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Posts in the “mysql” category

MySQL create database example - How to create a MySQL database and user account for Drupal

MySQL “create database” FAQ: Can you share an example of how to create a MySQL database, including (a) creating the MySQL database and (b) a new MySQL database user, with all appropriate MySQL grant permissions for that user?

Sure. I've written about the process of How to add/create a MySQL user before, but I just ran across the Drupal installation documentation, which also has a nice description for how to create a MySQL database (for use with Drupal), so I thought I'd include some of their documentation here, along with some notes from my own recent Drupal and MySQL installation.

1) Create a new MySQL database

The first part of the Drupal installation document refers to creating a MySQL database:

How to search for a string in all fields of every table in a MySQL database

Here’s a cool tip: if you want to search for a text string in all fields of all tables of a MySQL database, you can use phpMyAdmin to do this very easily. Here are the steps to search every MySQL/MariaDB database table.

1) Select the desired database

The first step is to select the database you want to search. Don’t select a table — just select the database you want to search. (If you select a table you’ll get a different search form in Step 2.)

A MySQL database backup (mysqldump) shell script

MySQL database backup FAQ: Can you share a Linux shell script that I can use to make a MySQL backup (i.e., a shell script that wraps the mysqldump command)?

I currently have a collection of websites on several different servers (including GoDaddy and A2 Hosting web servers), so I was just spending some time trying to automate my MySQL database backups. To that end, I just created a MySQL shell script that I use on each Linux server to make my database backups, and I thought I'd share that script here.

MySQL show status: How to show open database connections

MySQL "show status" FAQ: Can you demonstrate how to use the MySQL show status command to show MySQL variables and status information, such as the number of open MySQL connections?

I don't have a whole lot of time today to give this a detailed discussion, but here is a quick look at some MySQL work that I did recently to show MySQL open database connections.

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A MySQL add user and grant example

MySQL “users” FAQ: How do I add a new user to a MySQL database (i.e., how do I create a MySQL user account, and then grant database permissions to that new user account)?

Solution: MySQL add user and grant syntax

Here’s an example of what I did recently to (a) create a new MySQL database and then (b) add a new MySQL user account to work with that database.

Step 1: Log in to the database

First, from my Unix prompt, I logged into my MySQL database server with the mysql command line client:

MySQL FAQ: How do I show the fields or schema of a database table?

MySQL FAQ: How do I show the schema of a MySQL database table?

Answer: Use the desc command from the MySQL command line client.

For instance, in my current application I have a database table named orders, and when I need to see the schema for that table I show it with the desc command like this:

desc orders

The MySQL output looks like this:

How to perform a SQL query for fields that are null (or not null)

For some reason I can never remember how to search for database table fields that are either NULL or NOT NULL. I always try to use the = operator or something else.

So, for myself, here’s an example of how to perform a SQL query and find all records where a field in a database table is NULL:

SELECT * FROM foo WHERE bar IS NULL;

And here’s how to perform a SQL query showing all records in a database table where a column is NOT NULL:

A MySQL Vacuum database tables script (auto_increment reset)

MySQL vacuum FAQ: How do I vacuum a MySQL database table, or an entire MySQL database?

This may be an unusual situation, but as I'm creating a new application that uses a MySQL database, I've found that I want a "MySQL vacuum" operation; I want to reset all my MySQL auto_increment counters back to 1 without having to completely drop and then re-create my MySQL database.

Specifically what I'm doing is this:

A MySQL foreign keys “drop table” and re-create table example

MySQL FAQ: How can I drop a series of database tables that have foreign key relationships between them?

If you ever have a problem where you need to drop a series of MySQL database tables that have foreign key relationships between them, the key to doing this is setting the FOREIGN_KEY_CHECKS variable before and after your MySQL DROP TABLE queries.

For example, something like this should work:

MySQL drop table and foreign keys tip - the FOREIGN_KEY_CHECKS variable

MySQL “DROP TABLE” FAQ: Help, my MySQL database tables have a lot of foreign keys, and as a result it's a pain to use the MySQL DROP TABLE command in my scripts; they keep failing because of all the foreign keys. Is there something I can do to work around this DROP TABLE foreign keys problem?

A MySQL “create table” syntax example

I used to use MySQL every day for years, but over the last two years I haven't used it much. Today I needed to create a MySQL database table, and had to wonder for a few moments what the MySQL CREATE TABLE syntax was. Fortunately I have plenty of examples out here.

Here's a quick example of a MySQL "users" table:

Example MySQL database design: A Nagios MySQL database design

MySQL database FAQ: Can you provide a large, complete, example MySQL database design?

I recently worked on a project where I wrote a web-based user interface that would let "everyday users" maintain their own Nagios configuration data. After logging in to the web interface, users could modify the Nagios configuration as desired, for instance, when they added new equipment to their network.

A MySQL database table index example

MySQL FAQ: How do I create a MySQL database table index?

Here's an example of how to create an index on a MySQL database table. In this particular example my table uses the MySQL InnoDB database engine, but that doesn't matter too much -- it just happens to be a MySQL database engine that supports foreign key relationships.

To get started, here's the SQL definition of a MySQL table I've named ftp_files:

MySQL Error 1293 - Incorrect table definition (TIMESTAMP)

MySQL Error 1293 FAQ: Help, I'm getting a MySQL incorrect table definition error message related to a TIMESTAMP column. How do I get past it?

If you ever get this MySQL Error 1293 (like I just did):

ERROR 1293 (HY000): Incorrect table definition; there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT or ON UPDATE clause

fear not, it may not be too bad. Let's take a look.

The MySQL default port is ...

Today I was configuring a MySQL JNDI connection pool on a Glassfish server, when my brain went completely blank, and I couldn't remember what port MySQL listens on by default.

After a few moments of research, including looking at some output from netstat, I found the answer ... the MySQL default port is 3306.

3306

 

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