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Displaying posts with tag: Windows OS (reset)
Node.js MySQL Error

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

The error is caused by this import statement:

const mysql = require('mysql') 

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

    throw err;

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

We had an interesting set of questions regarding the REGEXP comparison operator in MySQL today in both sections of Database Design and Development. They wanted to know the default behavior.

For example, we built a little movie table so that we didn’t change their default sakila example database. The movie table was like this:

( movie_id     int unsigned primary key auto_increment
, movie_title  varchar(60)) auto_increment=1001;

Then, I inserted the following rows:

( movie_title )
 ('The King and I')
,('The I Inside')
,('I am Legend');

Querying all results with this query:

SELECT * FROM movie;

It returns the following results:

| movie_id | movie_title    |
|     1001 | The King and I |
|     1002 | I              |
|     1003 | The I Inside   |
|     1004 | I am Legend …
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MySQL CSV Output

Saturday, I posted how to use Microsoft ODBC DSN to connect to MySQL. Somebody didn’t like the fact that the PowerShell program failed to write a *.csv file to disk because the program used the Write-Host command to write to the content of the query to the console.

I thought that approach was a better as an example. However, it appears that it wasn’t because not everybody knows simple redirection. The original program can transfer the console output to a file, like:

powershell .\MySQLODBC.ps1 > output.csv

So, the first thing you need to do is add a parameter list, like:

param (

Anyway, it’s trivial to demonstrate how to modify the PowerShell program to write to a disk. You should also create a virtual PowerShell drive before writing the file. That’s because you can change the physical directory anytime you want with minimal changes to rest of …

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This post explains and demonstrates how to install, configure, and use the MySQL’s ODBC libraries and a DSN (Data Source Name) to connect your Microsoft PowerShell programs to a locally or remotely installed MySQL database. After you’ve installed the MySQL ODBC library, use Windows search field to find the ODBC Data Sources dialog and run it as administrator.

There are four steps to setup, test, and save your ODBC Data Source Name (DSN) for MySQL. You can click on the images on the right to launch them in a more readable format or simply read the instructions.

MySQL ODBC Setup Steps

  1. Click the SystemDSN tab to see he view which is …
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MySQL 5-Table Procedure

A student wanted a better example of writing a MySQL Persistent Stored Module (PSM) that maintains transactional scope across a couple tables. Here’s the one I wrote about ten years ago to build the MySQL Video Store model. It looks I neglected to put it out there before, so here it is for reference.

-- Conditionally drop procedure if it exists.

-- Reset the delimiter so that a semicolon can be used as a statement and block terminator.

SELECT 'CREATE PROCEDURE contact_insert' AS "Statement";
CREATE PROCEDURE contact_insert
( pv_member_type         CHAR(12)
, pv_account_number      CHAR(19)
, pv_credit_card_number  CHAR(19)
, pv_credit_card_type    CHAR(12)
, pv_first_name          CHAR(20)
, pv_middle_name         CHAR(20)
, pv_last_name           CHAR(20)
, pv_contact_type        CHAR(12)
, pv_address_type        CHAR(12)
, pv_city                CHAR(30)
, pv_state_province      CHAR(30)
, …
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Setting SQL_MODE

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

Create the set_full_group_by procedure:

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

-- Reset delimter to allow semicolons to terminate statements.

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

  /* Check whether full group by is set in the connection and
     if unset, set it in the scope of the connection. */
  END IF; …
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The first tutorial supplementing the MySQL Connector/NET Developer Guide showed you how to connect and run static INSERT statement. It was a barebones PowerShell script with the MySQL Connector. This post shows you how to run a PowerShell script that uses a dynamic form to gather the MySQL credentials and then run a static query. Below is the MySQL Credentials form.

You enter the correct user name, password, hostname (or IP address), port, and database, like this:

Here’s the complete code for this staticQuery.ps1 PowerShell script:

# Add libraries for form components. …
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MySQL sakila Database

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

Samples and Examples 8.0.22

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

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

  1. Go to and download the files for the …
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MySQL Shell Parsing

I’ve been experimenting with the mysqlsh since installing it last week. It’s been interesting. Overall, I’m totally impressed but I did find a problem with how it parses stored procedures.

First thought is always, is it my code? I checked the file by running it as a script file through MySQL Workbench. It ran perfectly in MySQL Workbench but failed repeatedly when run from the mysqlsh utility. Next step, reduce the code to a small test case, retest it, and log a bug if it is replicated. My test case in a test.sql file generates the following errors when run from the mysqlsh utility:

 MySQL  localhost:33060+ ssl  studentdb  SQL > source test.sql
Query OK, 0 rows affected (0.0003 sec)
ERROR: 1064: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the …
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MySQL Unicode Warning

It’s always interesting when I upgrade from one release to the next. I learn new things, and in the case of MySQL’s installation and maintenance I become more grateful for the great team of developers working to produce MySQL 8.

A warning that caught my eye in MySQL 8 (8.0.21) was this one on Unicode with the utf8 character code:

Warning (code 3719): 'utf8' is currently an alias for the character set UTF8MB3, but will be an alias for UTF8MB4 in a future release. Please consider using UTF8MB4 in order to be unambiguous.

Currently, a character alias for utf8mb3 is an alias for the deprecated utf8mb3 (a 3-byte character set) until it is removed. When the utf8mb3 character set is …

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