topic Re: Concatenate vs link table in App Development

Concatenate vs link table

egodinho — Wed, 29 Nov 2017 15:07:01 GMT

Good afternoon,

I am developing a data model and I ask the second one:

I have three tables of facts many different fields and the same dimensions.

Example:

Fact1:

Dim1

Dimi2

Measure1

Measure2

Measure3

Measure4

Measure5

Measure6

Fact2:

Dim1

Dimi2

Measure1

Measure2

Measure3

Fact3

Dim1

Dimi2

Measure1

Measure2

Measure3

Measure4

Measure5

Measure6

Measure7

Measure8

Measure9

Measure10

Measure11

Measure12

Measure13

Measure14

Measure15

Measure16

What is the best choice? Conactenate or linktable?

Using concatenate I get a single table with multiple fields with null values.

What is the impact of having multiple fields with null values in the table?

Best regards.

Élio Godinho

Re: Concatenate vs link table

Anonymous — Wed, 29 Nov 2017 15:16:12 GMT

I always use concatenate where viable. Generally it results in far better performance.

You will by definition end up with the nulls you mention, but this should [hopefully] not cause any showstopper issues.

What I also often do is is add an extra field called Source and put into it the some text that identifies which source table that data came from, as sometimes that is need for Set Analysis in some use cases and can useful for diagnostics as yo can see what data came from where.

Have tried the concatenation ?

If so, did it work ok for your use case ?

Re: Concatenate vs link table

egodinho — Wed, 29 Nov 2017 15:24:02 GMT

Hi Bill,

Thanks for the quick response.

I have not tried it yet

Regards,

Élio Godinho

Re: Concatenate vs link table

0li5a3a — Thu, 30 Nov 2017 14:08:16 GMT

Hi ,

I recommend to concatenate the tables.

Regards,