When building a data warehouse, it is important that primary keys of dimension tables remain stable. To accomplish this, it is strongly recommended that surrogate keys be created and used for primary keys for all dimension tables instead of using … Continue reading →
If you’ve been working with databases for any length of time, you have heard the term normalization. Normalization is the process of efficiently organizing data in a database. There are two goals of the normalization process: eliminating redundant data (for … Continue reading →
ETL is the most common method used when transferring data from a source system to a data warehouse. But there are cases where you might want to use ELT. What is the difference between the two? Read on: Extract, Transform, … Continue reading →
Do you know there are hundreds of additional tasks, tools, and components for SSIS, many which are free? Why re-invent the wheel? Take a look at this exhaustive list created by Todd McDermid on CodePlex: SSIS Community Tasks and Components. It … Continue reading →
SQL Server Master Data Services (MDS) has a number of enhancements in SQL Server 2012: Improved web user interface – If you are a current user of MDS in SQL Server 2008 R2 you know that it’s pretty difficult to … Continue reading →
SQL Server 2012 has many new security features, and three of the bigger new features are: Default Schema for Windows Groups, Audit enhancements, and User-Defined Server Roles. Default Schema for Windows Groups A database schema can now be tied to a … Continue reading →
AlwaysOn is a new integrated high availability (HA) and disaster recovery (DR) solution that provides redundancy within a datacenter and across datacenters to help enable fast application failover during planned and unplanned downtime. Specifically, AlwaysOn delivers failover cluster instances, multiple secondaries, active … Continue reading →
A factless fact table is a fact table that does not have any measures. It is essentially an intersection of dimensions (it contains nothing but dimensional keys). There are two types of factless tables: One is for capturing an event, … Continue reading →
There is an excellent site called TechNet Virtual Labs that enables you to quickly and easily evaluate Microsoft’s newest products and technologies via hands-on labs in which you are guided through the lab in about 90 minutes. There is nothing to … Continue reading →
These are my favorite SSAS white papers released by Microsoft, with many from SQLCAT. I’ll keep this post updated with new versions of the white papers as well as new ones that come along that I find useful: Analysis Services 2008 … Continue reading →
A table that does not have a clustered index is referred to as a Heap. While a lot has been written about index fragmentation and how to defrag indexes, there is not much that talks about how to defrag a … Continue reading →
If you are using Visio 2010 and creating tables via the Database Model Diagram template, you may be surprised to learn there is not a way to build CREATE TABLE scripts from your resulting diagram. The last release that supported … Continue reading →
Behind the scenes in SSIS, the data flow engine uses a buffer-oriented architecture to efficiently load and manipulate datasets in memory. The benefit of this in-memory processing is that you do not need to physically copy and stage data at … Continue reading →
Dimensions are often recycled for multiple purposes within the same database. For instance, a “Date” dimension can be used for “Date of Sale”, as well as “Date of Delivery”, or “Date of Hire”. This is often referred to as a … Continue reading →
A conformed dimension is a dimension that has the same meaning to every fact with which it relates. Conformed dimensions allow facts and measures to be categorized and described in the same way across multiple facts and/or data marts, ensuring consistent … Continue reading →
A reference dimension occurs when the key column for the dimension is joined indirectly to the fact table through a key in another dimension table. This results in a snowflake schema design. The following figure shows one fact table named InternetSales, … Continue reading →
SQL Server 2012 RC0 (Release Candidate 0), formerly known as SQL Server Denali, is now available for download. SQL Server 2012 RC0 is the first release which is feature complete. This was unexpected as no one gave any hints that it … Continue reading →
Degenerate dimensions, also called fact dimensions, are standard dimensions that are constructed from attribute columns in fact tables instead of from attribute columns in dimension tables. This is because useful dimensional data is sometimes stored in a fact table to … Continue reading →
In SSAS, data structures do not always conform to the snowflake or star schema model where one fact is associated with a single dimension member. For example, consider the example of financial transactions in accounts that can have one or … Continue reading →
Parallel execution in SSIS improves performance on computers that have multiple physical or logical processors. To support parallel execution of different tasks in a package, SSIS uses two properties: MaxConcurrentExecutables and EngineThreads. If you are like me, you probably did not … Continue reading →