data-warehouse

Time and date dimension in data warehouse

I'm buildind an data warehouse. Each fact has it's timestamp. I need to create reports by day, month, quater but by hours too. Loking at the examples I see that dates tend to be saved in dimension tabels. But I think, that it makes no sense for time. The dimension table would grow and grow. On the other hand JOIN with date dimension ta...

PostgreSQL to Data-Warehouse: Best approach for near-real-time ETL / extraction of data

Background: I have a PostgreSQL (v8.3) database that is heavily optimized for OLTP. I need to extract data from it on a semi real-time basis (some-one is bound to ask what semi real-time means and the answer is as frequently as I reasonably can but I will be pragmatic, as a benchmark lets say we are hoping for every 15min) and feed it...

ETL Operation - Return Primary Key

I am using Talend to populate a data warehouse. My job is writing customer data to a dimension table and transaction data to the fact table. The surrogate key (p_key) on the fact table is auto-incrementing. When I insert a new customer, I need my fact table to reflect the id of the related customer. As I mentioned my p_key is auto auto...

Using MS SQL Server Analysis Services to create cubes on hierarchical data

I have a hierarchy, like an ProductDimension hierarchy. Currently, I query this table using the Nested Sets methodology. I write the usual star-schema joins to get a time-series report of groups of Products (Batches, CountryOfOrigin, ProductLine, etc.). I'm currently investigating using SSAS cubes- but can a cube model this? Are ther...

Metadata requirements for developers

I'm tasked with providing a list of metadata requirements our data warehouse developers might need. This is not the business metadata (nice descriptions etc), but rather data required for change management (also known as impact assesment), data lineage etc. I've seen this article Meta Meta Data Data - Ralph Kimball but as I'm not the f...

Should we put our Reporting data warehouse on our Transaction database Server.

We are about to add a Reporting Data Warehouse to our system. Currently we are using Oracle 10g for our transaction database. Should we put the Reporting Warehouse on physically different hardware? or can we "go cheap" and share the Transaction Server? ...

Loop Control within a DataflowTask in ETL

Hi, Being fairly new to SSIS and the ETL process, I was wondering if there is anyway to loop though a record set within a DataFlowTask and pass each row (deriving parameters from the row) into a Stored Procedure (the next step in the ETL phase). Once i have passed the row into the stored procedure, I want the results from each iteratio...

Delta Extraction + Business Intelligence

What does Delta Extraction mean in regards to Data Warehousing. ...

select all values from a dimension for which there are facts in all other dimensions

I've tried to simplify for the purposes of asking this question. Hopefully, this will be comprehensible. Basically, I have a fact table with a time dimension, another dimension, and a hierarchical dimension. For the purposes of the question, let's assume the hierarchical dimension is zip code and state. The other dimension is just des...

3rd party data - Store in Data Warehouse or Primary database?

This is mostly a data warehouse philosophy question. My project involves an Oracle forms application, and a Teradata Data Warehouse for reporting and ad-hoc purposes. In addition to the primary data created by the users of our application, we also require data from various other sources. Currently, this 3rd party data comes via FTPd fla...

Analysis Services Partitioning Issue

I have a Measure Group, that is partitioned daily. I can process a particular partition, and the XMLA command completes successfully. Furthermore, I have ensure at least one partition is processed for every Measure Group, therefore my cube is "partially processed" and I should be able to browse it. The problem... no data can be seen i...

NoSql and Data-Warehouse

What are the relations between NoSql and Data-Warehouse technologies/theories? What concepts they share? What are the basic differences between them? How do you think each could be benefits/enriches from the other? I think your ideas should be helpful for the future of both technologies. ...

Is it good practice to have foreign keys in a datawarehouse (relationships)?

I think the question is clear enough. Some of the columns in my datawarehouse table could have a relationship to a primary key. But is it good practice? It is denormalized, so it should never be deleted again (data in datawarehouse). Hope question is somewhat clear enough. ...

Data warehousing in sql server 2008

Hi All: I am new to data warehousing and I am a little confused plz provide some simple steps to create a cube and fill it and make querey on it to know : I have a database with the original data and I have designed the star schema and made appropriate tables I have created an analysis service project in VS 2008 and then I have made the ...

What is the best FREE solution to implement one ETL project in MySql

Hi, What is the best FREE solution to implement one ETL project in MySql? I need to extract for analisys big amount of data, and put the results in other tables. Regards, Pedro ...

Handling primary key duplicates in a data warehouse load

I'm currently building an ETL system to load a data warehouse from a transactional system. The grain of my fact table is the transaction level. In order to ensure I don't load duplicate rows I've put a primary key on the fact table, which is the transaction ID. I've encountered a problem with transactions being reversed - In the transac...

open source business intelligence solutions

which open source business intelligence solution would you recommend? All I need is to build some cubes and let the end user play with dimensions, filter data, sort, etc, and once it's done being able to export it to excel... I'd like the solution to be as simple and easy on resources as possible, and also I'd like it to be as much ope...

Database design: one huge table or separate tables?

Currently I am designing a database for use in our company. We are using SQL Server 2008. The database will hold data gathered from several customers. The goal of the database is to acquire aggregate benchmark numbers over several customers. Recently, I have become worried with the fact that one table in particular will be getting very ...

Need some information regarding data warehousing field

I am a web developer and i would like to shift my field to data warehousing. Can anyone please give me some idea , which langauges or stuff i need to learn like cogonos , datastage, etl or IF anyone currently working can guide me how can i start , i will thankful to you. DO i nned to do oracle because i know mysql , sql. My basic under...

Can oracle 10g can be the used for multi dimensional data warehouse ?

I am new to the data warehousing and was just curious to know if oracle 10g or MySql can be used for multi dimensional data warehouse or we can only use something like Hyperion ? ...