Data blending is the combining of data from two or more different sources. We can combine the data between two sources, such as Oracle, SQL Server, Excel, and others.
Consider the admission data given in a relational database and the admission target data given in an Excel spreadsheet. Now, to compare the actual admissions with the target admissions, we can perform data blending. Here, we will blend the data based on some common dimensions of both sources to access the measure of the Admissions target. We list the two sources involved in data blending as the primary and secondary sources of the data. A left join is performed between the primary data source and the secondary data source, wherein all the data rows from the primary data source and only the matching data rows from the secondary data source are fetched.
Each data source in data blending includes its own collection of dimensions and measures. Data blending is useful when combining data from a variety of sources.
Data joining, on the other hand, is also combining data but from two or more tables or sheets within the same data source.
Combining two tables from the same SQL Server or Oracle Database or DB2 or any other data source. Combining two worksheets or more in the same Excel package will also fall under data joining.
Data joining is useful when combining data from a single source with several tables, sheets, or others.