The DBA's Role within N-tier Applications Presented by: Dan Andrews Time: 10-15 Minutes Slides: 8 Thank you all for coming out tonight, there’s this whole baseball game thing happening and some other sport with an orange ball also happening a few miles away.

Who the heck is this guy? Dan Andrews I work at TMW Systems as a Database Architect and/or Platform Engineer depending on who you ask. I have been with TMW Systems since June 2016. Previously with PNC Bank as a Senior Software Engineer in QRM (Quantitative Risk Management) area. Previous to PNC, at Kenan Advantage Group as a Lead Software Developer and Database Architect. Blog: http://www.medinafreemason.com Twitter: https://twitter.com/MedinaFreemason LinkedIn: https://www.linkedin.com/in/dandrews330 Stackoverflow: http://http://stackoverflow.com/story/dandrews330 Email: dandrews216@gmail.com I know Mindy too! Somewhere, there’s a guy receiving my bio multiple times wonder what the heck is going on. END: Please don’t wait until the end for questions. I have the attention span of a gnat, and when I’m at a presentation, I usually forget to ask my questions at the end. So, get my attention and ask away. How many people here are developers? How many work with enterprise applications? Okay, let’s consider a simple application., the worse case application for enterprise solutions

The strawman that got into production An example of an application with little to no design intent, is the strawman that got into production. This the application that reads directly into the database with its own connection string. It concatenates strings to build SQL queries. It has no regard to indexes or any knowledge of efficiently accessing the database. It doesn’t utilize or rarely utilizes existing stored procedures – only the stored procedures that the developer knows of at that moment. It cannot utilize stored procedures made after the fact w/o a recompile and deployment. It’s the application that users complain is too slow while DBA involvement was an after thought. Only after the application is written, rolled out, and people are complaining does a DBA get tasked with making indexes and reviewing the data model. What’s worse? The salesman started selling this application as a solution for customers and claimed that it’s second only to sliced bread. We’ve all been here, we’re not alone, there should be a support group for us.

What is N-Tiered Architecture? This is the minimum requirement for MVC

Enter the Service Layer

Don’t get too cra-cra

Why do we need a service layer? Generally the data access layer is tightly coupled with your RDBMS. Adding a service layer allows you to abstract the RDBMS and allows you to use multiple data sources or change your data source w/o affecting down stream application. This allows you to have the best of both worlds and utilize document-oriented database such as MongoDB, Couchbase or other NoSQL database systems. A Service Layer creates a reusable code for other applications with a single entry point. Stored Procedures (CRUD layer) are great, but that new hire just found how to insert data directly, skip all of the triggers, the application is fast, salesmen & managers are excited, and the developer just became the Rock Star of the company, hailed as an Elite Developer by your boss. Service layers allow DBAs do what DBAs do well, to monitor query performance, to write efficient stored procedures for the data model, and maintain a realistic number of indexes for the tables. They allow DBAs to worry less about the one off queries. TL;DR: Service Layers allow you to abstract the data access layer I can make a NoSQL for SQL Server DBAs presentation if it would be popular, see me after or email me.

What does the N-Tier approach promise? DBAs want to be part of every design aspect of an application We want to design the data model We want to have the application developers change their code We don’t want some code monkey touching our beloved stored procedures (I’m a code monkey) These goals are generally unrealistic as there are more developers than DBAs. Developers will wear down DBAs by flooding them with code changes causing a DDoS. By utilizing an N-Tiered approach, DBAs get to focus on the database and data model. Developers don’t feel like DBAs are out to make their lives miserable. Applications consume objects from the Service Layer without having to worry about how’s to get the data.

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