Hi

I am reading about the pattern mining papers and I am confused about the horizontal and vertical database, Please someone help me give me a simple explanation of these two concepts.

MAEV

Hi,

Welcome to the forum. The short answer is:

A transaction database has two dimensions: transactions and items

In an horizontal transaction database, each row represents a transaction. Thus, a row contains a set of items purchased by a customer.

In a vertical transaction database, each row represents an item. Thus a row contains the set of transactions where the item was purchased.

An horizontal database can be converted into a vertical database, and the same can be done to convert a vertical database into a horizontal database.

Best regards,

Philippe

Could youp please elaborate it with example?

An horizontal database:

Transaction1: item1 item3 item4
Transaction2: item1 item2
Transaction3: item2 item4

The corresponding vertical database:

Item1: Transaction1 Transaction2
Item2: Transaction2
Item3: Transaction1
Item4: Transaction1 Transaction2

Both are equivalent.

In a horizontal database, the rows are transactions.

In a vertical database, the rows are items.

You meant to say, this would be the corresponding vertical database:

Transaction1: item1 item3 item4
Transaction2: item1 item2
Transaction3: item2 item4

Item1: Transaction1 Transaction2
Item2: Transaction2 Transaction3
Item3: Transaction1
Item4: Transaction1 Transaction3


Got it, Thank you so much!



Edited 1 time(s). Last edit at 10/31/2020 10:23PM by i201606.

You are welcome.