Planet MySQL Planet MySQL: Meta Deutsch Español Français Italiano 日本語 Русский Português 中文
Showing entries 1 to 6

Displaying posts with tag: Ms SQL Server (reset)

MySQL Hacks: Preventing deletion of specific rows
+3 Vote Up -0Vote Down

Recently, someone emailed me:I have a requirement in MYSQL as follows:
we have a table EMP and we have to restrict the users not delete employees with DEPT_ID = 10. If user executes a DELETE statement without giving any WHERE condition all the rows should be deleted except those with DEPT_ID = 10.

We are trying to write a BEFORE DELETE trigger but we are not able to get this functionality.

I have seen your blog where you explained about …




  [Read more...]
MQL-to-SQL: A JSON-based query language for your favorite RDBMS - Part I
+3 Vote Up -0Vote Down

Yesterday, I wrote about how I think this year's MySQL conference will differ from prior editions. I also wrote that I will attend and that I will be speaking on MQL-to-SQL.

I promised I would explain a little bit more background about my talk, so here's the first installment.

Abstract:



  [Read more...]
A small issue of SQL standards
+2 Vote Up -0Vote Down

From a functional perspective, the core SQL support in all major and minor RDBMS-es is reasonably similar. In this light, it's sometimes quite disturbing to find how some very basic things work so differently across different products. Consider this simple statement:

SELECT  'a' /* this is a comment */ 'b'
FROM onerow

What should the result be? (You can assume that onerow is an existing table that contains one row)

It turns out popular RDBMS-es mostly disagree with one another.

In Oracle XE, we get this:

SELECT  'a' /* comment */ 'b'
*
ERROR …






  [Read more...]
MySQL and MS SQL Server
+0 Vote Up -0Vote Down

Recently, MySQL had an article comparing MySQL and SQL Server at  http://dev.mysql.com/tech-resources/articles/move_from_microsoft_SQL_Server.html

There is one clarification I would like to make to this article.  The article states that MS SQL Server has row locking, and while this is true, MS SQL Server doesn’t always use row locking and often will resort to page locking.  A page is 8k of data, so, in effect, many rows are locked at the same time even if only one row in that page is being updated.  …

  [Read more...]
Are MySQL stored procedures slow?
+0 Vote Up -0Vote Down

 

Yes, if compared to code in Java or C#. For example, this overly simple code took 284 seconds.

CREATE PROCEDURE CountTest()
begin
    declare counter int default 0;
    select now();
    repeat
        set counter = counter + 1;
    until counter > 120000000
    end repeat;
    select counter;
    select now();
end

Ignoring my off by one error, here is equivalent code in C# (the language …











  [Read more...]
Writing a Book: Building Pentaho Solutions
+0 Vote Up -0Vote Down

Ok - this has been stewing for some time now, and I think now is the right time to announce that I am working together with Jos van Dongen from Tholis Consulting to create a book for Wiley with the tentative title "Building Pentaho Solutions".

My personal aim is to make this book the primary point of reference for DBAs and Application Developers that are familiar with Open Source products like MySQL and PostgreSQL but have no prior BI skills, as well as …

  [Read more...]
Showing entries 1 to 6

Planet MySQL © 1995, 2014, Oracle Corporation and/or its affiliates   Legal Policies | Your Privacy Rights | Terms of Use

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.