Introduction In this article, we are going to see how Index Selectivity works in relational database systems and why the database Optimizer might choose to avoid using an index if the number of matching records is large. Index selectivity is inversely proportional to the number of index entries matched by a given value. So, a unique index has the highest selectivity because only a single entry can be matched by any given value. On the other hand, if column values are skewed, then a column value matching a large number of table... Read More

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We already have a tutorial on how to connect to the MySQL database using Node.js. Well, you can read it if you want to know, but it only allows you to interact with the database, what if you want to insert some new records directly from Node.js? You can also easily do this by executing […]

A few days ago, Oracle released three new MySQL GA versions: 8.2.0, 8.0.35 and 5.7.44.  I skimmed the release notes (8.2.0, 8.0.35 and 5.7.44), and I am not impressed.  I guess that I would be even less impressed / more disappointed if I had checked in greater detail, and if I had reviewed the 8.1.0, 8.0.34 and 5.7.43 release notes.  The subject of my disappointment is Oracle not

PHP developer and Laravel content creator Marian Pop shares a fantastic developer interview with the OpenLampTech newsletter readers.

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Organizations often shard their database to scale beyond what simply adding resources to a single server can provide. When you horizontally shard your database, you essentially break the data up and split it across multiple database servers. Hearing this, you might think that adding more servers means adding more maintenance overhead to your staff, and more expenses on your budget, with the tradeoff that your organization can handle more database traffic. While there is definitely some truth to that in certain situations, there’s oftentimes more to the story that's not as obvious. In this article, we’ll cover three ways that sharding your database can benefit your organization beyond additional throughput. Minimized impact on failures There’s an old saying in architecting infrastructure: two is one, and one is none. The implication is that you should never have one of anything, as it creates a single point of failure. This is true for your …

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We will walk you through the process of connecting to SQL Server using Devart SDAC, including installation and examples of how to interact with the components.

The post How to Connect to SQL Server in Delphi with Devart SDAC appeared first on Devart Blog.

In MySQL, you might wonder what’s the difference between UPSERT and INSERT commands. The INSERT clause adds new rows into a table. It only puts new data and does not change any old data. On the other hand, the UPSERT does two jobs. It adds new rows, but if a row with the same key […]

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This blog tells how to use the OCI APM (Application Performance Monitor) for MySQL

MySQL offers a wide array of options to configure replication, but with all of those options, how can you be sure you are doing it right? Replication is the first step to providing a higher level of availablity to your MySQL database. A well configured replication architecture can be the difference between your data being highly available, or your MySQL setup becoming a management nightmare. At PlanetScale, we support hundreds of thousands of database clusters, all using replication to provide high availability, so we have a little bit of experience in this arena! In this article, we’re going to explore some of the best practices when it comes to replication, both locally and across longer distances. Use an active/passive configuration When replicating with active/passive mode, one MySQL server acts as the source and all other servers are read-only replicas from that source. In this configuration, the replicas can be used to serve up read-only …