high cardinality

[Former Member]

hi,

     sorry for asking basic question

    i know about line item if dim table is more than 20% fact then search because of which char tha table size increased and make it as line item dimention

    and my doubt comes here wat is meant by cardinality is dat the total records in a dimention table????

    i am rele sorry for asking basic questions plz plz plz do reply me

[Former Member]

Hi Vekatesh,

Lets take simple example you have 100 records in one dimension table.

Cardinality: This is percentage unique no of records of total no of records.

Now think about i have 100 records in dimension which has "Marital Status" field. In this case max we can have 3 unique values(Single, Married and Widow), so cardinality is LOW.

Now say I have 100 records in dimension which has "sales order' field. In this case obviously 100 records will be unique, so it is called HIGH cardinality.

If don't use system maintains BITMAP indexes and If we select HIGH Cardinality then system maintains B-Tree indexes which is faster than BITMAP.

Regards,

Venkatesh

[former_member210724]

Hi,

Cardinality: .Cardinality refers to the number of distinct values in a column in relation to the total number of rows.

High Cardinality: High Cardinality means that this dimension contains a large number of

distinct characteristic values.Example  : document number....

Low cardinality: It means this characteristic contains less number of values,For example, imagine a column with only two values like Statu: True or Flase...Sex: Male or Female

Regards,

Anand.

[Former Member]

http://scn.sap.com/community/data-warehousing/netweaver-bw/blog/2011/04/16/short-note-on-line-item-a...

Regards,

Sushant