Tom Kyte

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These are the most recently asked questions on Ask Tom
Updated: 12 hours 53 min ago

Versioning Data Model

Sat, 2017-11-11 01:46
Hi AskTom team, I'd like your ideas about the data model design and/or Oracle features that I could take advantage of to achieve the design goals described below. <u>Background:</u> I'm in the early stages of designing a data model for a bra...
Categories: DBA Blogs

Union all query missing lines

Sat, 2017-11-11 01:46
Hello Tom and Tom, Linked live sql shows a condensed and "moved-to-dual" query we are using with a far resemblance on our database. It's a couple of nested "union all" statements, where we would expect the outermost union (UNION2) to deliver the u...
Categories: DBA Blogs

Grant select on a View with grant option does not work

Sat, 2017-11-11 01:46
Hi, I have Schema_1 that owns table_1, table_2, table_3. Schema_1 creates View_1 using table_1, Schema_1 Creates View_2 using table_2, Schema_1 Creates View_3 using table_3. Schema_2 Creates View_4 using View_1, View_2 and View_3. Then ...
Categories: DBA Blogs

Identify patterns and create groups

Fri, 2017-11-10 07:35
I have data that looks like this: <code>create table t (a varchar2(30), b date); insert into t values (NULL,TO_DATE('2003/05/03 16:02:44', 'yyyy/mm/dd hh24:mi:ss')); insert into t values (NULL,TO_DATE('2003/05/03 17:02:44', 'yyyy/mm/dd hh24:mi...
Categories: DBA Blogs

optimistic search for most recent records

Fri, 2017-11-10 07:35
Hi, I have very large table which constantly grows. The search is executed by ID column, which is part of PK. <code> create table TEST ( ID varchar2(20) primary key, VALUE varchar2(20), CREATED_TS timestamp default := systimes...
Categories: DBA Blogs

selecting table column based on lookup table

Fri, 2017-11-10 07:35
Hi I am trying to get columns from a table only if that column value is set as "YES" in another lookup table. Please help me to get the query for the same. I have a lookup table like this: create table cust_bug_lookup(Title varchar2(100), ...
Categories: DBA Blogs

Partitioned table performance

Fri, 2017-11-10 07:35
We have a partitioned table with more than 200 columns and 60 indexes. It has 10 foreign keys with related indexes and the remaining indexes are global style. It partitioned in a yearly basis and sub-partitioned in company. Now, we're have perfor...
Categories: DBA Blogs

there is a Bug using MERGE and DUAL together

Fri, 2017-11-10 07:35
Consider please the follwing simple table: <code>create table table_1 (c1 varchar2(100), c2 varchar2(100));</code> If we apply the following MERGE command now (attend please the WHERE clause), we get: <code> merge into table_1 tb using (se...
Categories: DBA Blogs

How to hire a Lead Oracle DBA

Fri, 2017-11-10 07:35
Hi I'm a Junior Oracle DBA in the new company that I joined in. Our Lead Oracle DBA resigned and my company is screening for new applicants. The boss of our department might ask me to interview the potential Oracle Lead DBA candidate and a...
Categories: DBA Blogs

Formatting negative values to sort correctly but keep the formatting

Fri, 2017-11-10 07:35
I have an old and a new query. I need help with the new one. The old query works fine. For the new one, I can't seem to find a way to format two columns (latitude and longitude, I need 6 digits after the decimal) in such a way as they sort correctly....
Categories: DBA Blogs

Oracle Block Size

Thu, 2017-11-09 10:06
Hi Tom, I would be very grateful if you could share your thoughts on Oracle block size. "rule of thumb" is Oracle Database block sizes (2 KB or 4 KB) for online transaction processing (OLTP) or mixed workload environments and larger block size...
Categories: DBA Blogs

Where clause mix of AND and OR with()

Thu, 2017-11-09 10:06
Hello, I need to mix and or in where cluse: like: and con1 and (con2 or con3 or con4)... t_where := t_where || ' and a.field1 = ''' || l_1 || '''' || ' ( ' || 'a.field2 = ''' || l_2 || '''' || ' or ' || ......
Categories: DBA Blogs

sql loader and date

Thu, 2017-11-09 10:06
hi!!! i am using sqlloader, i have a table T in my database T (empno, start_date date, resign_date date) my data file has data like this (date format IN THE DATAFILE is 'YYYYMMDD') 1, 19990101,20001101 2, 19981215,20010315 3, 19950520...
Categories: DBA Blogs

Tabuler row no

Thu, 2017-11-09 10:06
In oracle forms 12c, I created data block with tabula, I changed the otem row number displayed to 10 row, I need to get current selected row no in this tabuler on form at run time not current_record, O mean this number between 1 to 10, I tried get ...
Categories: DBA Blogs

SGA_target is greater than the total physical memory on the server (Windows)

Thu, 2017-11-09 10:06
HI Tom, We have a databases running on 11.2.0.3 with memory parameters set as below: This is a windows server 2008 R2. SQL> show parameter sga NAME TYPE VALUE ------------------------------------ --...
Categories: DBA Blogs

What´s your oppinion about the DBA job in the future

Thu, 2017-11-09 10:06
Hi Tom, First, i would like to thank you for your site in web. I learn a lot of things with the doubts of my coleages registered in this site. I learn too how to explain to the developers using examples (like you). Well, i would like to know wh...
Categories: DBA Blogs

IS JSON is not working for Nested Jsons

Wed, 2017-11-08 15:46
Hi Team, In one of our table we have column which holds JSON format text. data will be inserted to this column from a file we receive from Vendor. While Inserting the data to this column we dont't validate whether its in JSON format or not but bef...
Categories: DBA Blogs

Error handling behavior change according to PLSQL_OPTIMIZE_LEVEL

Tue, 2017-11-07 21:26
We had faced a case in our application where error message disappear according to PLSQL_OPTIMIZE_LEVEL. I had isolated the problem in a simple script. Run this script, you will see that at first execution of the procedure "test_error_proc#" error i...
Categories: DBA Blogs

SQL Query based on performance

Tue, 2017-11-07 21:26
Hi Tom, There is a table say t_tab with columns a,b and c. Data in the table is huge(more than million). You run the following three statements: 1. select * from t_tab 2. select a,b,c from t_tab 3. select b,c,a from t_tab Will there be a diffe...
Categories: DBA Blogs

Fuzzy Matching in SQL

Tue, 2017-11-07 21:26
Is there any SQL construct that does fuzzy matching ? As an example , if I have the values as Monroe , Monroe Twp , Monroe Township , "Monroe Twp,NJ" , I would like to consider them as one value .
Categories: DBA Blogs

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