EBR – Part 3: Changing a Package Body (the Solution)

This is a link to an index page for all the parts of the series

This is part 3 of a post series about EBR.
In part 1 we created the baseline model and code – a table (PEOPLE) and two packages (PEOPLE_DL and APP_MGR).
In part 2 we saw that even a simple change – such as a package body compilation – can be dangerous in a busy system.
In this post we’ll see (more...)

EBR – Part 2: Changing a Package Body (the Problems)

This is part 2 of a post series about EBR.
In part 1 we created the baseline model and code – a table (PEOPLE) and two packages (PEOPLE_DL and APP_MGR).
In this post we’ll start handling the first type of change request: changing a package body.

The Task

We need to change the implementation of the PEOPLE_DL package; i.e. we need to change the package body.
There are no API changes (the package spec (more...)

EBR – Part 1: Overview and Setup

I have been using EBR in a real production system for more than 4 years now.
EBR – an acronym for Edition-Based Redefinition – is a powerful and unique feature (or, more precisely, a set of features) that enables patching and upgrading live Oracle-based applications in an online fashion, with zero downtime.

As an Oracle Developer and DBA I find EBR one of the most important tools in my toolkit, and I take advantage of (more...)

ODC Appreciation Day: Collections in SQL

Here’s my contribution to the ODC Appreciation Day.

Overview

Last week I had the privilege to participate in the EOUC Database ACES Share Their Favorite Database Things session at Oracle OpenWorld, so I think that the best topic to write about, as part of the ODC Appreciation Day, is the one I talked about in this session.
My 5-minute presentation was about Collections in SQL.

Collections are very useful in PL/SQL development. This is (more...)

RETURNING INTO – Enhancement Suggestion

The RETURNING INTO clause is one of my favorite features.
It returns data from the rows that have been affected by the DML statement, and as I wrote in this previous post:
For INSERT it returns the after-insert values of the new row’s columns.
For UPDATE it returns the after-update values of the affected rows’ columns.
For DELETE it returns the before-delete values of the affected rows’ columns.

For INSERT there are no before-insert (more...)

Implementing Arc Relationships with Virtual Columns? Or Not?

I wrote a post some time ago about implementing arc relationships using virtual columns.
Recently, Toon Koppelaars wrote a detailed and reasoned comment to that post. Since I admire Toon, getting his point of view on something that I wrote is a privilege for me, regardless if he agrees with me or disagrees (and just to be clear, it’s the latter this time). I think that having a public (and civilized) discussion – this time (more...)

Write (Even) Less with More – VALIDATE_CONVERSION

I wrote the post Write Less with More – Part 8 – PL/SQL in the WITH Clause in November 2015, when the latest released Oracle version was 12.1.
In that post I explained about PL/SQL in the WITH Clause – a new 12.1 feature – and demonstrated it using the following example:

todo8

Since then Oracle 12.2 was released, and introduced a new feature that enables solving this task in a simpler way – the VALIDATE_CONVERSION function. This function gets an expression and a data type, and returns 1 if the expression can be converted to the data type and 0 if not.
Using the same setup from the original post, the requested query becomes as simple as:

> select *
  from   people
  where  general_info is not null
  and    validate_conversion(general_info as date, 'dd/mm/yyyy') = 1;

PERSON_ID FIRST_NAME LAST_NAME       GENERAL_INFO
---------- ---------- --------------- --------------------
       102 Paul       McCartney       18/6/1942
       202 Ella       Fitzgerald      15/6/1996
       203 Etta       James           20/1/2012

In addition to introducing the new VALIDATE_CONVERSION function, the older CAST and some of the TO_* conversion functions have been enhanced in Oracle 12.2 and include a DEFAULT ON CONVERSION ERROR clause, so when data type conversion fails we can get some default value instead of an error.

> select p.person_id,
         p.first_name,
         p.last_name,
         to_date(p.general_info default null on conversion error, 'dd/mm/yyyy') my_date
  from   people p;

 PERSON_ID FIRST_NAME LAST_NAME       MY_DATE
---------- ---------- --------------- ----------
       101 John       Lennon
       102 Paul       McCartney       18/06/1942
       103 Ringo      Starr
       104 George     Harisson
       201 Louis      Armstrong
       202 Ella       Fitzgerald      15/06/1996
       203 Etta       James           20/01/2012
       317 Julie      Andrews

8 rows selected.

The post Write (Even) Less with More – VALIDATE_CONVERSION appeared first on @DBoriented.

PL/SQL in SQL in View in SQL in PL/SQL

I presented “Write Less (Code) With More (Oracle 12c New Features)” yesterday at OGh Tech Experience 2017.
One of the features I talked about was PL/SQL in the WITH Clause. One of the restrictions of this feature is that you cannot embed a static SQL query, that contains PL/SQL in the WITH clause, in PL/SQL (see the section PL/SQL in SQL in PL/SQL in this post).
I was asked, regarding this restriction, if it’s (more...)

RETURNING INTO

The RETURNING INTO clause is one of my favorite PL/SQL features. It allows to write less code, improves readability and reduces context switches between PL/SQL and SQL.
In this post I’d like to highlight some less-known characteristics of the RETURNING INTO clause and emphasize differences that exist when it is used in different DML statements.

Supported Statements

The RETURNING INTO clause is supported by the UPDATE, DELETE, and single-table single-row (“values-based”) INSERT statements.
It is (more...)

Adding a Column with a Default Value and a Constraint

The Constraint Optimization series:


In the previous parts of this series I showed that Oracle does a nice optimization – that may save plenty of time – when we add in a (more...)