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Day: March 8, 2024

Subsetting Data Frames in R using Multiple Conditions

Steven Sanderson can’t stop at one filter:

In data analysis with R, subsetting data frames based on multiple conditions is a common task. It allows us to extract specific subsets of data that meet certain criteria. In this blog post, we will explore how to subset a data frame using three different methods: base R’s subset() function, dplyr’s filter() function, and the data.table package.

Click through for examples.

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A Primer on Vector Similarity Search

Pavan Belagatti talks vectors:

In the realm of generative AI, vectors play a crucial role as a means of representing and manipulating complex data. Within this context, vectors are often high-dimensional arrays of numbers that encode significant amounts of information. For instance, in the case of image generation, each image can be converted into a vector representing its pixel values or more abstract features extracted through deep learning models.

These vectors become the language through which AI algorithms understand and generate new content. By navigating and modifying these vectors in a multidimensional space, generative AI produces new, synthetic instances of data — whether images, sounds or text — that mimic the characteristics of the original dataset. This vector manipulation is at the heart of AI’s ability to learn from data and generate realistic outputs based on that learning.

Read on for a high-level overview of the topic.

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Reading Azure SQL Audit Logs from Azure Storage

Matt Changchien covers a strange scenario:

When you read an Azure SQL Database audit log from Azure Storage using sys.fn_get_audit_file, you might encounter a situation where the audit log appears non-empty, but the query still returns an empty result. This discrepancy can be puzzling, especially when the official documentation doesn’t explicitly mention any limitations or requirements for the sys.fn_get_audit_file system function.

In this post, I will shed light on these limitations and demonstrate them to provide clarity.

Read on to see when this might happen and what you can do about it.

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Avoid the securityadmin Role

Etienne Lopes recommends against a particular SQL Server role:

I usually avoid using the two “radical” words: “never” and “always” but regarding the membership need for the “securityadmin” server role since SQL 2005/2008 onward, I find it hard to come up with a good reason why it should ever be used, especially considering the security risks involved. A few weeks ago, while checking permissions for some logins in a (critical) SQL Server 2019 instance, I came across some really worrying situations, among which I found this one… again! Although it wasn’t the worst I found there (the worst was to bad to even mention here) I felt impelled to write about this one, maybe because the risks may not be so obvious or are somewhat concealed… Well, let’s bring them to light! 

Cosnidering that securityadmin can increase its own rights to sysadmin, you’d might as well just grant that login sysadmin.

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Chad Callihan makes a comparison:

I haven’t had a MySQL post for awhile, so it’s time to add some variety to the blog.

There are a couple of different ways to export data with a SELECT query in MySQL: INTO OUTFILE and INTO DUMPFILE. Let’s use the MySQL Sakila sample database and walk through some examples to compare these two options.

Read on to see when you might want to use each of these.

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Restoring a Tablespace using Barman on Windows

Semab Tariq restores a database:

I recently had the opportunity to contribute to a customer project, where the objective was to establish a system for PostgreSQL full backups and seamless restoration. Considering Barman’s successful functionality on Linux, we decided to explore its compatibility with Windows. Secondly, no other tool claims to work on Windows to take backups and perform a restore

From official documentation it is mentioned that: 
Backup of a PostgreSQL server on Windows is possible, but it is still experimental because it is not yet part of our continuous integration system.

Click through for the walkthrough.

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