MacLochlainns Weblog

My students wanted an illustration of where MySQL Workbench fits within the MySQL database. So, I overlaid it in this drawing from my old book on comparative SQL syntax for Oracle and MySQL. Anybody else have a cool alternative illustration?

The idea is the lightening bolt transmits an interactive call and reading a script file submits a call paradigm.

More or less MySQL processes a static query in the panel, like the following Python program process the dynamic query (on lines 71-78) with parameters sent when calling the Python script.

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#!/usr/bin/python
# ------------------------------------------------------------
#  Name: mysql-query2.py
#  Date: 20 Aug 2019
# ------------------------------------------------------------
#  Purpose:
#  -------
#    The program shows you how to provide agruments, convert
#    from a list to individual variables of the date type.
#
#    You can call the program:
#
#    ./mysql-query3.py 2001-01-01 2003-12-31
#
# ------------------------------------------------------------
 
# Import the library.
import sys
import mysql.connector
from datetime import datetime
from datetime import date
from mysql.connector import errorcode
 
# Capture argument list.
fullCmdArguments = sys.argv
 
# Assignable variables.
start_date = ""
end_date = ""
 
# Assign argument list to variable.
argumentList = fullCmdArguments[1:]
 
#  Check and process argument list.
# ============================================================
#  If there are less than two arguments provide default values.
#  Else enumerate and convert strings to dates.
# ============================================================
if (len(argumentList) < 2):
  # Set a default start date.
  if (isinstance(start_date,str)):
    start_date = date(1980, 1, 1)
 
  # Set the default end date.
  if (isinstance(end_date,str)):
    end_date = datetime.date(datetime.today())
else:
  # Enumerate through the argument list where beginDate precedes endDate as strings.
  try:
    for i, s in enumerate(argumentList):
      if (i == 0):
        start_date = datetime.date(datetime.fromisoformat(s))
      elif (i == 1):
        end_date = datetime.date(datetime.fromisoformat(s))
  except ValueError:
    print("One of the first two arguments is not a valid date (YYYY-MM-DD).")
 
#  Attempt the query.
# ============================================================
#  Use a try-catch block to manage the connection.
# ============================================================
try:
  # Open connection.
  cnx = mysql.connector.connect(user='student', password='student',
                                host='127.0.0.1',
                                database='studentdb')
  # Create cursor.
  cursor = cnx.cursor()
 
  # Set the query statement.
  query = ("SELECT CASE "
           "         WHEN item_subtitle IS NULL THEN CONCAT('''',item_title,'''') "
           "         ELSE CONCAT('''',item_title,': ',item_subtitle,'''') "
           "         END AS title, "
           "release_date "
           "FROM item "
           "WHERE release_date BETWEEN %s AND %s "
           "ORDER BY item_title")
 
  # Execute cursor.
  cursor.execute(query, (start_date, end_date))
 
  # Display the rows returned by the query.
  for (title, release_date) in cursor:
    print("{}, {:%d-%b-%Y}".format(title, release_date))
 
  # Close cursor.
  cursor.close()
 
# ------------------------------------------------------------
# Handle exception and close connection.
except mysql.connector.Error as e:
  if e.errno == errorcode.ER_ACCESS_DENIED_ERROR:
    print("Something is wrong with your user name or password")
  elif e.errno == errorcode.ER_BAD_DB_ERROR:
    print("Database does not exist")
  else:
    print("Error code:", e.errno)        # error number
    print("SQLSTATE value:", e.sqlstate) # SQLSTATE value
    print("Error message:", e.msg)       # error message
 
# Close the connection when the try block completes.
else:
  cnx.close()

You could call this type of script from the Linux CLI (Command-Line Interface), like this:

./mysql-query3.py '2003-01-01' '2003-12-31' 2>/dev/null

As always, I hope this helps those looking to understand things.

Here’s a quick catalog for my students of PowerShell, JavaScript, and Python examples connecting to MySQL:

• MySQL Powershell Connection with .Net Library Example
• MySQL Powershell Connection with ODBC DSN Example
• MySQL Powershell with CSV File Write Example
• MySQL Powershell with Dialog for Dynamic Connection Inputs
• MySQL Node.js Introduction without Bind Variables
• MySQL Express.js Introcution with Bind Variables – Inclusive of Alternate Syntax
• MySQL Node.js Server-side Scripting Example – Inclusive of Regular Expressions and Parameter Validation
• MySQL Node.js Server-side Clarification of JavaScript Streams
• MySQL Python Connector – Working Example with Python 2 & 3
• MySQL Python with CTE Examples
• MySQL How to use Python to Read a CSV and Write it to a Table
• MySQL How to use Python to cleanup JSON Presentation

As always, I hope this helps those looking for a code sample.

Fresh install of Ubuntu on my MacBook Pro i7 because Apple said the OS X was no longer upgradable. Time to install and configure MySQL Server. These are the steps to install MySQL on the Ubuntu Desktop.

Installation

1. Update the Ubuntu OS by checking for, inspecting, and upgrading any available updates with the following commands:

   sudo apt update sudo apt list sudo apt upgrade

   sudo apt update sudo apt list sudo apt upgrade

2. Check for available MySQL Server packages with this command:

   apt-cache search binaries | grep -i mysql

   apt-cache search binaries | grep -i mysql

   It should return:

   mysql-server - MySQL database server binaries and system database setup mysql-server-8.0 - MySQL database server binaries and system database setup mysql-server-core-8.0 - MySQL database server binaries default-mysql-server - MySQL database server binaries and system database setup (metapackage) default-mysql-server-core - MySQL database server binaries (metapackage) mariadb-server-10.6 - MariaDB database core server binaries mariadb-server-core-10.6 - MariaDB database core server files

   mysql-server - MySQL database server binaries and system database setup mysql-server-8.0 - MySQL database server binaries and system database setup mysql-server-core-8.0 - MySQL database server binaries default-mysql-server - MySQL database server binaries and system database setup (metapackage) default-mysql-server-core - MySQL database server binaries (metapackage) mariadb-server-10.6 - MariaDB database core server binaries mariadb-server-core-10.6 - MariaDB database core server files

3. Check for more details on the MySQL packages with this command:

   apt info -a mysql-server-8.0

   apt info -a mysql-server-8.0

4. Install MySQL Server packages with this command:

   sudo apt install mysql-server-8.0

   sudo apt install mysql-server-8.0

5. Start the MySQL Server service with this command:

   sudo systemctl start mysql.service

   sudo systemctl start mysql.service

6. Before you can run the mysql_secure_installation script, you must set the root password. If you skip this step the mysql_secure_installation script will enter an infinite loop and lock your terminal session. Log in to the mysql monitor with the following command:

   sudo mysql

   sudo mysql

   Enter a password with the following command (password is an insecure example):

   ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'C4nGet1n!';

   ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'C4nGet1n!';

   Quit the mysql monitor session:

   quit;

   quit;

7. Run the mysql_secure_installation script with this command:

   sudo mysql_secure_installation

   sudo mysql_secure_installation

   Here’s the typical output from running the mysql_secure_installation script:

   Securing the MySQL server deployment.   Enter password for user root:   VALIDATE PASSWORD COMPONENT can be used to test passwords and improve security. It checks the strength of password and allows the users to set only those passwords which are secure enough. Would you like to setup VALIDATE PASSWORD component?   Press y|Y for Yes, any other key for No: Y   There are three levels of password validation policy:   LOW Length >= 8 MEDIUM Length >= 8, numeric, mixed case, and special characters STRONG Length >= 8, numeric, mixed case, special characters and dictionary file   Please enter 0 = LOW, 1 = MEDIUM and 2 = STRONG: 2 Using existing password for root.   Estimated strength of the password: 100 Change the password for root ? ((Press y|Y for Yes, any other key for No) : N   ... skipping. By default, a MySQL installation has an anonymous user, allowing anyone to log into MySQL without having to have a user account created for them. This is intended only for testing, and to make the installation go a bit smoother. You should remove them before moving into a production environment.   Remove anonymous users? (Press y|Y for Yes, any other key for No) : Y Success.   Normally, root should only be allowed to connect from 'localhost'. This ensures that someone cannot guess at the root password from the network.   Disallow root login remotely? (Press y|Y for Yes, any other key for No) : Y Success.   By default, MySQL comes with a database named 'test' that anyone can access. This is also intended only for testing, and should be removed before moving into a production environment.     Remove test database and access to it? (Press y|Y for Yes, any other key for No) : Y - Dropping test database... Success.   - Removing privileges on test database... Success.   Reloading the privilege tables will ensure that all changes made so far will take effect immediately.   Reload privilege tables now? (Press y|Y for Yes, any other key for No) : Y Success.   All done!

   Securing the MySQL server deployment. Enter password for user root: VALIDATE PASSWORD COMPONENT can be used to test passwords and improve security. It checks the strength of password and allows the users to set only those passwords which are secure enough. Would you like to setup VALIDATE PASSWORD component? Press y|Y for Yes, any other key for No: Y There are three levels of password validation policy: LOW Length >= 8 MEDIUM Length >= 8, numeric, mixed case, and special characters STRONG Length >= 8, numeric, mixed case, special characters and dictionary file Please enter 0 = LOW, 1 = MEDIUM and 2 = STRONG: 2 Using existing password for root. Estimated strength of the password: 100 Change the password for root ? ((Press y|Y for Yes, any other key for No) : N ... skipping. By default, a MySQL installation has an anonymous user, allowing anyone to log into MySQL without having to have a user account created for them. This is intended only for testing, and to make the installation go a bit smoother. You should remove them before moving into a production environment. Remove anonymous users? (Press y|Y for Yes, any other key for No) : Y Success. Normally, root should only be allowed to connect from 'localhost'. This ensures that someone cannot guess at the root password from the network. Disallow root login remotely? (Press y|Y for Yes, any other key for No) : Y Success. By default, MySQL comes with a database named 'test' that anyone can access. This is also intended only for testing, and should be removed before moving into a production environment. Remove test database and access to it? (Press y|Y for Yes, any other key for No) : Y - Dropping test database... Success. - Removing privileges on test database... Success. Reloading the privilege tables will ensure that all changes made so far will take effect immediately. Reload privilege tables now? (Press y|Y for Yes, any other key for No) : Y Success. All done!

Configuration

The next step is configuration. It requires setting up the sample sakila and studentdb database. The syntax has changed from prior releases. Here are the new three steps:

1. Grant the root user the privilege to grant to others, which root does not have by default. You use the following syntax as the MySQL root user:

   mysql> GRANT ALL ON *.* TO 'root'@'localhost';

   mysql> GRANT ALL ON *.* TO 'root'@'localhost';

2. Download the sakila database, which you can download from this site. Click on the sakila database’s TGZ download.

   

   When you download the sakila zip file it creates a sakila-db folder in the /home/student/Downloads directory. Copy the sakila-db folder into the /home/student/Data/sakila directory. Then, change to the /home/student/Data/sakila/sakila-db directory, connect to mysql as the root user, and run the following command:

   mysql> SOURCE /home/student/Data/sakila/sakila-db/sakila-schema.sql mysql> SOURCE /home/student/Data/sakila/sakila-db/sakila-data.sql

   mysql> SOURCE /home/student/Data/sakila/sakila-db/sakila-schema.sql mysql> SOURCE /home/student/Data/sakila/sakila-db/sakila-data.sql

3. Create the studentdb database with the following command as the MySQL root user:

   mysql> CREATE DATABASE studentdb;

   mysql> CREATE DATABASE studentdb;

4. Create the user with a clear English password and grant the user student full privileges on the sakila and studentdb databases:

   mysql> CREATE USER 'student'@'localhost' IDENTIFIED WITH mysql_native_password BY 'Stud3nt!'; mysql> GRANT ALL ON studentdb.* TO 'student'@'localhost'; mysql> GRANT ALL ON sakila.* TO 'student'@'localhost';

   mysql> CREATE USER 'student'@'localhost' IDENTIFIED WITH mysql_native_password BY 'Stud3nt!'; mysql> GRANT ALL ON studentdb.* TO 'student'@'localhost'; mysql> GRANT ALL ON sakila.* TO 'student'@'localhost';

You can now connect to a sandboxed sakila database with the student user’s credentials, like:

mysql -ustudent -p -Dsakila

or, you can now connect to a sandboxed studentdb database with the student user’s credentials, like:

mysql -ustudent -p -Dstudentdb

MySQL Workbench Installation

sudo snap install mysql-workbench-community

You have now configure the MySQL Server 8.0.

Having configured an AlmaLinux 8.6 with Oracle Database 11g XE, MySQL 8.0.30, and PostgreSQL 15, we migrated it to AWS EC2 and provisioned it. We used the older and de-supported Oracle Database 11g XE because it didn’t require any kernel modifications and had a much smaller footprint.

I had to address why attempting to connect with the sqlplus utility raised the following error after provisioning a copy with a new static IP address:

ERROR:
ORA-12514: TNS:listener does NOT currently know OF service requested IN CONNECT descriptor

A connection from SQL Developer raises a more addressable error, like:

ORA-17069

I immediately tried to check the connection with the tnsping utility and found that tnsping worked fine. However, when I tried to connect with the sqlplus utility it raised an ORA-12514 connection error.

There were no diagnostic steps beyond checking the tnsping utility. So, I had to experiment with what might block communication.

I changed the host name from ip-172-58-65-82.us-west-2.compute.internal to a localhost string in both the listener.ora and tnsnames.ora. The listener.ora file:

# listener.ora Network Configuration FILE:
 
SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = /u01/app/oracle/product/11.2.0/xe)
      (PROGRAM = extproc)
    )
  )
 
LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_XE))
      (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
    )
  )
 
DEFAULT_SERVICE_LISTENER = (XE)

The tnsnames.ora file:

# tnsnames.ora Network Configuration FILE:
 
XE =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = XE)
    )
  )
 
EXTPROC_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_XE))
    )
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
    )
  )

I suspected that it might be related to the localhost value. So, I checked the /etc/hostname and /etc/hosts files.

Then, I modified /etc/hostname file by removing the AWS EC2 damain address. I did it on a memory that Oracle’s TNS raises errors for dots or periods in some addresses.

The /etc/hostname file:

ip-172-58-65-82

The /etc/hosts file:

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4 ip-172-58-65-82
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6 ip-172-58-65-82

Now, we can connect to the Oracle Database 11g XE instance with the sqlplus utility. I believe this type of solution will work for other AWS EC2 provisioned Oracle databases.

Installing MySQL Workbench 8 on Windows, we discovered that the default configuration no longer sets ONLY_FULL_GROUP_BY as part of the default SQL_MODE parameter value. While I’ve written a stored function to set the SQL_MODE parameter value for a session, some students didn’t understand that such a call is only valid in the scope of a connection to the database server. They felt the function didn’t work because they didn’t understand the difference between connecting to the MySQL CLI and clicking the lightening bolt in MySQL Workbench.

So, here are the instructions to reset the default SQL_MODE parameter value for Windows. You need to edit the setting in the my.ini file, which is in the C:\ProgramData\MySQL\MySQL Server 8.0 directory. The default installation will have the following:

# Set the SQL mode to strict
sql-mode="STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION"

You need to change it to the following in an editor with Administrative privileges:

# Set the SQL mode to strict
sql-mode="STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION,ONLY_FULL_GROUP_BY"

Then, you need to connect to the services by launching services.msc from the command prompt. In the list of services find MYSQL80 service and restart it. You can verify it by connecting to the MySQL 8.0.* server and running the following SQL query:

SELECT @@SQL_MODE:

That’s how you convert Windows to use only traditional group by behaviors in SQL. As always, I hope this helps those looking for a solution.

I discovered a dependency for MySQL Workbench on AlmaLinux 8 installation. I neglected to fully cover it when I documented the installation in a VM of AlmaLinux 9. I go back later and update that entry but for now you need the following dependencies:

proj-6.3.2-4.el8.x86_64.rpm
proj-datumgrid-1.8-6.3.2.4.el8.noarch.rpm
proj-devel-6.3.2-4.el8.x86_64.rpm

Install like this:

sudo dnf install -y *.rpm

Log file:

Last metadata expiration check: 3:01:53 ago on Fri 10 Feb 2023 03:37:49 AM UTC.
Dependencies resolved.
==========================================================================================
 Package                Architecture   Version                 Repository            Size
==========================================================================================
Installing:
 proj                   x86_64         6.3.2-4.el8             @commandline         2.0 M
 proj-datumgrid         noarch         1.8-6.3.2.4.el8         @commandline         5.4 M
 proj-devel             x86_64         6.3.2-4.el8             @commandline          89 k
 
Transaction Summary
==========================================================================================
Install  3 Packages
 
Total size: 7.5 M
Installed size: 17 M
Downloading Packages:
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                                  1/1 
  Installing       : proj-datumgrid-1.8-6.3.2.4.el8.noarch                            1/3 
  Installing       : proj-6.3.2-4.el8.x86_64                                          2/3 
  Installing       : proj-devel-6.3.2-4.el8.x86_64                                    3/3 
  Running scriptlet: proj-devel-6.3.2-4.el8.x86_64                                    3/3 
  Verifying        : proj-6.3.2-4.el8.x86_64                                          1/3 
  Verifying        : proj-datumgrid-1.8-6.3.2.4.el8.noarch                            2/3 
  Verifying        : proj-devel-6.3.2-4.el8.x86_64                                    3/3 
 
Installed:
  proj-6.3.2-4.el8.x86_64                 proj-datumgrid-1.8-6.3.2.4.el8.noarch          
  proj-devel-6.3.2-4.el8.x86_64          
 
Complete!

A quick update while installing AlmaLinux for AWS.

This is an update for MySQL 8 Stored PSM to add the ONLY_FULL_GROUP_BY mode to the global SQL_MODE variable when it’s not set during a session. Here’s the code:

/* Drop procedure conditionally on whether it exists already. */
DROP PROCEDURE IF EXISTS set_full_group_by;
 
/* Reset delimter to allow semicolons to terminate statements. */
DELIMITER $$
 
/* Create a procedure to verify and set connection parameter. */
CREATE PROCEDURE set_full_group_by()
  LANGUAGE SQL
  NOT DETERMINISTIC
  SQL SECURITY DEFINER
  COMMENT 'Set connection parameter when not set.'
BEGIN
 
  /* Check whether full group by is set in the connection and
     if unset, set it in the scope of the connection. */
  IF EXISTS
    (SELECT TRUE
     WHERE NOT REGEXP_LIKE(@@SESSION.SQL_MODE,'ONLY_FULL_GROUP_BY'))
  THEN
    SET @@GLOBAL.SQL_MODE := CONCAT(@@SESSION.sql_mode,',ONLY_FULL_GROUP_BY');
  END IF;
END;
$$
 
/* Reset the default delimiter. */
DELIMITER ;

You can call the set_full_group_by procedure with the CALL command:

CALL set_full_group_by();

You can see the SQL_MODE variable with the following query:

SELECT @@GLOBAL.SQL_MODE;

It’ll return:

+---------------------------------------------------------------+
| @@GLOBAL.SQL_MODE                                             |
+---------------------------------------------------------------+
| ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION |
+---------------------------------------------------------------+
1 row in set (0.00 sec)

As always, I hope this helps those looking to solve this type of problem.

It’s always interesting to see how others teach SQL courses. It can be revealing as to whether they understand SQL or only understand a dialect of SQL. In this case, one of my old students was taking a graduate course in SQL and the teacher was using MySQL. The teacher made an issue of using ANSI SQL:1999 or SQL3 and asked the following question, which I suspect is a quiz bank question from a textbook:

“How would you get all students’ names and for each student the number of courses that the
student has registered for?”

They referenced the MySQL 5.7 documentation for the GROUP BY and SQL:1999 as if MySQL implemented the ANSI SQL:1999 specification defined the standard. I didn’t know whether to laugh or cry because they were referring to MySQL 5.7 when we’re all using MySQL 8 and anybody who’s worked in more than MySQL knows that the behavior for a GROUP BY in MySQL can work without listing the necessary non-aggregated columns in the SELECT-list.

For example, their working solution, which is from the instructor and the author of their MySQL textbook the correct perspective of ANSI:1999 behavior. It doesn’t matter that their solution is actually based on ANSI:1992 not ANSI:1999 because it will only succeed because of a quirk of MySQL:

SELECT   a.studentname
,        COUNT(b.courseid)
FROM     students a INNER JOIN registeredcourses b
ON       a.studentid = b.studentid
GROUP BY a.studentid;

While it works in MySQL, it doesn’t work because it conforms to an ANSI standard. It works in MySQL, notwithstanding that standard because it violates the standard.

In Oracle, PostgreSQL, and SQL Server, it raises an exception. For example, Oracle raises the following exception:

SELECT   a.studentname
         *
ERROR at line 1:
ORA-00979: not a GROUP BY expression

The correct way to write the GROUP BY is:

SELECT   a.studentname
,        COUNT(b.courseid)
FROM     students a INNER JOIN registeredcourses b
ON       a.studentid = b.studentid INNER JOIN courses c
ON       b.courseid = c.courseid
GROUP BY a.studentname;

Then, it would return:

Student Name                   Course IDs
------------------------------ ----------
Montgomery Scott                        1
Leonard McCoy                           2
James Tiberus Kirk                      3

For reference, here’s a complete test case for MySQL:

/* Drop table conditionally. */
DROP TABLE IF EXISTS students;
 
/* Create table. */
CREATE TABLE students
( studentID    int unsigned primary key auto_increment
, studentName  varchar(30));
 
/* Drop table conditionally. */
DROP TABLE IF EXISTS courses;
 
/* Create table. */
CREATE TABLE courses
( courseid    int unsigned primary key auto_increment
, coursename  varchar(40));
 
/* Drop table conditionally. */
DROP TABLE IF EXISTS registeredcourses;
 
/* Create table. */
CREATE TABLE registeredcourses
( courseid    int unsigned
, studentid   int unsigned );
 
/* Insert into students. */
INSERT INTO students
( studentName )
VALUES
 ('James Tiberus Kirk')
,('Leonard McCoy')
,('Montgomery Scott');
 
/* Insert into courses. */
INSERT INTO courses
( coursename )
VALUES
 ('English Literature')
,('Physics')
,('English Composition')
,('Botany')
,('Mechanical Engineering');
 
/* Insert into registeredcourses. */
INSERT INTO registeredcourses
( studentid
, courseid )
VALUES
 (1,1)
,(1,3)
,(1,4)
,(2,2)
,(2,5)
,(3,4); 
 
/* Check global sql_mode to ensure only_full_group_by is set. */
SELECT @@GLOBAL.SQL_MODE;
 
/* Query with a column not found in the SELECT-list. */
SELECT   a.studentname
,        COUNT(b.courseid)
FROM     students a INNER JOIN registeredcourses b
ON       a.studentid = b.studentid
GROUP BY a.studentid;
 
/* Query consistent with ANSI SQL:1992 */
SELECT   a.studentname
,        COUNT(b.courseid)
FROM     students a INNER JOIN registeredcourses b
ON       a.studentid = b.studentid INNER JOIN courses c
ON       b.courseid = c.courseid
GROUP BY a.studentname;

and, another complete test case for Oracle:

/* Drop tabhe unconditionallly. */
DROP TABLE students;
 
/* Create table. */
CREATE TABLE students
( studentID    NUMBER PRIMARY KEY
, studentName  VARCHAR(30));
 
/* Drop table unconditionally. */
DROP TABLE courses;
 
/* Create table. */
CREATE TABLE courses
( courseid    NUMBER PRIMARY KEY
, coursename  VARCHAR(40));
 
/* Drop table unconditionally. */
DROP TABLE registeredcourses;
 
/* Create table. */
CREATE TABLE registeredcourses
( courseid    NUMBER
, studentid   NUMBER );
 
/* Insert values in student. */
INSERT INTO students ( studentid, studentName ) VALUES (1,'James Tiberus Kirk');
INSERT INTO students ( studentid, studentName ) VALUES (2,'Leonard McCoy');
INSERT INTO students ( studentid, studentName ) VALUES (3,'Montgomery Scott');
 
/* Insert values in courses. */
INSERT INTO courses ( courseid, coursename ) VALUES (1,'English Literature');
INSERT INTO courses ( courseid, coursename ) VALUES (2,'Physics');
INSERT INTO courses ( courseid, coursename ) VALUES (3,'English Composition');
INSERT INTO courses ( courseid, coursename ) VALUES (4,'Botany');
INSERT INTO courses ( courseid, coursename ) VALUES (5,'Mechanical Engineering');
 
/* Insert values into registeredcourses. */
INSERT INTO registeredcourses ( studentid, courseid ) VALUES (1,1);
INSERT INTO registeredcourses ( studentid, courseid ) VALUES (1,3);
INSERT INTO registeredcourses ( studentid, courseid ) VALUES (1,4);
INSERT INTO registeredcourses ( studentid, courseid ) VALUES (2,2);
INSERT INTO registeredcourses ( studentid, courseid ) VALUES (2,5);
INSERT INTO registeredcourses ( studentid, courseid ) VALUES (3,4); 
 
/* Non-ANSI SQL GROUP BY statement. */
SELECT   a.studentname
,        COUNT(b.courseid)
FROM     students a INNER JOIN registeredcourses b
ON       a.studentid = b.studentid
GROUP BY a.studentid;
 
/* ANSI SQL GROUP BY statement. */
SELECT   a.studentname AS "Student Name"
,        COUNT(b.courseid) AS "Course IDs"
FROM     students a INNER JOIN registeredcourses b
ON       a.studentid = b.studentid INNER JOIN courses c
ON       b.courseid = c.courseid
GROUP BY a.studentname;

I hope this helps those learning the correct way to write SQL.

LAMP (Linux, Apache, MySQL, Perl/PHP/Python) Architecture is very flexible. All the components can be positioned on the same server or different servers. The servers are divided into two types. The types are known as the Application or database tiers. Generally, the application tier holds the Apache Server, any Apache Modules, and local copies of Server Side Includes (SSI) programs.

In many development environments, you also deploy the client to the same machine. This means a single machine runs the database server, the application server, and the browser. The lab for this section assumes these configurations.

Before you test an installation, you should make sure that you’ve started the database and Apache server. In an Oracle LAMP configuration (known as an OLAP – Oracle, Linux, Apache, Perl/PHP/Python), you must start both the Oracle Listener and database. MySQL starts the listener when you start the database. You must also start the Apache Server. The Apache Server also starts an Apache Listener, which listens for incoming HTTP/HTTPS requests. It listens on Port 80 unless you override that setting in the httpd.conf file.

The URI reaches the server and is redirected to an Apache Module based on configuration information found in the httpd.conf file. Spawned or child processes of the Apache Module then read programs into memory from the file system and run them. If you’ve uploaded a file the locally stored program can move it from a secure cache location to another local area for processing. The started programs can run independently or include other files as libraries, and they can communicate to the database server.

Working though PHP test cases against the MySQL database for my AlmaLinux installation and configuration, I discovered that the php-gd library weren’t installed by default. I had to add it to get my PHP programs to upload and display PNG files.

The log file for applying the php-gd packages:

Last metadata expiration check: 3:59:15 ago on Wed 28 Dec 2022 08:17:58 PM EST.
Dependencies resolved.
================================================================================
 Package         Architecture    Version               Repository          Size
================================================================================
Installing:
 php-gd          x86_64          8.0.20-3.el9          appstream           43 k
 
Transaction Summary
================================================================================
Install  1 Package
 
Total download size: 43 k
Installed size: 110 k
Downloading Packages:
php-gd-8.0.20-3.el9.x86_64.rpm                  196 kB/s |  43 kB     00:00    
--------------------------------------------------------------------------------
Total                                            39 kB/s |  43 kB     00:01     
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                        1/1 
  Installing       : php-gd-8.0.20-3.el9.x86_64                             1/1 
  Running scriptlet: php-gd-8.0.20-3.el9.x86_64                             1/1 
  Verifying        : php-gd-8.0.20-3.el9.x86_64                             1/1 
 
Installed:
  php-gd-8.0.20-3.el9.x86_64                                                    
 
Complete!

The balance of this page demonstrates how to upload, store, and manage Text (Character Large Data Streams) and BLOBs (Binary Large Objects). It provides MySQL equivalent instructions to those for manaing LOBs in an Oracle database. As covered in Chapter 8 in my Oracle Database 11g PL/SQL Programming book.

Before you begin these steps, you should have already installed Zend Server Community Edition. If you haven’t done so, please click here for instructions.

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<?php
  // Connection variables.
  define('HOSTNAME',"localhost");
  define('USERNAME',"student");
  define('PASSWORD',"student");
  define('DATABASE',"sampledb");
?>

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<html>
<head>
<title>
  UploadItemDescMySQLForm.htm
</title>
</head>
<body>
<form id="uploadForm"
      action="UploadItemDescMySQL.php"
      enctype="multipart/form-data"
      method="post">
  <table border=0 cellpadding=0 cellspacing=0>
    <tr>
      <td width=125>Item Number</td>
      <td>
        <input id="id" name="id" type="text">
      </td>
    </tr>
    <tr>
      <td width=125>Item Title</td>
      <td>
        <input id="title" name="title" type="text">
      </td>
    </tr>
    <tr>
      <td width=125>Select File</td>
      <td>
        <input id="uploadfilename" name="userfile" type="file">
      </td>
    </tr>
    <tr>
      <td width=125>Click Button to</td>
      <td><input type="submit" value="Upload File"></td>
    </tr>
  </table>
</form>
</body>
</html>

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<?php
  // Set database credentials.
  include_once("MySQLCredentials.inc");
 
  // Displayed moved file in web page.
  $item_desc = process_uploaded_file();
 
  // Return successful attempt to connect to the database.
  if (!$c = @mysqli_connect(HOSTNAME,USERNAME,PASSWORD,DATABASE)) {
    // Print user message.
    print "Sorry! The connection to the database failed. Please try again later.";
 
    // Assign the mysqli_error() and format double and single quotes.
    print mysqli_error();
 
    // Kill the resource.
    die();
  }
  else {
    // Declare input variables.
    $id = (isset($_POST['id']))    ? (int) $_POST['id'] : $id = 21;
    $title = (isset($_POST['title'])) ? $_POST['title'] : $title = "Harry #1";
 
    // Initialize a statement in the scope of the connection.
    $stmt = mysqli_stmt_init($c);
 
    // Declare a PL/SQL execution command.
    $sql = "Update item  set item_desc = ? where item_id = ?";
 
    // Prepate statement and link it to a connection.
    if (mysqli_stmt_prepare($stmt,$sql)) {
      mysqli_stmt_bind_param($stmt,"si",$item_desc,$id);
 
      // Execute it and print success or failure message.
      if (mysqli_stmt_execute($stmt)) {
        query_insert($id,$title);
      }
      else {
        print "You're target row doesn't exist.";
      }
    }
    // Disconnect from database.
    mysqli_close($c);
  }
 
  // Query results afret an insert.
  function query_insert($id,$title)
  {
    // Return successful attempt to connect to the database.
    if (!$c  = @mysqli_connect(HOSTNAME,USERNAME,PASSWORD,DATABASE)) {
      // Print user message.
      print "Sorry! The connection to the database failed. Please try again later.";
 
      // Assign the OCI error and format double and single quotes.
      print mysqli_error();
 
      // Kill the resource.
      die();
    }
    else {
 
      // Initialize a statement in the scope of the connection.
      $stmt = mysqli_stmt_init($c);
 
      // Declare a SQL SELECT statement returning a CLOB.
      $sql = "SELECT item_desc FROM item WHERE item_id = ?";
 
      // Prepare statement.
      if (mysqli_stmt_prepare($stmt,$sql)) {
        mysqli_stmt_bind_param($stmt,"i",$id);
 
        // Execute it and print success or failure message.
        if (mysqli_stmt_execute($stmt)) {
 
          // Bind result to local variable.
	      mysqli_stmt_bind_result($stmt, $desc);
 
          // Read result.
          mysqli_stmt_fetch($stmt);
 
          // Format HTML table to display biography.
          $out = '<table border="1" cellpadding="3" cellspacing="0">';
          $out .= '<tr>';
          $out .= '<td align="center" class="e">'.$title.'</td>';
          $out .= '</tr>';
          $out .= '<tr>';
          $out .= '<td class="v">'.$desc.'</td>';
          $out .= '</tr>';
          $out .= '</table>';
 
          // Print the HTML table.
          print $out;
        }
      }
 
      // Disconnect from database.
      mysqli_close($c);
    }
  }
 
  // Manage file upload and return file as string.
  function process_uploaded_file()
  {
    // Declare a variable for file contents.
    $contents = "";
 
    // Define the upload file name for Windows or Linux.
    if (preg_match(".Win32.",$_SERVER["SERVER_SOFTWARE"]))
      $upload_file = "C:\\temp\\".$_FILES['userfile']['name'];
    else
      $upload_file = "/tmp/".$_FILES['userfile']['name'];
 
    // Check for and move uploaded file.
    if (is_uploaded_file($_FILES['userfile']['tmp_name']))
      move_uploaded_file($_FILES['userfile']['tmp_name'],$upload_file);
 
    // Open a file handle and suppress an error for a missing file.
    if ($fp = @fopen($upload_file,"r"))
    {
      // Read until the end-of-file marker.
      while (!feof($fp))
        $contents .= fgetc($fp);
      // Close an open file handle.
      fclose($fp);
    }
    // Return file content as string.
    return $contents;
  }
?>

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<?php
  // Connection variables.
  define('HOSTNAME',"localhost");
  define('USERNAME',"student");
  define('PASSWORD',"student");
  define('DATABASE',"sampledb");
?>

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<html>
<head>
<title>
  UploadItemBlobMySQLForm.htm
</title>
</head>
<body>
<form id="uploadForm"
      action="UploadItemBlobMySQL.php"
      enctype="multipart/form-data"
      method="post">
  <table border=0 cellpadding=0 cellspacing=0>
    <tr>
      <td width=125>Item Number</td>
      <td>
        <input id="id" name="id" type="text">
      </td>
    </tr>
    <tr>
      <td width=125>Item Title</td>
      <td>
        <input id="title" name="title" type="text">
      </td>
    </tr>
    <tr>
      <td width=125>Select File</td>
      <td>
        <input id="uploadfilename" name="userfile" type="file">
      </td>
    </tr>
    <tr>
      <td width=125>Click Button to</td>
      <td><input type="submit" value="Upload File"></td>
    </tr>
  </table>
</form>
</body>
</html>

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<?php
  // Set database credentials.
  include_once("MySQLCredentials.inc");
 
  // Displayed moved file in web page.
  $item_blob = process_uploaded_file();
 
  // Return successful attempt to connect to the database.
  if (!$c = @mysqli_connect(HOSTNAME,USERNAME,PASSWORD,DATABASE)) {
    // Print user message.
    print "Sorry! The connection to the database failed. Please try again later.";
 
    // Assign the mysqli_error() error and format double and single quotes.
    print mysqli_error();
 
    // Kill the resource.
    die();
  }
  else {
    // Declare input variables.
    $id = (isset($_POST['id'])) ? (int) $_POST['id'] : 1021;
    $title = (isset($_POST['title'])) ? $_POST['title'] : "Harry #1";
 
    // Initialize a statement in the scope of the connection.
    $stmt = mysqli_stmt_init($c);
 
   // Declare a PL/SQL execution command.
    $sql = "UPDATE item SET item_blob = ? WHERE item_id =  ?";
 
    // Prepare statement and link it to a connection.
    if (mysqli_stmt_prepare($stmt,$sql)) {
      mysqli_stmt_bind_param($stmt,"bi",$item_blob,$id);
 
      $start = 0;
      $chunk = 8192;
      while ($start < strlen($item_blob)) {
        mysqli_stmt_send_long_data($stmt,0,substr($item_blob,$start,$chunk));
        $start += $chunk;
      }
 
      // Execute the PL/SQL statement.
      if (mysqli_stmt_execute($stmt)) {
        query_insert($id,$title);
      }
      else {
        print "Your target row doesn't exist.";
      }
    }
    else { print "mysqli_stmt_prepare() failed."; }
    // Disconnect from database.
    mysqli_close($c);
  }
 
  // Query results afret an insert.
  function query_insert($id,$title)
  {
    // Return successful attempt to connect to the database.
    if (!$c = @mysqli_connect(HOSTNAME,USERNAME,PASSWORD,DATABASE)) {
      // Print user message.
      print "Sorry! The connection to the database failed. Please try again later.";
 
      // Assign the OCI error and format double and single quotes.
      print mysqli_error();
 
      // Kill the resource.
      die();
    }
    else {
 
      // Initialize a statement in the scope of the connection.
      $stmt = mysqli_stmt_init($c);
 
      // Declare a SQL SELECT statement returning a CLOB.
      $sql = "SELECT item_desc FROM item WHERE item_id = ?";
 
      // Prepare statement and link it to a connection.
      if (mysqli_stmt_prepare($stmt,$sql)) {
        mysqli_stmt_bind_param($stmt,"i",$id);
 
        // Execute the PL/SQL statement.
        if (mysqli_stmt_execute($stmt)) {
 
          // Bind result to local variable.
	      mysqli_stmt_bind_result($stmt, $data);
 
          // Read result.
          mysqli_stmt_fetch($stmt);
 
          // Format HTML table to display BLOB photo and CLOB description.
          $out = '<table border="1" cellpadding="5" cellspacing="0">';
          $out .= '<tr>';
          $out .= '<td align="center" class="e">'.$title.'</td>';
          $out .= '</tr>';
          $out .= '<tr><td class="v">';
          $out .= '<div>';
          $out .= '<div style="margin-right:5px;float:left">';
          $out .= '<img src="ConvertMySQLBlobToImage.php?id='.$id.'">';
          $out .= '</div>';
          $out .= '<div style="position=relative;">'.$data.'</div>';
          $out .= '</div>';
          $out .= '</td></tr>';
          $out .= '</table>';
 
          // Print the HTML table.
          print $out;
        }
        else {
          print "You're target row doesn't exist.";
        }
      }
 
      // Disconnect from database.
      mysqli_close($c);
    }
  }
 
  // Manage file upload and return file as string.
  function process_uploaded_file()
  {
    // Declare a variable for file contents.
    $contents = "";
 
    // Define the upload file name for Windows or Linux.
    if (preg_match(".Win32.",$_SERVER["SERVER_SOFTWARE"]))
      $upload_file = "C:\\TEMP\\".$_FILES['userfile']['name'];
    else
      $upload_file = "/tmp/".$_FILES['userfile']['name'];
 
    // Check for and move uploaded file.
    if (is_uploaded_file($_FILES['userfile']['tmp_name']))
      move_uploaded_file($_FILES['userfile']['tmp_name'],$upload_file);
 
    // Open a file handle and suppress an error for a missing file.
    if ($fp = @fopen($upload_file,"r"))
    {
      // Read until the end-of-file marker.
      while (!feof($fp))
        $contents .= fgetc($fp);
 
      // Close an open file handle.
      fclose($fp);
    }
 
    // Return file content as string.
    return $contents;
  }
?>

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<?php
  // Database credentials must be set manually because an include_once() function
  // call puts something ahead of the header, which causes a failure when rendering
  // an image.
 
  // Return successful attempt to connect to the database.
  if (!$c = @mysqli_connect("localhost","student","student","sampledb")) {
 
    // Print user message.
    print "Sorry! The connection to the database failed. Please try again later.";
 
    // Assign the OCI error and format double and single quotes.
    print mysqli_error();
 
    // Kill the resource.
    die();
  }
  else {
 
    // Declare input variables.
    $id = (isset($_GET['id'])) ? (int) $_GET['id'] : 1023;
 
    // Initialize a statement in the scope of the connection.
    $stmt = mysqli_stmt_init($c);
 
    // Declare a SQL SELECT statement returning a MediumBLOB.
    $sql = "SELECT item_blob FROM item WHERE item_id = ?";
 
    // Prepare statement and link it to a connection.
    if (mysqli_stmt_prepare($stmt,$sql)) {
      mysqli_stmt_bind_param($stmt,"i",$id);
 
      // Execute the PL/SQL statement.
      if (mysqli_stmt_execute($stmt)) {
 
        // Bind result to local variable.
	      mysqli_stmt_bind_result($stmt, $image);
 
        // Read result.
        mysqli_stmt_fetch($stmt);
      }
    } 
 
    // Disconnect from database.
    mysqli_close($c);
 
    // Print the header first.
    header('Content-type: image/x-png');
    imagepng(imagecreatefromstring($image));
  }
?>

mysql -ustudent -pstudent

mysql> source /Data/mysql/create_mysql_store.sql
mysql> source /Data/mysql/seed_mysql_store.sql

ALTER TABLE item
ADD (item_desc TEXT, item_blob MEDIUMBLOB);

SELECT   i.item_id
,        length(i.item_desc)
,        length(i.item_blob)
FROM     item i
WHERE    i.item_desc IS NOT NULL
OR       i.item_blob IS NOT NULL;

If you find any problems, please let me know. I’ll be happy to fix them.

This is a collection of blog posts for installing and configuring AlmaLinux with the Oracle, PostgreSQL, MySQL databases and several programming languages. Sample programs show how to connect PHP and Python to the MySQL database.

• Installing AlmaLinux operating system
• Installing and configuring MySQL
• Installing Python-MySQL connector and provide sample programs
• Configuring Flask for Python on AlmaLinux with a complete software router instruction set.
• Installing Rust programming language and writing a sample program
• Installing and configuring LAMP stack with PHP and MySQL and a self-signed security key
• MySQL PNG Images in LAMP with PHP Programming
• Demonstration of how to write Perl that connects to MySQL
• Installing and configuring MySQL Workbench
• Installing and configuring PostgreSQL and pgAdmin4
• Identifying the required libnsl2-devel packages for SQL*Plus
• Writing and deploying a sqlplus function to use a read line wrapper
• Installing and configuring Visual Studio Code Editor
• Installing and configuring Java with connectivity to MySQL
• Installing and configuring Oracle SQL Developer

I used Oracle Database 11g XE in this instance to keep the footprint as small as possible. It required a few tricks and discovering the missing library that caused folks grief eleven years ago. I build another with a current Oracle Database XE after the new year.

If you see something that I missed or you’d like me to add, let me know. As time allows, I’ll try to do that. Naturally, the post will get updates as things are added later.