrittenDate, PublishDate, ARTICLE_TXT (CLOB)
LocationTable : (a table for Location) LocationId, LocationState, LocationCity
ArticleAuthorAssocTable: (a table for Article-Author Association) AuthorId, ArticleId
LocAuthorAssocTable: (a table for Author-Location Association) AuthorId, LocationId, LocationStartDate, LocationEndDate
My query need to search for any input search term on ARTICLE_TXT along with any other query on PublishDate / WrittenDate / AuthorDOB / LocationCity / LocationStartDate range.
As I have to do a mixed-query, I started creating Composite Domain Index CDI on ArticleTable.
CREATE INDEX ARTICLE_TXT_CDI_IDX ON ArticleTable(ARTICLE_TXT)
INDEXTYPE IS ctxsys.CONTEXT
FILTER BY WrittenDate, PublishDate
and the query as
SELECT
/*+ domain_index_sort domain_index_filter(ARTICLE_TXT_CDI_IDX) */ article.ARTICLE_TXT,
author.AuthorName , article.WrittenDate, article.PublishDate, LocationTable.LocationCity ,location.LocationStartDate, location.LocationEndDate
FROM
ArticleTable article
INNER JOIN
ArticleAuthorAssocTable articleAuthorAssoc ON article.articleId = articleAuthorAssoc .articleId
INNER JOIN
AuthorTable author ON author.authorId= articleAuthorAssoc.authorId
INNER JOIN
LocAuthorAssocTable locAuthorAssoc req ON author.authorId = locAuthorAssoc.authorId
INNER JOIN
LocationTable location ON location .authorId = locAuthorAssoc.authorId
WHERE
CONTAINS(article.ARTICLE_TXT, 'Something') >0
AND author.AuthorDOB BETWEEN TO_DATE('01/01/2001','MM/DD/YYYY')
AND TO_DATE('12/31/2012','MM/DD/YYYY')
AND location.LocationId IN (1,2)
Now my questions are:
Is it possible to create Composite Domain Index with FILTER BY on
columns from different tables ?
Is there any other way to improve the above query ?
From my research, some options are using materialized view, function-based index, USER_DATASTORE
But unfortunately still not sure how to use them... Please help me with your knowledge.
Thanks
I think the best solution to this problem is to add a XML column to the ArticleTable where you combine all the required info of the article.
Then you need to add triggers to the involved tables to recreate this xml when data changes are happening.
This way you could index this xml column and search for very specific information, using section groups (eg like 'PATH_SECTION_GROUP')
Related
Currently I am trying to find all the unique indexes defined in a table which are NOT NULL for Oracle database. What I mean by that is, Oracle allows creating unique indexes on columns which are even defined as NULL.
So if my table has two unique indexes, I want to retrieve the particular unique index which is having all the columns having the NOT NULL constraints.
I did come up with this query:
select ind.index_name, ind_col.column_name, ind.index_type, ind.uniqueness
from sys.dba_indexes ind
inner join sys.dba_ind_columns ind_col on ind.owner = ind_col.index_owner and ind.index_name = ind_col.index_name
where ind.owner in ('ISADRM') and ind.table_name in ('TH_RHELOR') and ind.uniqueness IN ('UNIQUE')
The above query is giving me all the unique indexes with the associated columns, but I am not sure, how should I join the above query with ALL_TAB_COLS which has the NULLABILITY data for all the columns of a table.
I tried joining this table with indexes and tried subquery as well, but not getting appropriate results.
Hence, would request you to please comment on same.
Analytic functions and inline views can help.
The analytic functions let you return detailed data but also create a summary on that data, based on separate windows. The detailed results include index owner, index name, and column name, but the counts are only per index owner and index name.
The first inline view joins the three tables, returns the detailed information, and has analytic functions to generate the count of all columns and the count of all nullable columns. The second inline view only selects rows where those two counts are equal.
--Unique indexes and columns where every column is NOT NULL.
select owner, index_name, column_name
from
(
--All relevant columns and counts of columns and not null columns.
select
dba_indexes.owner,
dba_indexes.index_name,
dba_tab_columns.column_name,
dba_tab_columns.nullable,
count(*) over (partition by dba_indexes.owner, dba_indexes.index_name) total_columns,
sum(case when nullable = 'N' then 1 else 0 end)
over (partition by dba_indexes.owner, dba_indexes.index_name) total_not_null_columns
from dba_indexes
join dba_ind_columns
on dba_indexes.owner = dba_ind_columns.index_owner
and dba_indexes.index_name = dba_ind_columns.index_name
join dba_tab_columns
on dba_ind_columns.table_name = dba_tab_columns.table_name
and dba_ind_columns.column_name = dba_tab_columns.column_name
where dba_indexes.owner = user
and dba_indexes.uniqueness = 'UNIQUE'
order by 1,2,3
)
where total_columns = total_not_null_columns
order by 1,2,3;
Analytic functions and inline views are tricky but they're very powerful once you learn how to use them.
I have these three tables :
RESEARCHER(Re_Id, Re_Name, Re_Address, Re_Phone, Re_HomePhoneNumber,
Re_OfficeNumber, Re_FirstScore, Re_Second_Score)
PUBLICATION(Pub_ID, Pub_Title, Pub_Type, Pub_Publisher, Pub_Year,Pub_Country, Pub_StartingPage, Pub_Number_of_Page, Score1, Score2)
WRITTEN_BY(Re_Id, Pub_ID)
I want to change the authors of the publication “Introduction to Database System” to “Henry Gordon” and “Sarah Parker”.
The problem is in WRITTEN_BY table,I just store the researcher's ID and publication's ID.
My idea is to change the Re_Id in WRITTEN_BY by those names are "Henry Gorgon" , "Sarah Parker" , which are already existed in RESEARCHER table
UPDATE WRITTEN_BY
SET Re_Id = ....( SELECT Re_Id
FROM RESEACHER
WHERE Re_Name = ‘Henry Gordon’ OR Re_Name = ‘Sarah Paker’ )
WHERE Pub_ID IN ( SELECT Pub_ID
FROM PUBLICATION
WHERE Pub_Name = ‘Introduciton to Database system’ );
I have problem in the SET part,so how to write the SQL statement for that requirement?
Here is the sqlfiddle link for my schema : http://sqlfiddle.com/#!9/b9118/1
I'd use something like below query:
DELETE FROM WRITTEN_BY WHERE Pub_ID IN (
SELECT Pub_ID FROM PUBLICATION
WHERE Pub_Title = 'Introduciton to Database system' )
INSERT INTO WRITTEN_BY
SELECT Re_Id,Pub_Id
FROM RESEARCHER CROSS JOIN PUBLICATION
WHERE Re_Name = 'Henry Gordon' OR Re_Name = 'Sarah Paker'
AND Pub_Title like 'Introduciton to Database system'
SELECT * FROM WRITTEN_BY
The idea is to first drop the existing mapping- you should not update it- and the insert a new one.
The reason for delete/insert approach vs update in case of mapping table is justified in favor of delete/insert as most mapping tables contain many-many mapping and usually one-to-many mappings.
Initially we may have a book mapped to say n number of authors where n <>1 then we either add extra rows, or are left with extraneous rows.
See sample fiddle: http://sqlfiddle.com/#!6/a0e72/13
The real deal however is CROSS JOIN. This does not take any ON like other JOINs and is used to produce cartesian product type map.
We are restricting it to get only limited number of rows as per our need by adding suitable WHERE clauses
I have one complex SQL queries. One of the simple part of the queries looks like:
Query 1:
SELECT *
FROM table1 t1, table2 t2
WHERE t1.number = t2.number
AND UPPER(t1.name) = UPPER(t2.name)
AND t1.prefix = p_in_prefix;
Query 2:
SELECT *
FROM table1 t1, table2 t2
WHERE t1.number = t2.number
AND UPPER(t1.name) = UPPER(p_in_prefix || t2.name)
AND t1.prefix = p_in_prefix;
I have function based index on table1 as (number, UPPER(name)). I have function based index on my table2 as (number, UPPER(NAME)). p_in_prefix is a input parameter (basically a number).
Because of these indexes my Query 1 runs efficiently. But Query 2 has a performance issue, as in Query 2, 't2.name' is prefixed with p_in_prefix.
I can not create function based index for Query 2 because p_in_prefix is a input parameter and I don't know while creating index, what values it might hold. How to resolve performace issue in this scenario? Any hint/idea would be appreciated. If you require more information, please let me know.
Thanks.
Use AND UPPER(t1.name) = UPPER(p_in_prefix) || UPPER(t2.name).
As you have a function based index as UPPER(NAME) of table2, you should have an operand with the same expression in the query in order to make use of the function based index.
Using UPPER(p_in_prefix || t2.name) will not use the function based index as this does not match the function expression UPPER(NAME). Note here that using UPPER(t2.name) does not cause any problems as t2 is just a column alias.
Along with this, you can also pass an optimizer hint in your query in order to instruct the optimizer to use the index.
For more information read "Oracle Database 11g SQL" by Jason Price.
Also read Oracle Docs here and here and for optimizer hints here.
I have a query as follows
select *
from
( select id,sum(amt) amt from table_t group by id
) t inner join table_v v on (v.id = t.id)
order by t.amt desc;
table_t has no index and has 738,000 rows and table_v has an index on id and has 158,000 rows.
The query currently fetches the results in 10 seconds.
The explain query plan shows a full table scan.. How can I improve the performance here ?
If I add an index on id for table_t will it help. Because I am using it in a subquery ?
If you have an index on (id,amt) you would minimise the work in the group by/summation process (as it could read the index). If both columns are nullable then you may need to add a "where id is not null" so it will use the index. [That's implied by the later join on id, but may not get inferred by the optimizer.]
Next step would be to use a materialized view for the summation, maybe with an index on (amt,id) (which it could use to avoid the sort). But that is refreshed either at a commit or on request or at scheduled intervals. It doesn't help if you need to do this query as part of a transaction.
Both the index and the materialized view would add work to inserts/updates/deletes on the table but save work in this query.
I have two entities: Master and Details.
When I query them, the resulting query to database is:
SELECT [Extent2]."needed columns listed here", [Extent1]."needed columns listed here"
FROM (SELECT * [Details]."all columns listed here"...
FROM [dbo].[Details] AS [Details]) AS [Extent1]
LEFT OUTER JOIN [dbo].[Master] AS [Extent2] ON [Extent1].[key] = [Extent2].[key]
WHERE [Extent1].[filterColumn] = #p__linq__0
My question is: why not the filter is in the inner query? How can I get this query? I've tried a lot of EF and Linq expressions.
What I need is something like:
SELECT <anything needed>
FROM Master LEFT JOIN Details ON Master.key = Details.Key
WHERE filterColumn = #param
I'm having a full sequential scan in both tables, and in my production environment, I have milions of rows in each table.
Thanks a lot !!
Sometimes The entity Framework does not produce the best query. You can do a few of the following to optimize.
Modify the linq statement (test with
LINQPad)
Create a stored proc and map the stored proc to return an entity
Create a view that handles the join and map the view to a new
entity