OLAP is a advance technique that are used for data storage in database with
multidimensional method, The accessing speed of OLAP is faster that OLTP
or operational database. OLAP is basically used for fast saving and accessing
data from database with different view of point.
There are mainly 3 types of OLAP-
1. Relational OLAP(ROLAP)
2. Multi-dimensional OLAP(MOLAP)
3. Hybrid OLAP(HOLAP)
we discuss each type in detail as fallows-
1. Relational OLAP (ROLAP)-
That method is used for data saving and data accessing from database
mainly. In ROLAP SQL reporting tool are used for extract data directly from
data warehouse. In that method use slice and dice method for data
accessing from data warehouse. Most of “where” clause are used in that
method. It is more scalable for handling large amount of data. In that handle
numerical and textual data. ROLAP application display slower performance
as compare other MOLAP tools. That tool is suitable for large or complicated
calculations because of query language are used.
Advantages of ROLAP-
1. It can handle large amount of data.
Dis-Advantages of ROLAP-
1. Performance can slow.
2. Limited by SQL functionality.
2. Multi-Dimensional OLAP (MOLAP)-
, It is a advanced technique in OLAP. In that type data can be saved in
database in the from of multi-dimensional cubes with array based structure.
Because of data saved multidimensional the data will fetch up or access
fastly with user requirement as compare ROLAP.
That is the best tool for create analytical report. the dimensions of cubes are
rotate with user requirement mainly-this is done by slice and dice technique.
MOLAP are used for complex calculation. There are some limitations of
MOLAP is they are less scalable(Accuracy) as compare ROALP. MOLAP also
handle limited amount of data.
Advantages of MOLAP-
1. Excellent performance.
2. Can perform complex calculations.
Dis-Advantages of MOLAP-
1. Limited amount of data handled only.
2. Require additional investment.
3. Hybrid OLAP (HOLAP)-
Hybrid OLAP is the combination of ROLAP and MOLAP in single architecture.
It is a bridge between traditional techniques to advanced technique. Hybrid
are used both ROLAP and MOLAP methods for storing data in well manner. It
store large data in ROLAP and complex calculations in MOLAP.
Advantages of HOLAP-
1. Better scalable.
2. Handle large amount of data and complex calculations.
Dis-Advantages of HOLAP-
1. As slow as ROLAP when you try to access leaf level data.
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