A database system optimised for reporting, particularly in aggregate. Often, but not always implemented using a star schema.

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1answer
152 views

Advices for modeling facts, time hierarchies based on two conditions

Sorry if my question does not belong to that SE but I tried to find the best place and it ended up here. My problem is this : I've got a table modeled as this in our datawarehouse env. : MYTABLE ...
5
votes
1answer
374 views

When should startup parameter -E be used?

We are starting to build a data warehouse system using SQL Server 2008 R2. One of the senior DBAs told us to consider using a startup parameter -E for the SQL Server service. I read from Books Online ...
4
votes
2answers
582 views

Isolation Level for a Data Warehouse

We are building out a data warehouse (and also some data marts as well) in our organization. My DBA skills have mostly been on OLTP type applications, but I am moving into supporting OLAP for our ...
2
votes
1answer
1k views

In star schemas, what should I do when a dimension has a date attribute?

I'm trying to learn about dimensional models and star schemas. Say I have a Sales fact table recording the total sales at retail stores, with, say, four dimensions, Date, Customers, Stores, and ...
0
votes
1answer
44 views

Oracle scheduler chain priority in data warehouse applications

The scenario is as follows: We have a data warehouse type application that relies on the Oracle job scheduler and a Chain. This chain is responsible for generating materialized views (caches) that ...
0
votes
2answers
334 views

SQL Server 2005 replication for a data warehouse

We are trying to implement some kind of Data Warehouse at my current employer. Most of our data is in a SQL Server 2005, but we might also integrate some Access databases and some databases in a SQL ...
3
votes
1answer
437 views

How to represent aggregates in a data warehouse

I am building the dimensional model for a data warehouse (as an exercise for a mini-course I am doing) and I want to build an aggregate to speed up queries. Basically, I want the aggregate to group ...
4
votes
1answer
408 views

Should I Link a Fact to Hierarchical Dimension at ALL Levels or only the most granular?

Related question about the same project here. I'm looking at two approaches to model a hierarchical relationship between my fact and dimension tables in a data warehouse for storing IT infrastructure ...
8
votes
1answer
193 views

Dimension and Fact for same entities?

I'm rather new at DW design and am working on a DW to model some IT infrastructure. The major problem/question at this point is how to model drive information. We will be collecting aggregate data ...
2
votes
1answer
993 views

Does surrogate key assignment for a fact table require that the source data has natural keys?

Let's say I have a simple OLTP database with orders, products, and customers: And from it, I am building a data mart with an orders fact table, product dimension, customer dimension, and date ...
0
votes
1answer
226 views

How to simplify schema for multi database / hundreds of millions of rows data set

We currently have a MySQL data set that was started about 10 years ago that aggregates a log of data, and accumulates millions of rows each month. The people that developed our system started ...
3
votes
3answers
1k views

How do you roll up header-level values on a fact table with line-item granularity?

From what I've read, the recommended granularity for a fact table based on an order header / line item structure is at the line item level. In the process, any additive values that apply only to the ...
3
votes
1answer
110 views

Architectural Question about Data analytics

I understand that in many OLTP architectures there is some ELT stuff which creates a OLAP Data warehouse model and then you can run data analytics on this. However, this can take some time to ...
3
votes
1answer
148 views

Reporting Table Design

I'm writing a system that allows users to store values against each week in October and November and each day in December - starting from the first Monday. I'm holding the raw data entered by the ...
1
vote
2answers
556 views

SQL Server 2012 Data Warehousing Overall Flow [closed]

I am studying Data Warehousing in SQL Server 2012 I am attempting to learn the various tools included by practicing on the different tools separately. I have practiced with: AdventureWorks ...
8
votes
3answers
5k views

When should indexes be dropped and recreated?

We are constructing a data warehouse that initially will be 1 TB and will grow around 20gigs every month. For certain tables we are doing daily ETL processes and others we are doing weekly/monthly. ...
5
votes
1answer
318 views

Database structure, relational or data warehouse?

Good morning, Im having some issues with how my database should be laid out and would appreciate some guidance. I have several tables (rainfall data), each containing the following columns: Date ...
15
votes
3answers
7k views

What are the arguments in favor of using ELT process over ETL?

I realized that my company uses an ELT (extract-load-transform) process instead of using an ETL (extract-transform-load) process. What are the differences in the two approaches and in which situations ...
4
votes
1answer
494 views

Methodology & Architecture to Create ETL Process

What book or webpage can I read the architecture and methodology for creating ETL process? In other words, I'm looking for "how to do it" to create a ETL process when you have many source system to ...
2
votes
3answers
1k views

ETL: extraction strategy for 200 source databases

What is the best extraction strategy for approximately 200 SQL Server 2005 source databases (same schema) for a daily load into a staging area in preparation for data warehouse cleansing, ...
6
votes
2answers
367 views

What is the name of this schema pattern

Its been a few years... but I've run into a problem-set that reminds me of a schema design pattern and I'm trying to recall the details. Essentially, the pattern consists of one database which is 3 ...
3
votes
1answer
282 views

Proper Design for Datamart Invoice

I'm trying to design a set of fact tables for a datamart that will work in an ssas cube for one of our clients. One of the challenges I'm facing is that there appears to be some disperencies between ...
-7
votes
3answers
235 views

Business Intelligence = Technical OR Business Project? [closed]

Do you consider a project of Business Intelligence to be a technical or business project?
3
votes
2answers
2k views

ALTER TABLE SWITCH statement failed

ALTER TABLE SWITCH statement failed because column does not have the same ANSI trimming semantics in tables... Does anyone knows how to fix that on already existing table full of data? Well, I've ...
9
votes
2answers
2k views

100 TeraBytes Capacity Database - Resources and Time Estimates

I am working on a 'back of the envelope' calculation for a 100TB reporting database setup. I am seeking out thoughts from the experts here. Proposed environment: Storage Capacity ~ 100TB Tables ~ ...
2
votes
1answer
288 views

Review Technical ETL process for knowledge management

I'm looking for source code and all related component/material to review technical ETL process between source database and Data Warehouse in order to increase my knowledge in technical Business ...
0
votes
1answer
217 views

Using N-Tier in Business Intelligence

I have read that you also can apply N-Tier for Businesss Intelligence based on these criteria: *Presentation *Functional logic *Data What is your experience when you are using N-Tier? // ...
3
votes
2answers
3k views

Reindexing a large database

I have a very large database (millions of rows) which has been indexed. I receive a diff of rows from another source that I need to update in my database. The problem I am facing is that is it ...
1
vote
0answers
35 views

Monoblock, Multiblock queries?

What exactly mean the terms monoblock / multiblock queries in data warehouses when talking about materialized views? Does a monoblock query just use one data source (a normal table) while a multiblock ...
5
votes
3answers
262 views

How do I add a time dimension to this forecasting database without having to duplicate every data point @ each reforecast?

I have a database designed to facilitate revenue forecasting. Revenue forecasting consists of tracking Orders which are recognized into Revenue at multiple points in time (each, a revenueDate). There ...
2
votes
2answers
338 views

Data warehouse: using day number in Epoch in a date dimension

In Chapter 2 Retail Sales of Ralph Kimball's The Data Warehouse Toolkit, the author describes a date dimension with three fields which appear totally alien to me: Date Key (PK) Date Full Date ...
8
votes
2answers
6k views

PostgreSQL for high volume transactions and for Data warehousing

Am quite new to PostgreSQL, I have never done a large deployment using it before. But, I have good experience in enterprise solutions and I want to try and apply some of what I learned using ...
8
votes
2answers
6k views

Sql Server 2012 data warehousing and different versions

With Sql Server 2012 there are 3 flagship editions: Enterprise Edition, Business Intelligence, Standard. The full comparison between the three: ...
2
votes
1answer
192 views

Is dimensional modelling useful for modelling tables of calculations?

I have a set of tables that look a bit like this: Key 1 | Key 2 | Key 3 | Var 1 | Var 2 | Var 3 | ... | Var 200 ------------------------------------------------------------- X | Y | Z | ...
1
vote
1answer
2k views

How to move data from Primary Data File to other data file without destroying replication

I have one Database which is replicated using transactional replication. Now, I want do spare some data of that database to another partition, because my server running out of disk space. I was ...
1
vote
2answers
183 views

Designing an Accumulating Snapshot with Repeated Groups, need advise

Situation I need to create a pie chart that has to be able to be represented at the following levels: District, Region, and School. At the student level it has to show the trend of the student over ...
9
votes
1answer
7k views

Limit the degree of parallelism (DOP) available to any query

On Oracle Exadata (11gR2), we have a relatively beefy database. cpu_count is 24 parallel_server_instances is 2 parallel_threads_per_cpu is 2 We noted, through observation in Oracle Enterprise ...
4
votes
3answers
1k views

How can I make my SSIS process consume more resources and run faster?

I have a daily ETL process in SSIS that builds my warehouse so we can provide day-over-day reports. I have two servers - one for SSIS and the other for the SQL Server Database. The SSIS server ...
4
votes
3answers
3k 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, ...
8
votes
3answers
846 views

What advantages does in-memory OLAP have over traditional systems with significant memory?

Do in-memory OLAP engines have advantages over the traditional OLAP engines backed by enough RAM to contain the entire cube(s)? For example, if I use a MOLAP engine (SSAS) and GB / TB of RAM where ...
2
votes
1answer
361 views

Oracle Change Data Capture: Unsubscribed column results in change set record

I am using Oracle 11g's Change Data Capture to track changes on a database table. I am using synchronous mode to minimize latency. Here's an example to illustrate my problem: Published_Table ...
3
votes
2answers
4k views

What is SQL Server Parallel Data Warehouse?

What is SQL Server Parallel Data Warehouse solution? What is the benefit of PDW compared to normal DW architecture based on SQL Server and SSIS, SSAS and SSRS?
5
votes
1answer
413 views

Fact table design - Level or contribution measures

I am trying to come up with a dimensional model for the following: The source data comes from game machines as meter messages. Basically, the game machine accepts payments and sends a snapshot of the ...
2
votes
2answers
181 views

How to compare the database of a backup from another environment

Has anyone had any luck with taking a backup (approx 30 tables) from an Oracle database's live environment, then loading a test environment with this backup and doing a comparison between the test ...
3
votes
2answers
183 views

What are the best Database Analytics Companies for analyzing several 1000s or Mio. of products,sum them together and analyze them for statistics?

We will get several thousands products in our database. The problem is that one product can have several different names e.g. "iPad 16GByte UMTS schwarz" or "iPad 16GB 3G black" and so on. But they ...
2
votes
2answers
316 views

Indexing of Data Warehouse tables?

Maybe I have misunderstood something but I can recall reading an article which said that there is no reason to create non-clustered indexes on very large data warehousing tables? That is because ...
5
votes
1answer
288 views

DBA's Scope in datawarehousing Projects

As a DBA trainee, what needs to be known in order to be part of datawarehousing projects? I mean what resources are suggested to have an overview knowledge of how PL/SQL and other concepts are used ...
0
votes
2answers
2k views

Possible career paths for Oracle Certified Associate (OCA) [closed]

In order to be confident in databases as a entry level job candidate, I completed the OCA certification. Now I want to know what career paths follow this. Can one go into data-mining, BI, or ...
7
votes
2answers
2k views

Fact table foreign keys null?

I am new to data mart design and need to clear a few concepts. I have read up a bit on dimension modelling where I see that fact tables store foreign key references to dimension tables. Now suppose ...
7
votes
3answers
1k views

Suggestion for Large SQL Server Database Design

We are creating a database in MSSQL 2008 R2 Standard where we will be storing a large number of records. We estimate 200 million+ records in one table annually and we are primarily INSERTing with very ...