What is a star schema? A star schema is a database schema used to store data in a star format. This schema consists of a central table, called the “fact table,” and a number of directly connected other tables, called “dimension tables.” The fact table contains information about metrics or measures, while the dimension tables contain information about descriptive attributes. The star schema is very simple and easy to understand, making it ideal for cloud data warehousing and business intelligence applications. What is a snowflake schema? A snowflake schema is a type of database schema that is used to store data in a more… Read more
Category: MSBI
SSIS – Non Blocking , Partially Blocking and Full Blocking
Data flow transformations in SSIS use memory/buffers in different ways. The way transformation uses memory can impact the performance of your package. Transformations memory/Buffer usage are classified into 3 categories: 1.Non Blocking 2.Semi Blocking 3. Full Blocking All the dataflow components can be categorized to be either Synchronous or Asynchronous. Synchronous vs Asynchronous : Synchronous components The output of an synchronous component uses the same buffer as the input. Reusing of the input buffer is possible because the output of an synchronous component always contain exactly the same number of records as the input. … Read more
SSIS Data Flow Tasks with Descriptions
S No Transformation Description 1 Aggregate Summing / Averaging a total of the products purchased by a customer online to produce the final amount. 2 Audit When you want to load audit information like (Created Date, UserName , server Name..etc) to your Destination table. 3 Character Map String Manipulation, like Lowercase, Uppercase etc.. 4 Conditional Split When you want to split your data to many destinations based on conditions. 5 Copy Column To have same column data with alias name 6 Data Conversion To convert the data type, (Unicode String àString…) 7 Data Mining Query Evaluating the input data against… Read more
SSAS STORAGE MODES
In SQL Server Analysis Services 2008, we have three storage mode options available to us: Relational Online Analytical Processing (ROLAP), Multidimensional Online Analytical Processing (MOLAP) and Hybrid Online Analytical Processing (HOLAP). There are advantages and disadvantages to each, so I figured I’d take a few minutes to give a quick overview describing the storage modes and laying out some of the pros and cons of each. Relational Online Analytical Processing (ROLAP) The ROLAP storage mode allows the detail data and aggregations to be stored in the relational database. If you plan on using ROLAP, you need to make sure that… Read more