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Displaying posts with tag: sql (reset)
MySQL and PHP Basics Part I

I have had some requests to write some blogs on the basics of using PHP and MySQL together.  This will not be a series for the experienced as it will start at a level where I will go into a lot of details but expect very few prerequisites from the reader.  If this is not you, please move on. If it is you and you read something you do not understand, please contact me to show me where I assumed too much.

PHP and MySQL are both in their mid twenties and both vital in the worlds of developers.  With the big improvements in PHP 7 and MySQL 8, I have found a lot of developers flocking to both but stymied by the examples they see as their are many details not explained. So let's get to the explaining!
1. Use the latest software
If you are not using PHP 7.2 or 7.3 (or maybe 7.1) then you are missing out in features and performance.  The PHP 5.x series is deprecated, no longer support, and …

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2019 Database Trends – SQL vs. NoSQL, Top Databases, Single vs. Multiple Database Use

Wondering which databases are trending in 2019? We asked hundreds of developers, engineers, software architects, dev teams, and IT leaders at DeveloperWeek to discover the current NoSQL vs. SQL usage, most popular databases, important metrics to track, and their most time-consuming database management tasks. Get the latest insights on MySQL, MongoDB, PostgreSQL, Redis, and many others to see which database management systems are most favored this year.

SQL vs. NoSQL

As any database administrator knows, the first question you have to ask yourself is whether to use a SQL or NoSQL database for your application. …

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Your SQL IS NOT JavaScript (neither PHP)

IS NULL, IS NOT NULL, truthiness among other assertions on MySQL and PostgreSQL

People like to complain about JavaScript, how can one thing be equal to the other, i.e. null == undefined evaluates to true unless you use the triple equals ===. Other dynamic typed languages have its peculiarities, such as Ruby where 0 == true evaluates to true, the reason for Ruby is that considers 0 as a value and any value evaluates to true.

How about SQL? The answer is… it depends.

Which database are you using?

Some may be more forgiving, like MySQL doing casts for you all over the place, or more strict like PostgreSQL where you can only compare the truthiness of something of the same type.

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Installing WordPress 5 on ZEIT Now with MySQL Hosting

Want to deploy WordPress 5.0 on the Now platform by ZEIT? Our friends over at ZEIT’s Now global serverless deployment platform whipped up a great tutorial for WordPress5-on-Now using cheap MySQL hosting instances from ScaleGrid. With such strong interest in this installation, we decided to write up the steps to configure your MySQL database on the ScaleGrid side to get you up and running ever faster with WordPress on Now.

Leave your comments: https://t.co/exuBzSHkHM
@now/wordpress summary:
◆ λ size = 13mb
◆ Just needs `wp-config.php`
◆ All static assets output directly to CDN …

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MySQL Tutorial – Understanding The Seconds Behind Master Value

In a MySQL hosting replication setup, the parameter Seconds_Behind_Master (SBM), as displayed by the SHOW SLAVE STATUS command, is commonly used as an indication of the current replication lag of the slave. In this blog post, we examine how to understand and interpret this value in various situations.

Possible Values of  Seconds Behind Master

The value of SBM, as explained in the  MySQL documentation, depends on the state of the MySQL slave in general, and the states of MySQL slave SQL_THREAD and IO_THREAD in particular. While IO_THREAD connects with the master and reads the updates, SQL_THREAD applies these updates on the slave. Let’s examine the possible values of SBM during different states of the MySQL Slave.

When SBM Value is Null

  • SBM is …
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Why, When and How to Use DTO Projections with JPA and Hibernate

The post Why, When and How to Use DTO Projections with JPA and Hibernate appeared first on Thoughts on Java.

DTOs are easy to use and the most efficient projection for read-only operations. So, whenever you don’t need to change the requested information, you should prefer a DTO projection.

But what exactly is a DTO? How does such a projection work with Hibernate? And how can you use it in your queries?

I will answer all of these questions in this article. And I will even show you a way to use a DTO projection that doesn’t require a custom DTO class.

DTO Projections with …

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What the Heck is a Lateral Derived Table?

MySQL 8.0.14 came with Lateral Derived Tables as a new feature.  But what is that and how do you use them?

Let's start what a derived table is.  According to the manual (link below) A derived table is an expression that generates a table within the scope of a query FROM clause.   You are probably used to using a subquery or JSON_TABLE where that query feeds data into another query.

Derived Tables

Derived tables can return a scalar, column, row, or table. But there are limits to their use.
A derived table cannot be a correlated subquery and a derived table cannot contain references to other tables of the same SELECT. And previous to MySQL 8.0.14, a derived table cannot contain outer references.

Okay, so what is an 'outer reference'? The SQL-92 standard …

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MySQL High Availability Framework Explained – Part II

In Part I, we introduced a High Availability (HA) framework for MySQL hosting and discussed various components and their functionality. Now in Part II, we will discuss the details of MySQL semisynchronous replication and the related configuration settings that help us ensure redundancy and consistency of the data in our HA setup. Make sure to check back in for Part III where we will review various failure scenarios that could arise and the way the framework responds and recovers from these conditions.

What is MySQL Semisynchronous Replication?

Simply put, in a MySQL semisynchronous replication configuration, the master …

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My 2019 Database Wishlist

Last year I published my 2018 Database Wishlist, which I recently revisited to check what happened and what didn’t. Time for a 2019 wishlist.

I am not going to list items from my 2018 list, even if they didn’t happen or they partially happened. Not because I changed my mind about their importance. Just because I wrote about them recently, and I don’t want to be more boring than I usually am.

External languages for MySQL and MariaDB

MariaDB 10.3 implemented a parser for PL/SQL stored procedures. This could be good for their business, as it facilitates the migration from Oracle. But …

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Revisiting my 2018 Database Wishlist

It is December and 2018 is going to end. In January, when it just started, I wrote my 2018 Database Wishlist. Probably next January I’ll write another list. But first, it makes sense to review the last one. If some of my wishes actually happen, I really should know that – I don’t want to miss something nice, or forget topics that I considered interesting less than one year ago. Well, let’ s do some copy/paste and some googling…

More research on Learned Indexes

I’m not sure if more research actually happened – I hope so, and I hope that we’ll see its results at some point. At least, it seems that the topic was not forgotten. It was mentioned at least at Artificial Intelligence …

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