Derik Hammer

Posts by: Derik Hammer

Amazon Redshift Unexpected Commit

Amazon Redshift Unexpected Commit

If you are familiar with sqlhammer.com, then you know that I heavily specialize in the Microsoft Data Platforms. My experiences with Microsoft, and specifically the SQL Server products, established an expectation that explicit transactions would always commit/rollback successfully or there…

NYC Yellow Cab Data in Azure SQL Data Warehouse

NYC Yellow Cab Data in Azure SQL Data Warehouse

Microsoft Azure provides a convenient feature when creating a new Azure SQL Data Warehouse database. You can create the database from a backup of the Microsoft sample database, AdventureWorksDW. This is super fast and easy. It also has huge tables…

Active Forgiveness

Active Forgiveness

Earlier this year, I wrote about Failure Integrity Power Transparency and Respect. This was taken from the perspective of a person who is learning how to navigate their failures or the failures of a group which includes them. In this…

SQLHammer in 2018

SQLHammer in 2018

SQLHammer.com has been quieter than usual this year. I have not written nearly as many blog posts as I would like. The reason for this is because I have been very busy and I thought it was time to update…

Tell me your problems

Tell me your problems

I need your help. I am working on improving my department’s problem solving skills. This is going to manifest in a lot of one-on-one mentoring, team exercises, and formal presentations. The formal presentations I am going to build into sessions…

Failure Integrity Power Transparency Respect

Failure Integrity Power Transparency Respect

The key to success is failure. There is much truth in that statement. It is also like a prism which can be perceived differently from many different angles. One angle is to say that, the difference between a successful person…

Transact-SQL STRING_AGG

Transact-SQL STRING_AGG

Creating comma separated strings from a column, or delimited strings as I like to call it, is a very common problem in SQL. Beginning with SQL Server 2017 and Azure SQL Database, there is now another option to the existing…

Amazon Redshift Temporary Tables

Amazon Redshift Temporary Tables

My company is in the middle of a migration to Amazon Redshift. Data warehouse design standards have been in question now that our platform is changing. One development team asked me whether they would be allowed to use temporary tables…

Linked Server Elimination

Linked Server Elimination

SQL Server has a feature for partitioning tables and indexes. Partitioning can be implemented at many levels, however. You can create multiple tables for one logical data set, you can split the set into multiple databases, and you can even…

What is a data lake?

What is a data lake?

Our zatz-its are wise. Our zatz-its are dispersed. We have questions to ask the zatz-its, so we corral them in a warehouse. Now everyone can see the zatz-its and ask any question that the zatz-it can answer. But buyer beware,…