In this post, we are going to learn how we can get hierarchical data in order. We are dealing with a user defined hierarchical data which can have “n” number of siblings and their siblings can also have “n” number of siblings in turn. For demo purpose, we have a Product_Master table, in which a product can be marked as a parent […]
We have explored Junk dimension and Degenerate dimension in previous posts, now we are going to discuss Role playing dimension in this post. Lets start with the definition followed by an example. Role playing dimension A fact table keeps the facts of a business process. It is built of two types of columns: measure columns and dimension key columns. Measure are the quantitative business data
We have discussed the use of junk dimensions in data modelling and in this post we are going to explore Degenerate dimension. Lets start with the definition. Degenerate Dimension A high cardinality attribute column in the fact table which does not have any other content except its natural key and is required as a dimension for analysis or
Now that you are familiar with database concepts and SQL Server Management Studio, it is time to begin our journey with T-SQL programming. In my opinion, to shine as a good T-SQL programmer, one must have a good understanding of T-SQL concepts and its capability. In this chapter “Create, Alter and Drop – Database and Table”, we are
What is a Junk Dimension? Have you ever come across a scenario where many small dimension tables connect (using foreign key) to the fact table? In data warehouse, we have two types of tables, Fact and Dimension. Fact table contains business facts as measures and references to the dimension tables. Dimension tables have attributes which contains textual information of business facts and
In this SQL Server Tutorial, we have gone through DBMS, RDBMS and SQL Server, Table Relationships, Data Integrity, Types of keys and Database normalization chapters. Now that we have a good understanding of database concepts, it is time to put our feet in T-SQL. Before we begin our journey with T-SQL (MS SQL Server programming language) we need to be familiar with SQL Server Management Studio, also
In this post, we are going to generate serial number for each consecutive set of numbers in a given column. We have a table tbl_Donation with columns EmpId and DonationYear. For each consecutive set of years of each employee, we need to generate serial numbers. If employee “X” donated in 2006, 2007 and 2008 years consecutively and
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In previous chapter, “Types of keys“, we had a good discussion on keys and their types in SQL Server. In this chapter “Database normalization”, we are going to discuss database normalization process and normal forms. Lets start our discussion with definition of Normalization. Normalization Normalization is a process of minimizing redundant data from database by decomposing the columns of a table
What is the default length of CHAR, NCHAR, VARCHAR and NVARCHAR when we don’t specify their length in their length argument? If we omit the size of CHAR, NCHAR, VARCHAR and NVARCHAR, how they behave? In this post “CHAR, NCHAR, VARCHAR and NVARCHAR default length”, we are going to discuss the default length of CHAR, NCHAR, VARCHAR and NVARCHAR data types,
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In previous chapter, we had a good discussion on “Data Integrity” and in this chapter “Types of Keys”, we are going to discuss Keys and their types in SQL Server. Lets start this topic by defining keys”. What is Key? Keys are fields in a table which participate in below activities in RDBMS systems: To
