Tom Kyte

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Updated: 3 days 14 hours ago

Performance & features of OCCI vs OCI

Thu, 2016-07-07 09:06
I'm going to develop an application that needs max performance. I will need: - batch inserts of BLOB - batch updates of BLOB - batch select of BLOB I consider to use OCCI but I'm not sure if it supports all optimizations that are done in OCI. ...
Categories: DBA Blogs

Materialized view logs and unique indexes

Thu, 2016-07-07 09:06
I have a table with moderate DML activity, a materialized view log on that table, and one materialized view on a remote database. After some activity in the source app, I can see multiple rows in the MV log with the same m_row$$, with a DMLTYPE$ v...
Categories: DBA Blogs

Best Data Type To use

Thu, 2016-07-07 09:06
I've a Table with columns EMPCODE,DAY1,DAY2...DAY31 I've to loop from Day1 to Day31 so what is the best way of doing this,If I should use collections then how should I assign Day1--31 to a Collection and what Collection Should I use. Can anyone p...
Categories: DBA Blogs

Oracle doubts

Wed, 2016-07-06 14:46
c d f ---- ---- ---- 1 a 100 1 b 200 Output: 1 a 100 b 200
Categories: DBA Blogs

cannot fetch plan for SQL_ID: 9m7787camwh4m, CHILD_NUMBER: 0

Wed, 2016-07-06 14:46
I am using PL/SQL in front end and Oracle 11gR2 in back end to developing a db app. In the middle of time, I am going to check hard parsed execution plan of one sql statment. What make me surprised is that the PL/SQL Developer seems has no capability...
Categories: DBA Blogs

Do bind variables in APEX trigger row by row processing?

Wed, 2016-07-06 14:46
To start this off, I kind of have a solution for my problem, I'm just trying to understand the mechanics behind it. Ok, here's the set-up: - I have a very simple APEX page: a report on a view + 2 date pickers to filter the data; - The query is a...
Categories: DBA Blogs

why does "select user from dba_users" work?

Wed, 2016-07-06 14:46
Hi all, I accidently typed today "select <b>user</b> from dba_users" in SQLPlus instead of "select <b>username</b> from dba_users" and it worked. Not like the correct SQL would have, but i got 21 rows (which is the correct number of users in the dat...
Categories: DBA Blogs

Slow query because the cardinality estimate is wrong for joins on foreign keys

Wed, 2016-07-06 14:46
While investigating a very slow query in our OLTP db, I noticed that Oracle severly under estimates the cardinality for joins that are on foreign key. The following script replicates the issue. create table A (part number not null, rec number not...
Categories: DBA Blogs

Tune order by clause in query.

Wed, 2016-07-06 14:46
Hi Tom, In the below query order by is taking a lot of time. so i thought of creating a composite index on columns that are present in the order by clause and force that index using hint. <b>But my problem is, here i have to fetch data of lo...
Categories: DBA Blogs

I need to delete 18000 rows from a table but where clause condition varies. How to complete this deletion in simple way

Wed, 2016-07-06 14:46
I need to delete 18000 rows from a table but where clause condtion varies for each set of records. A particular where clause condition can delete 3 records. Another particular where clause condition can delete 1 record. I combined both delete stat...
Categories: DBA Blogs

where are the executed statments stored?

Wed, 2016-07-06 14:46
suppose i execute a plsql block , all the statments are not executed. Only high load statments are executed. How to see which of the statements are executed and where are they stored, Like which view/table?
Categories: DBA Blogs

Cloud Raining - Where is Oracle with the Cloud - Is the DB Giant sleeping ?

Wed, 2016-07-06 14:46
Hello AskTom Team, I have been working with Oracle Database for over a decade and half. With the recent shift of Companies wanting to put their systems in Cloud rather then on prem What is the future of Oracle. I just attended a...
Categories: DBA Blogs

Inner join vs Where

Wed, 2016-07-06 14:46
What is the best practice use "Inner Join" o "Where" Example Example A select DISTINCT(ET.DESCRIPTION) FROM EVENTTYPE ET INNER JOIN EVENTDCO E ON E.EVENTTYPEID = ET.EVENTTYPEID INNER JOIN CONTEXTOPERATION CTX ON E.OPERATIONPK ...
Categories: DBA Blogs

ora-01008, what is the bind variable's name?

Tue, 2016-07-05 20:26
Good time of day, Tom! I run several SQL via DBMS_sql package. Each of that SQL has a set of bind variables. Is there any feature to get a list of variables' names for given SQL? For instance. I wonder to get a list of ':v_name',':p_result' ...
Categories: DBA Blogs

Generate tree paths for hierarchy

Tue, 2016-07-05 20:26
Hello , I have one question which are asked into interview ,To make a tree when user insert a node into table its path get automatically reflected into table Table: Tree ---------------------- node(int) parentNode(int) path(...
Categories: DBA Blogs

LEAST AND GREATEST functions

Tue, 2016-07-05 20:26
Hello, I am trying to use the below SQL : SELECT least ( DECODE (:VAR1, 9999, NULL, :VAR1), DECODE (:VAR2,9999, NULL,:VAR2) ) FROM DUAL; VAR1 & VAR2 need to be NUMBERs (not varchar) the above SQL seems to work for all numbers exce...
Categories: DBA Blogs

trigger

Tue, 2016-07-05 20:26
Hi, my table is with fist name , last name , status. Now the thing is I want to change the status to "APPROVED" as soon as I made the entry in last name, if last name column is empty status should be default lets say "PENDING". I tried it u...
Categories: DBA Blogs

High Soft Parsing

Tue, 2016-07-05 02:06
Hi Tom, We are experiencing high Soft parsing in our databases , though we have enabled session cached cursors and all our SQL/PL SQL blocks using bind variables. We are using Pro C as a host language interact with the back end database. Load...
Categories: DBA Blogs

Can we do a CTAS (Create table as) without the NOT NULL constraints?

Tue, 2016-07-05 02:06
Can we do a CTAS (Create table as) and create the new table without the NOT NULL constraints? select * from v$version; Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production PL/SQL Release 11.2.0.3.0 - Production CORE ...
Categories: DBA Blogs

Format the Number for display

Tue, 2016-07-05 02:06
<code>Hello Guru, Q1) I need to display numbers from a database in a specific format. Table Tn (n number(6,3)); The format is 999.999 SQL> insert into tn values( 123.123) ; 1 row created. SQL> insert into tn values(0) ; 1 row created. SQL...
Categories: DBA Blogs

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