Submitted by Natalka Roshak on Mon, 2016-06-13 14:25
The CONNECT BY syntax provides a useful pseudocolumn, CONNECT_BY_ISLEAF, which identifies leaf nodes in the data: it’s 1 when a row has no further children, 0 otherwise. In this post, I’ll look at emulating this pseudocolumn using recursive WITH.
Submitted by Natalka Roshak on Fri, 2016-06-03 04:38
In my last post, I looked at using recursive WITH to implement simple recursive algorithms in SQL. One very common use of recursion is to traverse hierarchical data. I recently wrote a series of posts on hierarchical data, using Oracle’s CONNECT BY syntax and a fun example. In this post, I’ll be revisiting the same data using recursive WITH.
Submitted by Natalka Roshak on Tue, 2016-05-24 04:03
I recently had the opportunity to talk with Tom Kyte (!), and in the course of our conversation, he really made me face up to the fact that the SQL syntax I use every day is frozen in time: I’m not making much use of the analytic functions and other syntax that Oracle has introduced since 8i.
Submitted by Lalit Kumar B on Fri, 2014-05-02 09:39
One of the most important things that a developer does apart from just code development is, debugging. Isn’t it? Yes, debugging the code to fix the errors that are raised. But, in order to actually debug, we need to first capture them somewhere. As of now, any application has it’s own user defined error logging table(s).
Imagine, if the tool is rich enough to automatically capture the errors. It is very much possible now with the new SQL*PLus release 11.1
Submitted by learn-with-vide... on Sun, 2014-01-12 06:20
Finding gaps is classic problem in PL/SQL. The basic concept is that you have some sort of numbers (like these: 1, 2, 3, 5, 6, 8, 9, 10, 15, 20, 21, 22, 23, 25, 26), where there’s supposed to be a fixed interval between the entries, but some entries could be missing. The gaps problem involves identifying the ranges of missing values in the sequence. For these numbers, the solution will be as follows:
First, run the following code, to create tab1 table:
CREATE TABLE tab1
Submitted by John Watson on Sun, 2013-09-08 03:52
The inverted table format can deliver fast and flexible query capabilities, but is not widely used. ADABAS is probably the most successful implementation, but how often do you see that nowadays? Following is a description of how to implement inverted structures within a relational database. All code run on Oracle Database 12c, release 184.108.40.206.
Submitted by John Watson on Sun, 2013-09-01 11:22
There are three restrictions on indexing and partitioning: a unique index cannot be local non-prefixed; a global non-prefixed index is not possible; a bitmap index cannot be global. Why these limitations? I suspect that they are there to prevent us from doing something idiotic.
Submitted by John Watson on Sun, 2013-07-28 05:19
I see posts on Oracle related forums about various releases (anything that isn't 11.x or 12.x) being "unsupported". This is wrong. Of course you should upgrade any 9i or 10g databases, but you don't have to.
Submitted by anjugarg66 on Sun, 2013-07-28 03:42
In this post, I will demonstrate a new feature introduced in 12c : In database archiving. It enables you to archive rows within a table by marking them as invisible. This is accomplshed by means of a hidden column ORA_ARCHIVE_STATE. These invisible rows are not visible to the queries but if needed, can be viewed , by setting a session parameter ROW ARCHIVAL VISIBILITY.
-- Create test user uilm, tablespace ilmtbs
-- Connect as user uilm
-- create and populate test table (5 rows) ilmtab with row archival clause
Submitted by anjugarg66 on Sun, 2013-07-28 03:37
When you create a PDB, the database automatically creates and starts a service inside the CDB.The service has the same name as the PDB. It is possible that the name of the service will collide with an existing service name which is registered with the same listener. For example if two or more CDBs on the same computer system use the same listener, and the newly established PDB has the same service name as another PDB in these CDBs, then a collision occurs.
You must not attempt to operate a PDB that causes a collision with an existing service name.