What is a data mart?

The other notion that the Inmon school of thought disproved was the notion that a DM could be turned into a DW when it reached a certain size. This was a false claim as the core misconception was that a data mart and a data warehouse could be used as substitute goods; along with being complementary goods. In several cases, this can be a difficult distinction to make; however it is essential to determine the difference in this particular case. To discredit the notion, Inmon used another analogy when he said, “This is no more valid than saying that when a tumbleweed grows large enough that it can be turned into an oak tree. Reality and genetics being what they are, it is true that a tumbleweed and an oak tree are, at one point in their life, green living organisms planted in the soil and are approximately the same size. But just because those two plants share a few basic characteristics at some moment in time does not mean that a tumbleweed can be turned into an oak tree.” Therefore, no matter how many characteristics they have in common, data marts and data warehouses will always be different. They can not be used interchangeably, and it’s only when they’re paired together that they operate at their optimal potential.