Snowflake Schema: A snowflake schema is a term that describes a star schema structure normalized through the use of outrigger tables. i.e dimension table hierarchies are broken into simpler tables. In Star Schema example we had 4 dimensions like location, product, time, organization and a fact table (sales). In Snowflake schema, the example diagram shown…
Star Schema: General Information In general, an organization is started to earn money by selling a product or by providing service to the product. An organization may be at one place or may have several branches. When we consider an example of an organization selling products throughout the world, the main four major dimensions are…
What are Slowly Changing Dimensions? Dimensions that change over time are called Slowly Changing Dimensions. For instance, a product price changes over time; People change their names for some reason; Country and State names may change over time. These are a few examples of Slowly Changing Dimensions since some changes are happening to them over a…
In a relational data model, for normalization purposes, year lookup, quarter lookup, month lookup, and week lookups are not merged as a single table. In a dimensional data modeling (star schema), these tables would be merged as a single table called TIME DIMENSION for performance and slicing data. This dimensions helps to find the sales…
In a relational data model, for normalization purposes, corporate office lookup, region lookup, branch lookup, and employee lookups are not merged as a single table. In a dimensional data modeling(star schema), these tables would be merged as a single table called ORGANIZATION DIMENSION for performance and slicing data. This dimension helps us to find the…
In a relational data model, for normalization purposes, product category lookup, product sub-category lookup, product lookup, and and product feature lookups are are not merged as a single table. In a dimensional data modeling(star schema), these tables would be merged as a single table called PRODUCT DIMENSION for performance and slicing data requirements. Example of…
Dimension Table: Dimension table is one that describe the business entities of an enterprise, represented as hierarchical, categorical information such as time, departments, locations, and products. Dimension tables are sometimes called lookup or reference tables. Location Dimension: In a relational data modeling, for normalization purposes, country lookup, state lookup, county lookup, and city lookups are not merged as…
How to create Identifying Relationship with Cardinality of many to many relationship: Identifying relationship: If a foreign key column/multiple foreign key columns referencing some table, becomes a part of the primary key, and then it is an identifying relationship. Employee and PROJECTS Table association: Since the relationship is many to many with Employee_No (Employee Table)…
What is Non-Identifying relationship? If a column (foreign key) / multiple columns (foreign key columns) referencing some table becomes a column in a table as a NON-PRIMARY KEY, and then it is non-identifying relationship. How to create non-identifying relationship with cardinality of 1 to many relationship in Employee Table? Example 1: Employee Table with Department…
Xcase – Overview: Xcase is a powerful and intuitive data modeling tool. It automates database creation and maintenance, making the modeling process simple and visual. The tool provides tight support for the leading DBMS and an impressive set of capabilities. Using Xcase, data modelers can create data models from scratch or from existing databases using…
