Home » Tag Archives: Databases (page 5)

Tag Archives: Databases

Yet Another 10 Common Mistakes Java Developers Make When Writing SQL (You Won’t BELIEVE the Last One)

software-development-2-logo

(Sorry for that click-bait heading. Couldn’t resist!) We’re on a mission. To teach you SQL. But mostly, we want to teach you how to appreciate SQL. You’ll love it! Getting SQL right or wrong shouldn’t be about that You’re-Doing-It-Wrong™ attitude that can be encountered often when evangelists promote their object of evangelism. Getting SQL right should be about the fun ...

Read More »

MySQL Transaction Isolation Levels and Locks

mysql-logo

Recently, an application that my team was working on encountered problems with a MySQL deadlock situation and it took us some time to figure out the reasons behind it. This application that we deployed was running on a 2-node cluster and they both are connected to an AWS MySQL database. The MySQL db tables are mostly based on InnoDB which ...

Read More »

Seven Databases in Seven Weeks – Hbase Day 2

apache-hbase-logo

This post is a recap of the second day of Hbase from the Seven Databases in Seven Weeks book. Most of the commands and scripts can be found at GitHub: https://github.com/eyalgo/seven-dbs-in-seven-weeks/tree/master/hbase/day_2 Streaming Script The first thing in day 2 was to download lots of data (big data) and stream it into Hbase. There’s a JRuby script, which I had to ...

Read More »

SQL Server Trick: Circumvent Missing ORDER BY Clause

software-development-2-logo

SQL Server is known to have a very strict interpretation of the SQL standard. For instance, the following expressions or statements are not possible in SQL Server:                   -- Get arbitrarily numbered row_numbers SELECT ROW_NUMBER() OVER () -- Skip arbitrary rows SELECT a FROM (VALUES (1), (2), (3), (4)) t(a) OFFSET 3 ...

Read More »

The Index You’ve Added is Useless. Why?

software-development-2-logo

Recently, at the office: Bob: I’ve looked into that slow query you’ve told me about yesterday, Alice. I’ve added the indexes you wanted. Everything should be fine now Alice: Thanks Bob. I’ll quickly check … Nope Bob, still slow, it didn’t seem to work Bob: You’re right Alice! It looks like Oracle isn’t picking up the index, for your query ...

Read More »

How to import CSV data into PostgreSQL

postgresql-logo

Introduction Many database servers support CSV data transfers and this post will show one way you can import CSV files to PostgreSQL. SQL aggregation rocks! My previous post demonstrated FlexyPool metrics capabilities and all connection related statistics were exported in CSV format. When it comes to aggregation tabular data SQL is at its best. If your database engine supports SQL:2003 ...

Read More »

How to Implement Sort Indirection in SQL

software-development-2-logo

I’ve recently stumbled upon this interesting Stack Overflow question, where the user essentially wanted to ensure that resulting records are delivered in a well-defined order. They wrote             SELECT name FROM product WHERE name IN ('CE367FAACDHCANPH-151556', 'CE367FAACEX9ANPH-153877', 'NI564FAACJSFANPH-162605', 'GE526OTACCD3ANPH-149839') They got CE367FAACDHCANPH-151556 CE367FAACEX9ANPH-153877 GE526OTACCD3ANPH-149839 NI564FAACJSFANPH-162605 They wanted CE367FAACDHCANPH-151556 CE367FAACEX9ANPH-153877 NI564FAACJSFANPH-162605 GE526OTACCD3ANPH-149839 Very often, according to ...

Read More »

NoSQL? No, SQL! – How to Calculate Running Totals

software-development-2-logo

If anything at all, our jOOQ talks at various JUGs and conferences have revealed mostly one thing: Java developers don’t know SQL. And it isn’t even necessarily our fault. We’re just not exposed to SQL nowadays. But consider this: We developers (or our customers) are paying millions of dollars every year to Oracle, Microsoft, IBM, SAP for their excellent RDBMS, ...

Read More »

The anatomy of Connection Pooling

software-development-2-logo

Introduction All projects I’ve been working on have used database connection pooling and that’s for very good reasons. Sometimes we might forget why we are employing one design pattern or a particular technology, so it’s worth stepping back and reason on it. Every technology or technological decision has both upsides and downsides, and if you can’t see any drawback you ...

Read More »

Seven Databases in Seven Days – Riak

software-development-2-logo

In this post I am summarizing the three days of Riak, which is the second database in the Seven Databases in Seven Days book. This post is actually in order for me to remember some tweaks I had to do while reading this chapter as sometimes the book wasn’t entirely correct. A good blog, which I used a little, can ...

Read More »
Do you want to know how to develop your skillset and become a ...

Subscribe to our newsletter to start Rocking right now!

To get you started we give you our best selling eBooks for FREE!
Get ready to Rock!
To download the books, please verify your email address by following the instructions found on the email we just sent you.

THANK YOU!

Close