Quaries Archives - Real Time DBA Magic

Using Read Only Tables

While visiting a customer, we had a conversation about the correct way to stop users from writing to code tables. The customer described his ancient logic: when he wanted to move table to a read only state, he removed the write (insert/update/delete) permissions from all of his users. That was good enough for him for years – since he started using this method way back in Oracle 8. All was well, util this week he found out that the table owner’s privileges could not be revoked – and due to a bug, someone accidentally deleted the table content…

So I asked him why didn’t they change it to read only tables and he had no idea what I am talking about.
Well, I wrote about read only table like 6 years ago (in Hebrew), but I never thought I should translate it – since it’s a fairly “old” (11gR1) feature and everybody knows about it, right?
Well, this week proved me wrong. Here is what I wrote about it years ago.

SQL Riddle: Find the Sum of ASCII Codes of Employee Names (solution)

Oracle, Quaries

Zahar Hilkevich (from the blog – https://sqlpatterns.wordpress.com – cool blog, you should check it out) posted a riddle on Facebook.
The question was:

“For every employee find the sum of ASCII codes of all the characters in their names. Write a single SELECT statement only.”

EMPNO ENAME       SUM_ASCII
----- ---------- ----------
 7788 SCOTT             397
 7876 ADAMS             358
 7566 JONES             383
 7499 ALLEN             364
 7521 WARD              302
 7934 MILLER            453
 7902 FORD              299
 7369 SMITH             389
 7844 TURNER            480
 7698 BLAKE             351
 7782 CLARK             365
 7654 MARTIN            459
 7839 KING              297
 7900 JAMES             368

I have seen the future and it is glorious: SQLcl the next generation of SQL*Plus

Oracle, Quaries, Scripts, SQLcl

The first time I started using commercial databases was in 1998, in my basic programming course. The course was split into segments and at the first databases lesson, if my memory serves me right, the instructor began the class with the words: “Today we will learn about databases – first, let’s connect to the database using SQLPlus”.

This amazing tool, which almost everyone who works with Oracle databases knows, is one of the simplest yet powerful command line interface for working with the database. SQLPlus has been with us for many, many years – I used to use it back when I was using Oracle 7 and that says a lot. Since this is one of the most convenient tools to understand, and while it’s not very user friendly it does work great with scripts and other automatic procedures. SQLPlus have great integration with the cluster tools – for example, if we’re using it to stop an instance (regular shutdown), the grid infrastructure is aware the shutdown was on purpose, and it will not try to start up the instance node again. It even has other Oracle tools provide its users and its capabilities often (AWR reports for example).

The fact that SQLPlus has been around for so many years could have been considered a disadvantage because we would think it might not have changed over the years but this is not the case. The tools did change over the years – features and other capabilities were added and that allows us to do cool stuff like output our result to HTML format or interact with our scripts. Unfortunately that’s pretty much everything and the basics of the tool did not change.

I Recently became aware of a new tool from Oracle which will ultimately replace SQLPlus. It’s name is SQLcl and I was really impressed.

Oracle ANSI SQL and the WITH syntax

Oracle, Quaries, Scripts

SQL language has been around for so long, that some people feel it never changes. This is obviously not true – SQL is a dynamic language that changes all the time: some changes come from the vendors themselves but often this is the result of the standard changing and Oracle adopting the new standard in a later version.

Let’s start with a short history lesson. As we all know, SQL is not a unique language for Oracle. It’s a common language with standards set by ANSI. The first version of the language standardization was presented back in 1986 with the issuance of SQL86. In 1992, a revised version of the language came out (SQL-92). When Oracle tried to implement this standard at full, they noticed that some of the things there are really different from how Oracle did things so it adopted only a part of the standard in Oracle RDBMS 8 (and 8i).
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14/01/2015/0 Comments/by Zohar Elkayam/Estimated Reading Time: 3 Minutes

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