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MySQL Posts Summary

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

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

Written by maclochlainn

June 16th, 2023 at 12:38 am

Posted in JavaScript,Linux,MySQL,MySQL 8,PowerShell,Python 3.x

Tagged with ,

MySQL on Ubuntu

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

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

    apt info -a mysql-server-8.0
  4. Install MySQL Server packages with this command: 

    sudo apt install mysql-server-8.0
  5. Start the MySQL Server service with this command: 

    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

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

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

    Quit the mysql monitor session:

    quit;
  7. Run the mysql_secure_installation script with this command: 

    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!

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

    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';

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.

Written by maclochlainn

May 23rd, 2023 at 4:18 pm

Posted in LAMP,Linux,MySQL,MySQL 8,MySQL Shell,Unix

Tagged with ,

AWS EC2 TNS Listener

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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.

Written by maclochlainn

March 22nd, 2023 at 10:09 pm

Posted in AlmaLinux,Database,DBA,DevOps,Linux,MySQL 8,Oracle,Oracle 11g,Oracle DBA,sql,SQL Developer,SQL*Plus

MySQL @SQL_MODE

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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.

Written by maclochlainn

February 13th, 2023 at 12:55 pm

Posted in Microsoft Windows 10,Microsoft Windows 11,MySQL,MySQL 8,MySQL Workbench,Windows 10,Windows 11

Tagged with ,

AlmaLinux Libraries

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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.

Written by maclochlainn

February 9th, 2023 at 11:47 pm

Posted in AlmaLinux,MySQL,MySQL 8,MySQL Workbench

Tagged with

Updating SQL_MODE

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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.

Written by maclochlainn

January 13th, 2023 at 12:06 am

Posted in Database,MySQL,MySQL 8,MySQL Shell

Tagged with ,

GROUP BY Quirk

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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.

Written by maclochlainn

January 12th, 2023 at 11:30 pm

Posted in MySQL,MySQL 8,Oracle,Oracle 18c,Oracle 21c,PostgreSQL,PostgreSQL 15,SQL Server,SQL Server 2014

Tagged with , , ,

MySQL PNG Files

with one comment

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:

Display detailed console log →

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.

Create directories or folders, and position code →

This section provides you with instructions on how to position the code components in Windows, at least for the newbie. If you’re on Linux, you probably know how to do most if not all of this already. Likewise, if you already know how to put things in the right place, please choose your own locations.

  1. Create a LOB (Large Object) directory for the PHP files inside the htdocs directory.

oraclelobsetup1

    You can down the MySQL PHP Upload LOB Web Code zip file and unzip it into the directory you just created. It can co-exist with the Oracle equivalent if you’ve done that already.

Load a TEXT (like an Oracle CLOB) column to the MySQL database →

This is a copy of the three files required to load a large string to a MySQL database into a mediumtext data type. The code is in clear text because somebody asked for it. They’re nervous about zip files. Click the title above to expand all the code text.

MySQLCredentials.inc

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

UploadItemDescMySQLForm.htm

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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>

UploadItemDescMySQL.php

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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;
  }
?>

Load a BLOB column to the MySQL database →

This is a copy of the four files required to load a large image to a MySQL database into a MEDIUMBLOB data type. The fourth file reads the binary image and translates it into an HTML header and image that can be read through a call to the src attribute of an img tag. You can find the call to the forth file in the UploadItemBlobMySQL.php.

The code is in clear text because somebody asked for it. They’re nervous about zip files. Click the title above to expand all the code text.

MySQLCredentials.inc

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

UploadItemBlobMySQLForm.htm

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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>

UploadItemBlobMySQL.php

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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;
  }
?>

ConvertMySQLBlobToImage.php

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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));
  }
?>
  1. Create a temp directory for the upload target location, as qualified in the PHP code. The PHP code works regardless of whether you’re on Windows or Linux, but it does depend on the creation of this directory.

oraclelobsetup2

  1. Create a directory or folder for the large file source directories. This directory is probably on your test machine (laptop) but it mimics a client laptop and would work if your server was on a different machine.

oraclelobsetup3

  1. Inside the Upload directory, you should create the following two directories:

oraclelobsetup4

    You should download the CLOB Text File zip file and unzip it into the textfiles directory; then download the BLOB Image File zip file and unzip it into the imagefiles directory.

Assuming you’ve downloaded the zip files and extracted them into the correct locations, this section is done.

Prepare the MySQL database →

This section provides you with instructions on how to ensure everything will work once the PHP programs call the database. Even if you have one of my sample Video Store databases, you should verify and add appropriate columns. This post assumes you’ve downloaded the one of my basic Video Store models

  1. Navigate to the directory that you created for SQL scripts, which should be /home/student/Data/mysql. In that directory at the command prompt, connect as the student user, which should be student. You connect to the MySQL database, with the following syntax as student (if you need more help, check this blog post on configuring MySQL).
mysql -ustudent -pstudent

Once connected to the database, you run the files to create the database, like:

mysql> source /Data/mysql/create_mysql_store.sql
mysql> source /Data/mysql/seed_mysql_store.sql
  1. Navigate to the directory that you created for SQL scripts, which should be /home/student/Data/mysql. In that directory at the command prompt, connect as the student user, or whichever account you’re using. You should confirm that you have a item_desc column of TEXT data type, and an item_blob column of MEDIUMBLOB type in the item table. If you don’t have those columns, you can add them with the following statement:
ALTER TABLE item
ADD (item_desc TEXT, item_blob MEDIUMBLOB);

After ensuring that you have those two columns, you’ve completed this section.

Test the Configuration →

This section shows you how to test all that you’ve done. It works provided you created the directories and extracted the zip file contents to their respective directories. The virtual URL actually maps to the /var/www/html/lob directory.

  1. Enter the http://localhost/lob/UploadItemDescMySQLForm.htm URL, and complete the form by choosing a valid item_id column value and text file from your /home/student/Upload/TextFiles directory. Then, click the Upload File button (you can see a larger version of the image by clicking on it).

mysql_lob1

  1. This page displays after you successfully upload the text file to the database.

mysql_lob2

  1. Enter the http://localhost/lob/UploadItemBlobFormMySQL.htm URL, and complete the form by choosing a valid item_id column value and image file from your /home/student/Upload/ImageFiles directory. Then, click the Upload File button (you can see a larger version of the image by clicking on it).

mysql_lob3

  1. This page displays after you successfully upload the image file to the database.

mysql_lob4

Troubleshooting the Configuration →

This section shows you how to check why something isn’t working.

  1. The first thing to check are the credentials. They’re in the MySQLCredentials.inc file. They’re posted with a localhost machine name, student username, student password, and sampledb database.
  1. Not to be funny, but the second thing to check are credentials. Specifically, you need to check the credentials in the ConvertBlobToImage.php file. They’re individually entered in the connect string of this file because otherwise they put something in front of the header, which is disallowed to render the image.
  1. Check to see if the text or image file made it to the /var/www/html/lob/temp directory. If they made it that far but no further, check to see if you have valid procedures in the student schema.
  1. Check whether the TEXT and MEDIUMBLOB are loaded into the database. You use the LENGTH function, like this:
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;
  1. Check if the item_id value is found in the list of values.
  1. If you’re stumped, add a comment and explain what’s up.

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

Written by maclochlainn

December 28th, 2022 at 10:59 pm

Posted in Database,LAMP,Linux,MySQL,MySQL 8,PHP,Unix

Tagged with , ,

AlmaLinux Install & Configuration

without comments

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.

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.

Written by maclochlainn

December 21st, 2022 at 5:29 pm

Posted in AlmaLinux,Apache,Database,DBA,Java,Java 17,LAMP,Linux,MySQL,MySQL 8,MySQL Connect/J,Oracle,Oracle 11g,Oracle DBA,Oracle Developer,Oracle XE,pdo,Perl,Perl DBI,pgAdmin4,PHP,Postgres,PostgreSQL,PostgreSQL 15,Python 3.x,Rust,VMWare,VSCode

Tagged with , , , , , , , ,

AlmaLinux+Java+MySQL

with 2 comments

AlmaLinux generally has Java installed. You can check whether java is installed with this command:

which -a java

It should return:

/usr/bin/java

Then, you can check the Java version with this command:

java -version

For AlmaLinux 9, it should return:

openjdk version "11.0.17" 2022-10-18 LTS
OpenJDK Runtime Environment (Red_Hat-11.0.17.0.8-2.el9_0) (build 11.0.17+8-LTS)
OpenJDK 64-Bit Server VM (Red_Hat-11.0.17.0.8-2.el9_0) (build 11.0.17+8-LTS, mixed mode, sharing)

Next, you check whether javac is installed. You can use the which command to determine whether it is installed. Generally, its not installed and you use this command to

sudo dnf search jdk | egrep -- '-17'

It should return:

Last metadata expiration check: 0:11:17 ago on Mon 19 Dec 2022 11:32:48 PM EST.
java-17-openjdk.x86_64 : OpenJDK 17 Runtime Environment
java-17-openjdk-demo.x86_64 : OpenJDK 17 Demos
java-17-openjdk-devel.x86_64 : OpenJDK 17 Development Environment
java-17-openjdk-headless.x86_64 : OpenJDK 17 Headless Runtime Environment
java-17-openjdk-javadoc.x86_64 : OpenJDK 17 API documentation
java-17-openjdk-javadoc-zip.x86_64 : OpenJDK 17 API documentation compressed in a single archive
java-17-openjdk-jmods.x86_64 : JMods for OpenJDK 17
java-17-openjdk-src.x86_64 : OpenJDK 17 Source Bundle
java-17-openjdk-static-libs.x86_64 : OpenJDK 17 libraries for static linking

Now, you can install the Java JDK with the following dnf command:

sudo dnf install java-17-openjdk java-17-openjdk-devel

The log file for this is:

Display detailed console log →

Last metadata expiration check: 0:28:26 ago on Mon 19 Dec 2022 11:32:48 PM EST.
Dependencies resolved.
================================================================================
 Package                    Arch     Version                  Repository   Size
================================================================================
Installing:
 java-17-openjdk            x86_64   1:17.0.5.0.8-2.el9_0     appstream   237 k
 java-17-openjdk-devel      x86_64   1:17.0.5.0.8-2.el9_0     appstream   4.7 M
Installing dependencies:
 java-17-openjdk-headless   x86_64   1:17.0.5.0.8-2.el9_0     appstream    40 M
 ttmkfdir                   x86_64   3.0.9-65.el9             appstream    52 k
 xorg-x11-fonts-Type1       noarch   7.5-33.el9               appstream   499 k
 
Transaction Summary
================================================================================
Install  5 Packages
 
Total download size: 45 M
Installed size: 199 M
Is this ok [y/N]: y
Downloading Packages:
(1/5): java-17-openjdk-17.0.5.0.8-2.el9_0.x86_6 342 kB/s | 237 kB     00:00    
(2/5): ttmkfdir-3.0.9-65.el9.x86_64.rpm         520 kB/s |  52 kB     00:00    
(3/5): xorg-x11-fonts-Type1-7.5-33.el9.noarch.r 849 kB/s | 499 kB     00:00    
(4/5): java-17-openjdk-devel-17.0.5.0.8-2.el9_0 1.7 MB/s | 4.7 MB     00:02    
(5/5): java-17-openjdk-headless-17.0.5.0.8-2.el 6.1 MB/s |  40 MB     00:06    
--------------------------------------------------------------------------------
Total                                           6.3 MB/s |  45 MB     00:07     
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Regex version mismatch, expected: 10.40 2022-04-14 actual: 10.37 2021-05-26
Regex version mismatch, expected: 10.40 2022-04-14 actual: 10.37 2021-05-26
  Running scriptlet: java-17-openjdk-headless-1:17.0.5.0.8-2.el9_0.x86_64   1/1 
  Preparing        :                                                        1/1 
  Installing       : java-17-openjdk-headless-1:17.0.5.0.8-2.el9_0.x86_64   1/5 
  Running scriptlet: java-17-openjdk-headless-1:17.0.5.0.8-2.el9_0.x86_64   1/5 
  Installing       : ttmkfdir-3.0.9-65.el9.x86_64                           2/5 
  Installing       : xorg-x11-fonts-Type1-7.5-33.el9.noarch                 3/5 
  Running scriptlet: xorg-x11-fonts-Type1-7.5-33.el9.noarch                 3/5 
  Installing       : java-17-openjdk-1:17.0.5.0.8-2.el9_0.x86_64            4/5 
  Running scriptlet: java-17-openjdk-1:17.0.5.0.8-2.el9_0.x86_64            4/5 
  Installing       : java-17-openjdk-devel-1:17.0.5.0.8-2.el9_0.x86_64      5/5 
  Running scriptlet: java-17-openjdk-devel-1:17.0.5.0.8-2.el9_0.x86_64      5/5 
  Running scriptlet: java-17-openjdk-headless-1:17.0.5.0.8-2.el9_0.x86_64   5/5 
  Running scriptlet: java-17-openjdk-1:17.0.5.0.8-2.el9_0.x86_64            5/5 
  Running scriptlet: java-17-openjdk-devel-1:17.0.5.0.8-2.el9_0.x86_64      5/5 
  Verifying        : java-17-openjdk-1:17.0.5.0.8-2.el9_0.x86_64            1/5 
  Verifying        : java-17-openjdk-devel-1:17.0.5.0.8-2.el9_0.x86_64      2/5 
  Verifying        : java-17-openjdk-headless-1:17.0.5.0.8-2.el9_0.x86_64   3/5 
  Verifying        : ttmkfdir-3.0.9-65.el9.x86_64                           4/5 
  Verifying        : xorg-x11-fonts-Type1-7.5-33.el9.noarch                 5/5 
 
Installed:
  java-17-openjdk-1:17.0.5.0.8-2.el9_0.x86_64                                   
  java-17-openjdk-devel-1:17.0.5.0.8-2.el9_0.x86_64                             
  java-17-openjdk-headless-1:17.0.5.0.8-2.el9_0.x86_64                          
  ttmkfdir-3.0.9-65.el9.x86_64                                                  
  xorg-x11-fonts-Type1-7.5-33.el9.noarch                                        
 
Complete!

After installing javac, you can verify it with the which command, and check the version with the javac utility.

which -a javac

It should return:

/usr/bin/javac

Then, you can check the Java version with this command:

java -version

For AlmaLinux 9, it should return:

javac 17.0.5

Now, you need to download and install the jdk with the dnf utility. You download the jdk package with the wget utility.

wget https://download.oracle.com/java/17/latest/jdk-17_linux-x64_bin.rpm

It will generate the following console output:

--2022-12-20 00:12:34--  https://download.oracle.com/java/17/latest/jdk-17_linux-x64_bin.rpm
Resolving download.oracle.com (download.oracle.com)... 23.192.208.88
Connecting to download.oracle.com (download.oracle.com)|23.192.208.88|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 163101336 (156M) [application/x-redhat-package-manager]
Saving to: ‘jdk-17_linux-x64_bin.rpm’
 
jdk-17_linux-x64_bi 100%[===================>] 155.54M  11.1MB/s    in 17s     
 
2022-12-20 00:12:51 (9.01 MB/s) - ‘jdk-17_linux-x64_bin.rpm’ saved [163101336/163101336]

You install the jdk package with the dnf utility.

sudo rpm -Uvh jdk-17_linux-x64_bin.rpm

The log file for this is:

Display detailed console log →

warning: jdk-17_linux-x64_bin.rpm: Header V3 RSA/SHA256 Signature, key ID ec551f03: NOKEY
Verifying...                          ################################# [100%]
Regex version mismatch, expected: 10.40 2022-04-14 actual: 10.37 2021-05-26
Regex version mismatch, expected: 10.40 2022-04-14 actual: 10.37 2021-05-26
Preparing...                          ################################# [100%]
Updating / installing...
   1:jdk-17-2000:17.0.5-ga            ################################# [100%]

After installing everything, you need to set the default Java. You can discover the available Java versions with the following command:

sudo alternatives --config java

It should return a list and the ability to select one by using the “Selection” number. I recommend you chose #2.

There are 3 programs which provide 'java'.
 
  Selection    Command
-----------------------------------------------
   1           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.17.0.8-2.el9_0.x86_64/bin/java)
   2           java-17-openjdk.x86_64 (/usr/lib/jvm/java-17-openjdk-17.0.5.0.8-2.el9_0.x86_64/bin/java)
*+ 3           /usr/java/jdk-17.0.5/bin/java
 
Enter to keep the current selection[+], or type selection number: 2

Then, you can check the Java version with this command:

java -version

Now, it should return:

openjdk version "17.0.5" 2022-10-18 LTS
OpenJDK Runtime Environment (Red_Hat-17.0.5.0.8-2.el9_0) (build 17.0.5+8-LTS)
OpenJDK 64-Bit Server VM (Red_Hat-17.0.5.0.8-2.el9_0) (build 17.0.5+8-LTS, mixed mode, sharing)

You should define the $JAVA_HOME environment variable in the /etc/profile file. Sometimes, it is also appropriate to include it in your .bashrc file.

export set JAVA_HOME="/usr/lib/jvm/java-17-openjdk-17.0.5.0.8-2.el9_0.x86_64/bin"

You should also add it to your $PATH variable in your .bashrc file, like:

export set PATH=$PATH:$JAVA_HOME

Now, let’s write the basic “Hello World” program in Java:

// Define the Java program.
public class HelloWorld {
  public static void main(String[] args) {
    System.out.println("Hello World!");
  }
}

Compile it with:

javac HelloWorld.java

Run it with the java command:

java HelloWorld

It prints:

Hello World!

Let’s download the MySQL/J Connector from the MySQL website, where we con select the operating system and its version, as shown in the image.

After you download the mysql-connector-j RPM package, you can install it with the following dnf command:

sudo dnf install -y mysql-connector-j-8.0.31-1.el9.noarch.rpm

The log file for this is:

Display detailed console log →

Last metadata expiration check: 2:02:56 ago on Mon 19 Dec 2022 11:32:48 PM EST.
Dependencies resolved.
================================================================================
 Package                Arch        Version             Repository         Size
================================================================================
Installing:
 mysql-connector-j      noarch      1:8.0.31-1.el9      @commandline      2.3 M
 
Transaction Summary
================================================================================
Install  1 Package
 
Total size: 2.3 M
Installed size: 2.7 M
Downloading Packages:
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Regex version mismatch, expected: 10.40 2022-04-14 actual: 10.37 2021-05-26
Regex version mismatch, expected: 10.40 2022-04-14 actual: 10.37 2021-05-26
  Preparing        :                                                        1/1 
  Installing       : mysql-connector-j-1:8.0.31-1.el9.noarch                1/1 
  Verifying        : mysql-connector-j-1:8.0.31-1.el9.noarch                1/1 
 
Installed:
  mysql-connector-j-1:8.0.31-1.el9.noarch                                       
 
Complete!

You should add the $CLASSPATH to your .bashrc file. Add the following line to your .bashrc file and resource your .bashrc file to test the JDBC driver.

export set CLASSPATH="/usr/share/java/mysql-connector-j.jar:."

Let’s write a slightly larger Java program that tests connectivity to the MySQL database, like:

// Import classes.
import java.sql.*;
 
/* You can't include the following on Linux without raising an exception. */
// import com.mysql.jdbc.Driver;
 
public class MySQLConnector {
  public MySQLConnector() {
    /* Declare variables that require explicit assignments because
       they're addressed in the finally block. */
    Connection conn = null;
    Statement stmt = null;
    ResultSet rset = null;
 
    /* Declare other variables. */
    String url;
    String username = "student";
    String password = "student";
    String database = "studentdb";
    String hostname = "localhost";
    String port = "3306";
    String sql;
 
    /* Attempt a connection. */
    try {
      // Set URL.
      url = "jdbc:mysql://" + hostname + ":" + port + "/" + database;
 
      // Create instance of MySQLDriver.
      Class.forName ("com.mysql.cj.jdbc.Driver").newInstance();
      conn = DriverManager.getConnection (url, username, password);
 
      // Query the version of the database.
      sql = "SELECT version()";
      stmt = conn.createStatement();
      rset = stmt.executeQuery(sql);
 
      System.out.println ("Database connection established");
 
      // Read row returns for one column.
      while (rset.next()) {
        System.out.println("MySQLDriver Version [" + rset.getString(1) + "]"); }
 
    }
    catch (SQLException e) {
      System.err.println ("Cannot connect to database server:");
      System.out.println(e.getMessage());
    }
    catch (ClassNotFoundException e) {
      System.err.println ("Cannot find MySQL driver class:");
      System.out.println(e.getMessage());
    }
    catch (InstantiationException e) {
      System.err.println ("Cannot instantiate class:");
      System.out.println(e.getMessage());
    }
    catch (IllegalAccessException e) {
      System.err.println ("Illegal access exception:");
      System.out.println(e.getMessage());
    }
    finally {
      if (conn != null) {
        try {
          rset.close();
          stmt.close();
          conn.close();
          System.out.println ("Database connection terminated");
        }
        catch (Exception e) { /* ignore close errors */ }
      }
    }
  }
  /* Unit test. */
  public static void main(String args[]) {
    new MySQLDriver();
  }
}

Just a note, there’s a deprecated behavior introduced in MySQL 8.0.24, which produces the following error message when compiled looking for deprecation:

javac -Xlint:deprecation  MySQLDriver.java

It produces the following error message, which I hope to sort and update later in the week:

MySQLDriver.java:30: warning: [deprecation] newInstance() in Class has been deprecated
      Class.forName ("com.mysql.cj.jdbc.Driver").newInstance();
                                                ^
  where T is a type-variable:
    T extends Object declared in class Class
1 warning

The code does compile because the deprecation is only a warning. When you run the program, like:

java MySQLDriver

It returns, confirming a connection to the MySQL database:

Database connection established
MySQLDriver Version [8.0.30]
Database connection terminated

As always, I hope this helps those trying to sort out new behaviors.

Written by maclochlainn

December 19th, 2022 at 9:51 pm

Posted in Java,Java 17,MySQL,MySQL 8,MySQL Connect/J

Tagged with , ,

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