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0answers
111 views

Kimball Cross Reference Table/Bridge Table

I'm currently struggling to understand how to apply Kimball methodology to a certain scenario and talk of Outriggers/Cross Reference/Bridge tables are starting to get confusing. Consider the scenario:...
5
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1answer
38 views

If a DW fact table is not uniquely identified by all dimensions, what problems?

This is a bit of a thought problem I've been wrestling with. I have a visceral antipathy to the notion of duplicate combinations of dimension values in a fact table. I've read a lot about the ...
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0answers
25 views

Is the modeling technique changing with column-oriented databases?

I've been working on Kimball's modeling techniques lately and he's giving directional guidance on which data belongs in a dimension and which in a fact table. But sometimes it's hard to define an ...
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0answers
55 views

Are there differences between a Fact Constellation Schema and a Galaxy Schema?

I am currently working on the two schemes and I'm just not sure if these schemes are the same or if there are differences. In the literature both are often synonymous. Now I've read that there are ...
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1answer
31 views

Is there a recommended order to create a DV model and star schema?

I want to create and implement a Data Vault Model. In the presentation layer, I want to create a View based on a star schema. Now I would like to know if there is a certain order in creating the ...
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2answers
82 views

Should I use separate address dimensions?

I have a Star Schema model with two Dimensions (User and Store) each of them have addresses, which I store. Each User and Store can just have one Address. Is it recommended to split the Dimension ...
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0answers
27 views

Dealing with Address Dimensions and composite Keys in Dimensions

I try to design a dimensional model and Im not sure If I modeled it in a correct way plus I have a Question about splitting the Store Dimension. First to the model: I have a Store Dimension (Name, ...
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0answers
29 views

Dimensional modeling and doing Sentiment analysis

I would like to try a simple Sentiment analysis with a R Script. I created a dimensional model but I'm not sure how to handle the user comments. I hope someone can give me some advices. I thought ...
3
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2answers
664 views

What are the difference between a “dimension” table in a star-schema and a “lookup” table in a relational database?

I'm trying to design a star-schema fact table along with some dimension tables that will surround it. If I reuse the natural key called customer_key in both the fact_table and dim_customer then I don'...
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1answer
124 views

Dealing with different types in a fact table

I'm working with dimensional modelling for the first time, trying to build a data warehouse that pulls in data from an OLTP database, and I'm having some trouble figuring out what to do with this type ...
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0answers
38 views

Permission error while browsing the Dimension when Dimension Security is defined on one of the attribute

I am using SSAS SQL Server for dimension modelling, and the dimension is defined as below: Dimension Name: Department Dimension Attributes: Location DepartmentCode DepartmentType I have ...
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3answers
208 views

Should a Fact table contain a column with a single unique value?

In order to simplify reporting, I am wondering if for each of the Fact tables we have, whether I can include a column that states the name of the Fact table, albeit in a more user friendly format e.g....
3
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1answer
385 views

Boolean as measure in fact table or dimension/attribute value

My fact table consists of complaints with typical dimensions of who, what and when. We have a target that the complaint should be responded to within a certain time period. I'm not sure on how I best ...
1
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1answer
215 views

Should dates in dimensional tables use dimDate?

Assuming my dimDate has a surrogate key. Should all the date columns in the dimensional tables (not the fact tables) store the surrogate key of date dimension? Or just plain date? For example, in ...
0
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1answer
307 views

Periodic snapshot fact table with monthly grain - Question on dimensions

I am fairly new to data-warehousing but have read my fair share of books and online tutorials to gain an introductory understanding of the basic components that build up a data warehouse. My end goal ...
3
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0answers
54 views

When to Converge Dimensions in a Data Warehouse When There Are Few Common Attributes

I have two StudentDetails dimension tables in my data warehouse and I want to know whether I should converge them, considering that they have limited attributes in common (keeping in mind Kimball DW ...
1
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1answer
75 views

Dimension Modelling Senario Data Warehouse Design

I'm looking for some advised on how to model the following scenario in our data warehouse. We have the following entities Staff Mobile Devices Computers Mobile Bills If feels like its simpler to ...
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2answers
1k views

Best way to capture historical changes between levels in a dimensional hierarchy

What is the cleanest way to capture changes between levels in a dimensional hierarchy? I have the dimensional hierarchy [Area] > [Region] > [Location], where Area is the parent to Region and Region ...
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1answer
1k views

SSAS Hierachies duplicates when browsing

The dimensions in the cube are giving us duplicates, there is no error while processing the cube, but when the cube is browsed we could see duplicates. There is a hierarchy in our dimension, the ...
0
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1answer
422 views

SSAS MD dimension joins to same table twice (but processing fails as attribute has 2 names for same ID)

My cube has a product dimension, and each product has an "availability" status attribute. In the database, SellableItemAvailabilityId in DimSellableItemVersion (which contains products) joins to Id in ...
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2answers
3k views

Cube with 2 measure groups (with different relationships to dimensions) returns too many dimension members in reports

I have a cube that contains stock-take data from retail operations. It has 2 measure groups - one containing the number of stock units counted in each stock-take batch (which is related to the Product,...
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2answers
366 views

Ordering of a dimension in sql server datawarehouse

Built and deployed a simple cube with a date dimension. The dimension has things like day of month. How do i sort it? it always shows in the reports as 1, 10, 11, 12, ... 19, 2, 20, 21 Design. ...
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1answer
41 views

What if the lowest granularity level can legitimately be null?

I have a normalized database that I'm going to be using as a source for a dimensional data store; one of the facts I'm collecting is Orders, the normalized schema looks roughly like this: However ...
6
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1answer
208 views

Designing a dimensional DB off a normalized source that already implements SCD's

I have built an SSIS ETL to integrate various data sources (one from MySQL, two from SQL Server) into a single SQL Server relational and normalized database, which I've called [NDS]. The SSIS ETL ...
4
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1answer
237 views

How do I make a nullable “parent” hierarchy level?

I'm setting up my first dimensional database with SSAS, and I have this [Materials] dimension that needs a hierarchy that goes something like this: [PriceCode v] --> nullable Price Code ... ...
4
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1answer
6k views

How can I get the measures of the last month with MDX?

I would like to get the values of the measures of the previous month. That's what I have: SELECT [Measures].[Recuent distinct] ON ROWS, TAIL(NonEmptyCrossJoin([Dim Date].[Calendar].[Month ...
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0answers
35 views

What Database is optimized for 4d data layout? [closed]

I need to store 4d data points inside a virtual 3d world (position+date+data value). I have a lot of data layers > 250 (wind direction, sea temperature, terrain type, etc). Sources of my data layers ...
3
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2answers
929 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
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0answers
105 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
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1answer
126 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 ...
1
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2answers
191 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 ...
1
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0answers
329 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 ...
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5answers
4k 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 ...
2
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2answers
3k views

What is the difference between bridge table and helper table in data warehouse's context?

From what I could understand :- Bridge tables are used when a dimension table can not be directly associated with a fact table. e.g. In a bank's data warehouse a fact table of balance of a customer ...
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0answers
454 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 | ...
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1answer
2k 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 ...
1
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3answers
479 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
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0answers
142 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 ...
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1answer
234 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 ...
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1answer
52 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
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2answers
234 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 = ...
8
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2answers
4k 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
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1answer
67 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
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2answers
888 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
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2answers
617 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 ...
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2answers
502 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
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1answer
627 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 schema)....
2
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1answer
2k 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 ...
3
votes
3answers
2k 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 ...
2
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3answers
1k 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 ...