Questions tagged [data-warehouse]
A database system optimised for reporting, particularly in aggregate. Often, but not always implemented using a star schema.
394
questions
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text unique to the grain should be stored in fact table or dimension table?
I am modeling a star schema for user reviews using the yelp data set.
Each user review has a business dimension key, user dimension key and a bunch of data associated with the review. All of the ...
0
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1answer
23 views
Data modeling for Warehouse
I am learning about database warehouses and data modeling. I came across this blog post. In the section, "DIFFERENT MODELS HAVE DIFFERENT PURPOSES" the author mentions that depending upon ...
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1answer
27 views
SSAS error deploying project: Ensure that 'SQL Browser' service is running
After successfully building my project, I got this error when deploying it:
The project could not be deployed to the '\SQLEXPRESS' server because of the following connectivity problems :
A connection ...
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0answers
33 views
Schema and/or reporting SQL for customer acquisition cost?
This a design question around creating fact/dimension tables to query customer acquisition cost and how to properly model the tables and query them.
Business Rule
We spend some money per day per ...
0
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1answer
18 views
Leaf Joins in Data Warehouse Design
Upon modeling my very first data warehouse model (for historical stock market data), I stumbled across a data relationship that I don't know how to best account for. The fact tables include multiple ...
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1answer
51 views
Best Practice for Handling Table with Large Amount of Transaction Data
I have a transaction table storing large amount of transaction data. Only the most recent data of one month are required to be available for transactional use in real-time. Less recent data may only ...
0
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1answer
48 views
Replicating PostgreSQL data into Citus/Greenplum?
I need to integrate data from 3 different PostgreSQL databases (OLTP application backends) in a data warehouse. For the data warehouse itself I consider using Citus or Greenplum. There is a ...
1
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2answers
38 views
best approach to model relation between customers - dimension dim_customer (SCD2) which can be a HEAD/SUB customer
Hi there we have the concept of having department. each department can either be its own head or it can have a head department. (similar to each person in a organisation is a employee but some ...
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1answer
35 views
How can Amazon Redshift be built based on PostgreSQL if Postgres is row-based?
According to Amazon, Redshift is based on PostgreSQL, and is a column-oriented database management system. This looks to me as a very self-conflicting statement, isn't Postgres a row-oriented database?...
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19 views
How are the relations from Relational Database mapped to DataWarehouse?
this year one of our collage courses was related to creating and managing data warehouses. There is one thing that I really struggle to understand and I would appreciate any kind of advice that you ...
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0answers
38 views
Flags Cloud SQL for Postgresql
Context:
I have a process that runs daily, with different amounts of data, if the process is on the weekday (process last 30 days), for weekends (process last year). The input is of 10 tables of ...
2
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1answer
38 views
What are the disadadvantages of a datawarehouse with no datawarehouse tables, but only datamarts?
The ETL design pattern prescribes transformation from staging tables to a central data warehouse data model, followed by extracting data from the data warehouse data model to data marts.
Are there any ...
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22 views
Distinguishing between fact and dimension tables in data warehouse
Is it true that facts in a fact table of a data warehouse always have a relation to time? I.e. is it true that a fact must always be assignable to a specific point in time?
If this is correct, can we ...
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24 views
db choice for activity log
I'm working on a geo-replicated web platform, composed of an ecosystem of microservices.
We need to improve and rework the user activity tracing pipeline and I'm looking for "the best" ...
3
votes
2answers
254 views
Consistent data in dimension and fact tables from multiple incrementally loaded staging tables
To create a data model for our data warehouse we use tooling supplied by the ERP vendor. This does probably matter due to the fact that is has it's limitations. We inherited this environment with a ...
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0answers
12 views
Copy DWH for reports
I have a heavy load DWH server.
I wish to create a copy of that server for report purposes (Cognos reports to be exact).
In today's situation I have many reports and can cause locks on other processes,...
0
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1answer
247 views
How to Store a Many-to-Many Relationship Between Fact Tables in a Data Warehouse
What are some structures and models to store many-to-many relational data between two fact tables in a data warehouse? Currently, I am using a mapping table which includes the primary keys from both ...
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27 views
How to deal with equally growing fact/dimension tables in datawarehouse design?
I have a source data set with:
customer
customer_product_purchase
customer_support_plan_purchase
customer_support_request
All of them have a relationship such that a support request is raised ...
0
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0answers
40 views
Oracle - SCD Type 2
I am new to Oracle
I have 2 tables called
dwh_tbl_dim_supplier_type2_ar (target table)
stg_tbl_dim_supplier_ar (source table)
dwh_tbl_dim_supplier_type2_ar contains 6 column
SUPPLIER_KEY (PK)
...
0
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0answers
53 views
How to correctly define foreign keys to heterogenous dimensions in fact table?
Question
What is the best practice for defining foreign keys in a fact table to multiple different and mutually-exclusive dimension tables?
Example Case
Business process
I am creating a ...
0
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1answer
27 views
Deciding what values should be used in a data warehouse dimension?
I'm beginning to look at data warehousing and I'm coming across examples where, for instance, we have check payment transactions. I understand that this should be the "fact" and we would have ...
0
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1answer
24 views
In a data warehouse, should a measure be based on a fact or a dimension?
Let's say there is a data warehouse created from a shop data. A fact is a single purchase of a product. There is a dimension that describes a customer.
There is a need to create a measure that ...
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0answers
24 views
Implementing data warehouse on the cloud [closed]
I need to implement a data warehouse on the cloud for a mid-sized company. The database size will be around 200 Gb.
My options are (so far):
AWS with its database Redshift
Azure with its database ...
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0answers
17 views
Trying to do a fact and dim table in Sql
so far this is what i have code wise, but im getting an error 1239 . Is it not referencing something correctly .
CREATE TABLE CustomerDim
(
C_CustomerID_Cu INT(10) NOT NULL,
...
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0answers
116 views
Star schema with both many-to-many relations and inheritance
The problem
I am trying to make a star schema of the following situation, concerning transactions on a stock market. I have summarized the scenario here:
Each transaction traded on the market has
1 ...
2
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2answers
94 views
Handling Big Data
I have a MySQL database that will have 2000 new rows inserted / second. These rows indicate the value of a sensor at that particular moment.
The plan is to get this data into graphical ...
2
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0answers
51 views
Store email in a separate Dimension or in a Degenerate Dimension?
I just started learning about dimensional modeling and I am creating a star to analyse email newsletter signups for an online business.
I have a fact table that records the signups and links to a ...
0
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0answers
22 views
implementing one to many relation between 2 dimensions in dataware house
I am designing a Dataware house for the Stackoverflow job section. I have two dimensions: job opportunity and company. every record of job opportunity is referenced to only one record of company ...
1
vote
2answers
145 views
Strategies/Resources for implementing data lineage in an ETL process?
I'm struggling to articulate my need here.
I've been tasked with developing a significant ETL process dealing with warehouse item costs in a major grocery chain using the full Microsoft Stack.
I'd ...
3
votes
1answer
729 views
What's the best way to concatenate a multi-column foreign key?
We are expanding our data warehouse to include a new source system. In the new system, we want a single column for a primary key, but in the old system it's two columns.
For exmaple:
create table #...
1
vote
2answers
50 views
How does Data Warehousing work in reverse? [closed]
I've made many researches about data warehousing to learn more about it and I think I've grasped the idea. But I've read in an article or two that data warehousing allows you to do analysis on data ...
0
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0answers
30 views
How to handle multiple changing ID's for a single person
I have a company with a single party table containing Member ID(the primary key), Subscriber ID, Member Sequence ID, Legacy ID, and a myriad of other identifiers from random source systems. Because ...
2
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2answers
1k views
Which DB for 1 table with 100 Million rows per year? [closed]
I've a questionnaire with 70 questions and need to store the answers.
Problem: it's 100 Million records per year.
I've experience with different types of storages, but never had to deal with these ...
7
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2answers
1k views
What is the best option for High availability on a data warehouse?
I have a customer who have an existing 1.5Tb data warehouse and are currently planning for a complete refresh of the DW on a new environment. Their infrastructure manager has organised 2 servers with ...
0
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0answers
42 views
Dimension attribute with one-to-many relationship
I have a request for an attribute in a dimension that has a one-to-many relationship with the lower level of the dimension.
Here is the case:
Dimension: Employee
Attribute: Immatriculation
I have ...
0
votes
1answer
67 views
Aggregating Multiple COTS Databases into a Data Warehouse or similar for Reporting
I am sure this is a very basic question, so I apologize, but I've read lots of articles and done a lot of google searches and have not found any leads for this particular challenge I am looking to ...
1
vote
1answer
50 views
How do you partition an events table by a time based off the datediff(Lag,time)?
I am not sure how really to ask this question as i have never come across such grouping/ partitioning before.
Basically i have an events table with 50 million rows that give me a timestamp, user, ...
0
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1answer
26 views
How to model changing OrderLine rows in fact table
In our business, we have Orders that are made up of OrderItems. Over time, these Orders can change status (e.g. Received, Challenged, Planned, Completed). During this process, the OrderItems for an ...
0
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1answer
127 views
Can a factless fact table be a bridge table?
As for bridge tables, they can be a helper table both for facts and dimensions. But can the factless fact table be a bridge table?
2
votes
1answer
78 views
Why student attendance is not considered a fact in data warehousing?
In a KimballGroup example student attendance is not considered a fact. Hence it considers this example as forming factless fact table. I don't really understand what is the difference between a fact ...
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0answers
21 views
How can I filter first then show values in BI?
As my title, I'm in this trouble. When I create a BI publisher report, it's show all of value, I just can filter after that.
Can someone tell me know how can I filter values before show it in BI ...
0
votes
1answer
376 views
Data Warehouse Modeling: Sales Order Charges [closed]
I have two databases systems that I'm trying to dimensional model a sales order business. Both operational data stores have a Sales Order header and detail table. However, one of them has an ...
0
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0answers
304 views
Dimensional Model for CRM Sales Opportunity and Sales Leads: Fact or Dimension?
I'm working for a business lender, and trying to come up with a basic dimensional model around the subject area of loan approvals.
We use a CRM, (Salesforce) and one of the core objects is a (Sales) ...
3
votes
1answer
533 views
Dimensional Modeling of a Loan Approval Process and Fact Grain(s)
Context:
I'm modeling for a lending company and I'm modeling our loan approval process. I have some basic dimensions relative to our business figured out:
Time(day)
Account
Opportunity
...
0
votes
1answer
44 views
Appropriate situation to data warehouse and how to best manage the warehouse? [closed]
I have a query that is on the opening page of our application that takes about 8-10 seconds to load. I've tried all I can to optimize it and I simply cannot make it go any faster (indexed ...
1
vote
1answer
337 views
Error on Datastage when I try to write on AS400
I'm having troubles to operate an ETL process on DataStage.
I have the following error log:
#TABLE#,0: ODBC function "SQLExecute" reported: SQLSTATE = HY000: Native Error Code = -332: Msg = [IBM(...
2
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0answers
41 views
How to implement updates from mySQL operational DB to Azure SQL DB for reporting
We have an operational mySQL DB running on AWS for a transactional system and an Azure SQL DB for reporting with PowerBI. Now I'd like to regularly (e.g. every night) do an update of certain tables ...
0
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0answers
54 views
does a fact table always need to have a field for aggregate?
When I was studying data warehouse modeling, the first thing I came into contact with was the order fact table, and the product, user, date dimension tables.
The order table will have quantity, ...
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0answers
622 views
Where to build the OLAP cubes? [closed]
I have built a data warehouse with multiple fact tables and dimension tables (with a MySQL server).
Now where could I build the OLAP cubes and write the MDX queries to produce results?
BTW, I have ...
2
votes
1answer
676 views
Run SQL Agent Job 3 times in a Row
How do I execute SQL Agent job 3 times in a row?
We are creating Data Warehouse Project. It ETLs data from Flatfile Legacy Folder, and creates Dim and Fact tables.
SSIS Project Environment Variable (...
