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:
CHARACTERISTIC of OLTP
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
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
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CHARACTERISTIC of OLAP
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
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
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Some more information on this topic can be found here.