In my previous blogs I was discussing about ETL concepts and tools. Predominantly they are used to move the data from OLTP to an OLAP system. So what is this OLTP and OLAP and why do we need to move the data between them. Here is my thought on it.

OLTP System deals with operational data. Operational data are those data  involved in the operation of a particular system.

Example: In a banking System, you withdraw amount through an ATM. Then account Number,ATM PIN Number,Amount  you are withdrawing, Balance amount in account etc are operational data elements.

OLAP deals with Historical Data or Archival Data. Historical data are those data that are archived over a long period of time.

Example: If we collect last 10 years data about flight reservation, The data can give us many meaningful information such as the trends in reservation. This may give useful information like peak time of travel, what kinds of people are traveling in various classes (Economy/Business)etc.

The biggest difference between an OLTP and an OLAP system is the amount of data analyzed in a single transaction. Whereas an OLTP handles many concurrent users and queries touching only a single record or limited groups of records at a time, an OLAP system must have the capability to operate on millions of records to answer a single query.The following table summarizes the differences between OLPT and OLAP:

System scope/view            Single business process (Operational: ERP, CRM)
Data sources                     One
Data model                        Static
Dominant query type           Insert/update
Data volume per transaction Small
Data volume                       Small/medium
Referesh                            Immediate
Bulk load/insert/update       No
History data                       Not available
Response times                < 1 second
System availability            High “24/7”
Typical user                      Front office
Number of users               Large
What is the Salary of Mr.Shyam?
What is the address and email id of the person who is the head of science department?

System scope/view          Multiple business subjects (Decision Support System)
Data sources                   Many
Data model                      Dynamic
Dominant query type        Read
Data volume per transaction    Big
Data volume                    Large
Referesh                        Periodic
Bulk load/insert/update    Yes
History data                   Available
Response times             Can be in minutes
System availability          Relaxed “8/5”
Typical user                    Managers/ Executive
Number of users              Small/medium
How is the profit changing over the years across different regions ?
Is it financially viable continue the production unit at location Dwarka?

Some more information on this topic can be found here.


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