Book Image

Microsoft SQL Server 2012 Integration Services: An Expert Cookbook

Book Image

Microsoft SQL Server 2012 Integration Services: An Expert Cookbook

Overview of this book

SQL Server Integration Services (SSIS) is a leading tool in the data warehouse industry - used for performing extraction, transformation, and load operations. This book is aligned with the most common methodology associated with SSIS known as Extract Transform and Load (ETL); ETL is responsible for the extraction of data from several sources, their cleansing, customization, and loading into a central repository normally called Data Warehouse or Data Mart.Microsoft SQL Server 2012 Integration Services: An Expert Cookbook covers all the aspects of SSIS 2012 with lots of real-world scenarios to help readers understand usages of SSIS in every environment. Written by two SQL Server MVPs who have in-depth knowledge of SSIS having worked with it for many years.This book starts by creating simple data transfer packages with wizards and illustrates how to create more complex data transfer packages, troubleshoot packages, make robust SSIS packages, and how to boost the performance of data consolidation with SSIS. It then covers data flow transformations and advanced transformations for data cleansing, fuzzy and term extraction in detail. The book then dives deep into making a dynamic package with the help of expressions and variables, and performance tuning and consideration.
Table of Contents (23 chapters)
Microsoft SQL Server 2012 Integration Services: An Expert Cookbook
Credits
Foreword
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

The Expression Task


The Expression Task is one of the SSIS Control Flow Tasks. The reason why we excluded it from Chapter 2, Control Flow Tasks, is that this task works only with expressions and variables and is much more relevant to this chapter.

The Expression Task provides a way of setting a variable's value with an expression. This is a handy task and was added recently in SSIS 2012. Besides the fact that this task didn't exist in the previous versions of SSIS, there was an alternative solution for same cases, which is used frequently.

In this recipe, we will create a filename based on the date of running the package and combine it with a folder path to create a full file path.

How to do it...

  1. Create an SSIS project and name it R04_Expression Task.

  2. Add two variables to the package scope as shown in the following screenshot:

  3. Drag-and-drop an Expression Task into Control Flow and double-click on it.

  4. Add the following expression in the Expression Builder window of the Expression Task Editor, as...