difference between peek & previous , mapping & apply map , snow flake & star schema , QV10 & QV11

[#1]

difference between peek & previous , mapping & apply map , snow flake & star schema , QV10 & QV11

[kaushiknsolanki]

Hi,

     Kindly go through the Help available with the QlikView Desktop.

     That content is the easiest to understand the different functions of qlikview.

Regards,

Kaushik Solanki

[#3]

hi please go through this for peek and previous

[#4]

hi go through this link for star and snow flake schema

Data Warehouse Schema Architecture - star schema

[#5]

hi go through this qvw file for mapping

[SunilChauhan]

peek is used to find any of the record from a table

like last and first record

previous will fetch only previous Record. see more in open qlikview and press F1.

previous(fieldName) and peek(fieldname) gives same result

mapping keyword hide the table from model

and applymap is used to merge a column on the basis of key field into other table based on mapping table

snow flake have secondary dimesions also

where as star  dimesion table are connected to fact table creating a star.

in star if you select any thing then sortest path will be apply .but in snow flake it migt be take more time to trverse as we have secondary dimesions.

star is good in respect to analysis and selections

snow flake is good for memory optimizations

hope this helps

[its_anandrjs]

Refer the below documents for the Peek and Previous and take reference from the reference manual

http://community.qlik.com/blogs/qlikviewdesignblog/2013/04/08/peek-vs-previous-when-to-use-each

Peek() vs Previous() – When to Use Each

[ashfaq_haseeb]

Hi,

Regarding Start Schema and Snowflake Schema,

Please find the document attached.

hope it help.

Regards

ASHFAQ

[manojkulkarni]

Snowflake Schema	Star Schema
Ease of maintenance / change	No redundancy and hence more easy to maintain and change	Has redundant data and hence less easy to maintain/change
Ease of Use	More complex queries and hence less easy to understand	Less complex queries and easy to understand
Query Performance	More foreign keys-and hence more query execution time	Less no. of foreign keys and hence lesser query execution time
Type of Datawarehouse	Good to use for datawarehouse core to simplify complex relationships (many:many)	Good for datamarts with simple relationships (1:1 or 1:many)
Joins	Higher number of Joins	Fewer Joins
Dimension table	It may have more than one dimension table for each dimension	Contains only single dimension table for each dimension
When to use	When dimension table is relatively big in size, snowflaking is better as it reduces space.	When dimension table contains less number of rows, we can go for Star schema.
Normalization/ De-Normalization	Dimension Tables are in Normalized form but Fact Table is still in De-Normalized form	Both Dimension and Fact Tables are in De-Normalized form
Data model	Bottom up approach	Top down approach

[#10]

Hi,

I have attached the example Qvw Of Apply map And Mapping,Peek() Function You will get brief explanation in Qlikview Help.