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Displaying posts with tag: DBA (reset)
AlmaLinux MySQL Workbench

AlmaLinux doesn’t natively support MySQL Workbench but these notes will help you install it. The great news is that MySQL Workbench works perfectly once you’ve installed all the dependent libraries. It’ll look like the following:

Disclaimer of sorts:

AlmaLinux is an open-source, community-driven project that intends to fill the gap left by the demise of the CentOS stable release. AlmaLinux is a 1:1 binary compatible fork of RHEL® 9 and it is built by the AlmaLinux OS Foundation as a standalone, completely free OS. The AlmaLinux OS Foundation will support future RHEL® releases by updating AlmaLinux. Ongoing development efforts are governed by the members of the community.

You can download MySQL Workbench from the following website:

When you open this page, select the Red Hat Enterprise Linux 9 / Oracle Linux 9 (x86, 64-bit), RPM Package from the dropdown …

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AlmaLinux MySQL+Perl

A quick primer on Perl programs connecting to the MySQL database. It’s another set of coding examples for the AlmaLinux instance that I’m building for students. This one demonstrates basic Perl programs, connecting to MySQL, returning data sets by reference and position, dynamic queries, and input parameters to dynamic queries.

  1. Naturally, a is a great place to start:
    # Hello World program.
    print "Hello World!\n";

    After setting the permissions to -rwxr-xr-x. with this command:

    chmod 755

    You call it like this from the Command-Line Interface (CLI):


    It prints:

    Hello World!
  2. Next, a program lets us test the Perl::DBI connection to the MySQL database.
    # Import libraries.
    use strict;
    use warnings;
    use v5.10;     # for …
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MySQL Query from JSON

One of my students asked how you could get JSON data out in tabular format. I said they should look at Øystein Grøvlen’s JSON_TABLE – Best of Both Worlds blog post from 2018. Unfortunately, the student wanted another example with the Video Store model that we use in class.

For clarity, all path definitions start with a $ followed by other selectors:

  • A period followed by a name, such as $.website
  • [N] where N is the position in a zero-indexed array
  • The .[*] wildcard evaluates all members of an object
  • The [*] wildcard evaluates all members of an array
  • The prefix and suffix wildcard, **, evaluates to all paths that begin with the named prefix and end with the named suffix

So, here’s a quick supplement to what’s already there. It assumes you created an …

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MySQL Backslashes

Yesterday, I wrote a blog post that showed you how to write a query returning a JSON structure for a 1:many relationship. The relationship was between the member and contact table. It returns one account_number from the member table and a list of first_name and last_name columns from the contact table in a JSON structure.

One of my students asked why I choose to strip the backslashes with Python, and my reply was the SQL was already complex for most blog readers. The student asked but how would you do it in SQL. OK, that’s a fair question for two reasons. First, you don’t need to do in your local programs because it’ll run faster on the server. Second, if you strip the backslashes you can insert it into a standard JSON column. This blog post will show you how to do both.

You would use three REGEXP_REPLACE function calls, like:

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Is SQL Programming

Is SQL, or Structured Query Language, a programming language? That’s a great question! A question that many answer with emphasis: “No, SQL is not a programming language!” There are some who answer yes; and they usually qualify that answer with something like: “SQL is a programming language designed to communicate with relational databases.”

It strikes me that those saying “yes” are saying that SQL is only a collection of interface methods to read from and write to a database engine. Those saying SQL is not a programming language often qualify that a programming language must have conditional logic and iterative structures, which don’t exist in SQL.

There’s a third group that are fence sitters. They decline to say whether SQL is a programming language, but they also say individuals who only write SQL aren’t programmers. That’s a bit harsh from my perspective.

Before …

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Node.js MySQL Error

While I blogged about how to setup Node.js and MySQL almost two years ago, it was interesting when a student ran into a problem. The student said they’d configured the environment but were unable to use Node.js to access MySQL.

The error is caused by this import statement:

const mysql = require('mysql') 

The student got the following error, which simply says that they hadn’t installed the Node.js package for MySQL driver.

    throw err;

Error: Cannot find module 'mysql'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:636:15)
    at Function.Module._load (internal/modules/cjs/loader.js:562:25)
    at Module.require (internal/modules/cjs/loader.js:692:17)
    at require (internal/modules/cjs/helpers.js:25:18)
    at Object. (/home/student/Data/cit325/oracle-s/lib/Oracle12cPLSQLCode/Introduction/query.js:4:15)
    at Module._compile …
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MySQL Partitioned Tables

MySQL Partitioned Tables

Learning Outcomes

  • Learn about List Partitioning.
  • Learn about Range Partitioning.
  • Learn about Columns Partitioning.
  • Learn about Hash Partitioning.
  • Learn about Key Partitioning.
  • Learn about Subpartitioning.

Lesson Material

MySQL supports partitioning of tables. It supports range, list, hash, and key partitioning. Range partitioning lets you partition based on column values that fall within given ranges. List partitioning lets you partition based on columns matching one of a set of discrete values. Hash partitioning lets you partition based on the return value from a user-defined expression (the result from a stored SQL/PSM function). Key partitioning performs like hash partitioning, but it lets a user select one or more columns from the …

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MySQL Windows DSN

Almost a Ripley’s Believe It or Not. An prior data science student told me that his new IT department setup a Windows component that let him connect his Excel Spreadsheets to their production MySQL database without a password. Intrigued, I asked if it was a MySQL Connector/ODBC Data Source Configuration, or DSN (Data Source Name)?

He wasn’t sure, so I asked him to connect to PowerShell and run the following command:


It returned something like this (substituting output from one of my test systems):


Name                           Property
----                           --------
MySQL                          Driver      : C:\Program Files\MySQL\Connector ODBC 8.0\myodbc8w.dll
                               DESCRIPTION : MySQL ODBC Connector
                               SERVER      : …
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Setting SQL_MODE

In MySQL, the @@sql_mode parameter should generally use ONLY_FULL_GROUP_BY. If it doesn’t include it and you don’t have the ability to change the database parameters, you can use a MySQL PSM (Persistent Stored Module), like:

Create the set_full_group_by procedure:

-- Drop procedure conditionally on whether it exists already.
DROP PROCEDURE IF EXISTS set_full_group_by;

-- Reset delimter to allow semicolons to terminate statements.

-- Create a procedure to verify and set connection parameter.
CREATE PROCEDURE set_full_group_by()
  COMMENT 'Set connection parameter when not set.'

  /* Check whether full group by is set in the connection and
     if unset, set it in the scope of the connection. */
  END IF; …
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MySQL sakila Database

While I thought my instructions were clear, it appears there should have been more in my examples for using the MySQL MSI. A key thing that happened is that students opted not to install:

Samples and Examples 8.0.22

Unfortunately, they may not have read the Preface of Alan Beaulieu’s Learning SQL, 3rd Edition where he explains how to manually download the files from the MySQL web site. Here are those, very clear, instructions (pg. XV) with my additions in italics for the MySQL Shell:

First, you will need to launch the mysql command-line client or the mysqlsh command-line shell, and provide a password, and then perform the following steps:

  1. Go to and download the files for the …
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