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2
votes
2answers
32 views

When to choose an attribute vs. a new dimension?

I am fully aware of what is a fact, attribute and dimension. However, I'm quite confused to which traits I should choose for dimensions vs attributes of that dimension. For instance, I'm building a ...
2
votes
0answers
20 views

Column Store Indices versus Dimensional Tables

I have a Data Warehouse and want to think ahead one year when I may get a database update allowing me to use column store indices. My dimensional tables are mostly junk dimensions containing columns ...
2
votes
1answer
26 views

Duration measure in fact table

I have a fact table with the user reservations with StartDate and EndDate. I am thinking what is the proper way of serving the duration queries in the reports. Should I calculate DurationDays and ...
0
votes
1answer
13 views

Dimensional Model for inheritance in dimensions

How are dimensions typically modeled in a dimensional model if one dimension logically inherits from another dimension? For example, assume I have an Employee dimension and a Driver dimension, where ...
0
votes
0answers
37 views

ETL flow in Fact tables

I've got a simple theoretical question... If we discuss the principles, elements, design and implementation of a typical ETL flow for a dimension table then, in my understanding, (in short) I'd say ...
1
vote
1answer
153 views

Dimensional Modeling and ETL in Redshift

I have been researching Amazon's Redshift database as a possible future replacement for our data warehouse. My experience has always been in using dimensional modeling and Ralph Kimball's methods, so ...
0
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0answers
40 views

Oracle MODEL clause: Carry yesterday's leftovers to today

I'm new to the MODEL clause. I'm trying to track volume of worked/unworked to-do items over time. What I HAVE is: work_date born (# of new to-dos per date), robo (# of computer-closed to-dos ...
0
votes
0answers
63 views

Converting Entity Relation(ER) Model to Relational Schema?

I have the following ER Model I am trying to convert this to a relational database schema but I am not sure about several things: PORT_VISIT and PORT are weak entities. How do I figure on which ...
1
vote
0answers
62 views

how many fact tables do I need given I want to build an OLAP for Quotation Line Item and Purchase Order Line Item report?

My client wants a report that looks something like this on a daily basis. +---------------+-------------------------+-----------------+---------------------+-------------+ | ProductNumber | ...
0
votes
1answer
113 views

What to do when facts change frequently in a star schema for data warehouse?

I have a Quotation Management system that I built as a CRUD web app. Over time, I realized I need to improve it so that management can have their reports. Hence I studied the Kimball method of data ...
0
votes
0answers
90 views

Fact table linked to Slowly Changing Dimension

I'm struggling to understand the best way to model a particular scenario for a data warehouse. I have a Person dimension, and a Tenancy dimension. A person could be on 0, 1 or (rarely) multiple ...
1
vote
3answers
76 views

Data Warehouse measures without a corresponding dimension

I have an operations database that contains this table: salesQuality salesPrice salesCategory According to my business requirements, the salesQality and salesPrice are measures. However, ...
0
votes
0answers
64 views

Which is the best way for selecting dimension attributes while creating a dimension?

I'm a newbie to SSAS OLAP so please apologize me if it was a silly question but surely I need suggestions. I would like to make clear some concepts which was confusing for me. Let us consider five ...
1
vote
1answer
67 views

Should I create a Factless Fact Table or Denormalise my table

I am creating a data warehouse from a store database and I have a question regarding the design of my dimensions and facts. In the store database a table exists for Person, Person_Address and ...
0
votes
1answer
25 views

Conformed Fields or Snowflake? - Shop and Customer Location

I have shop dimension and customer dimension which both has location information. Should I create location dimension to correlate shop location and customer location? I believe this one is called ...
1
vote
2answers
50 views

Dimension for Product Properties based on Product Type - Sparse Dimension?

I am creating dimension of product properties for sales facts. Property of product depend of product type. For example: - Type = smartphone. Properties = model, OS, size - Type = book. Properties = ...
7
votes
2answers
1k views

Is my understanding of Fact table granularity correct?

Myself and another DBA at our company are tasked with reviewing a database design that a vendor has developed for us. The vendor has said they use Kimball as the basis for their design. (NOTE: I am ...
2
votes
1answer
43 views

Modeling Conversion Events in a Data Warehouse

How should I model conversion events? For instance, if a sales opportunity goes from "stage: prospecting" to "stage: validating", should that be treated as a changing dimension, or a conversion event ...
1
vote
2answers
172 views

Business Logic in Data Warehouse

my question is: Should business logic be stored in the data warehouse data store? Or should it only exist in the reporting applications? To give a more concrete example: In the CRM operational ...
0
votes
2answers
157 views

Database design for tracking referral dollars and referred dollars

Dropbox has a great referral incentive program that gives a storage bonus based on whether a person is referred to Dropbox or refers others to Dropbox. What data base design is good for managing ...
1
vote
2answers
213 views

Dimension or Degenerate Dimension?

I am taking a course on data warehousing. Currently, I am reading through Ralph Kimball's Data Warehouse Toolkit. I understand that a degenerate dimension is a dimension key that is stored in a fact ...
0
votes
1answer
261 views

Constellation Schema; Relationships between fact tables

What are acceptable types of depedendcies between facts in a multiple-fact schema? Conceptually talking, As you know a Multi-Dimensional Model may have multiple facts (like in a constellation ...
2
votes
1answer
674 views

Dealing with measure groups of different granularity

Let's say I have a simple data warehouse with the following fact tables: FactPurchase: one row per property purchased, with purchase amount, value, etc. FactMonthlyStatus: one row per property, per ...
1
vote
2answers
439 views

To normalize or not to normalize for few distinct values

Assuming in a Postgres database, you have a table called party, which can have less than 5 well-defined party_types such as 'Person' or 'Organization'. Would you store the party_type in the party ...
1
vote
3answers
324 views

How to solve multidimensional data relationship

I'm having a problem, that I could solve programmatically, but for my personal (test) project I'm trying to see if I can fix it in the relational model. Imagine a complex fashion product Pants with ...
0
votes
0answers
148 views

Datamodel design for multiple roles, country access

I am in the process of creating a data model for the below scenario there will be two hierarchies a) dept hierarchy (emp -> team -> dept -> branch) b) sales hierarchy (emp -> marketing manager -> ...
0
votes
1answer
262 views

Type of Foreign Keys for a Dimensional Model Fact Table?

I've been reading about dimensional models, and in particular fact tables, but I haven't really seen one in action (i.e. the actual content), just diagrams of the table structures and column names ...
1
vote
1answer
615 views

Modeling staff dimension in data warehouse

I need to write a data warehouse diagram. I've got a problem with staff area. I have to store a information about workers details like name, age etc., and workers job time and agreement details like ...
0
votes
1answer
177 views

BI development in Microsoft BI

I need to learn how to create a dimensional modelling for an organisation that do not has a BI tool and BI model. Where can I learn more about BI development that should be used in a company? IT's ...
4
votes
3answers
5k views

Datawarehouse Design: Combined Date Time dimension vs. Separate Day and Time dimensions and timezones

We are just starting design for a new data warehouse and we're trying to design how our date and time dimensions will work. We need to be able to support multiple timezones (probably at least GMT, ...