Basic diff is E-R modeling will have logical and physical model. Dimensional model will have only physical model. E-R modeling is used for normalizing the OLTP database design. Dimensional modeling is used for de-normalizing the ROLAP/MOLAP... Read More

surrogate key is a substitution for the natural primary key. It is just a unique identifier or number for each row that can be used for the primary key to the table. The only requirement for a surrogate primary key is that it is unique for each row... Read More

Hybrid SCDs are combination of both SCD 1 and SCD 2. It may happen that in a table, some columns are important and we need to track changes for them i.e capture the historical data for them whereas in some columns even if the data changes, we don... Read More

View - store the SQL statement in the database and let you use it as a table. Everytime you access the view, the SQL statement executes. Materialized view - stores the results of the SQL in table form in the database. SQL statement only executes... Read More

Every company has methodology of their own. But to name a few SDLC Methodology, AIM methodology are stardadly used. Other methodologies are AMM, World class methodology and many more. Read More

Question : 1.what is incremintal loading? 2.what is batch processing? 3.what is crass reference table? 4.what is aggregate fact table Answers: Incremental loading means loading the ongoing changes in the OLTP. Aggregate table... Read More

I think, there are two main things 1. Top down - (bill Inmon) 2.Bottom up - (Ralph kimbol) Read More

Junk dimension: Grouping of Random flags and text Attributes in a dimension and moving them to a separate sub dimension. Degenerate Dimension: Keeping the control information on Fact table ex: Consider a Dimension table with fields like order... Read More

Data type of the surrogate key is either integer or numeric or number Read More

RDBMS Schema * Used for OLTP systems * Traditional and old schema * Normalized * Difficult to understand and navigate * Cannot solve extract and complex problems * Poorly modelled DWH Schema * Used for OLAP systems * New generation schema ... Read More

Conformed dimensions are the dimensions which can be used across multiple Data Marts in combination with multiple facts tables accordingly Read More

Star schema A single fact table with N number of Dimension Snowflake schema Any dimensions with extended dimensions are know as snowflake schema Read More

As far I know... Gathering bussiness requiremnts Identifying Sources Identifying Facts Defining Dimensions Define Attribues Redefine Dimensions & Attributes Organise Attribute Hierarchy & Define Relationship Assign Unique Identifiers... Read More

Dimensional Modelling is a design concept used by many data warehouse desginers to build thier datawarehouse. In this design model all the data is stored in two types of tables - Facts table and Dimension table. Fact table contains the facts... Read More

Hierarchies Hierarchies are logical structures that use ordered levels as a means of organizing data. A hierarchy can be used to define data aggregation. For example, in a time dimension, a hierarchy might aggregate data from the month level to the... Read More

Basically the fact table consists of the Index keys of the dimension/ook up tables and the measures. so when ever we have the keys in a table .that itself implies that the table is in the normal form. Read More

Product information,sales information Read More

Both differed in the concept of building teh datawarehosue.. According to Kimball ... Kimball views data warehousing as a constituency of data marts. Data marts are focused on delivering business objectives for departments in the organization. And... Read More

Normalization is the process of removing redundancies. Denormalization is the process of allowing redundancies. Read More

Datatype of the surrgate key is either inteeger or numaric or number Read More

Data Mining is used for the estimation of future. For example, if we take a company/business organization, by using the concept of Data Mining, we can predict the future of business interms of Revenue (or) Employees (or) Cutomers (or) Orders etc. ... Read More

BUS Schema is composed of a master suite of confirmed dimension and standardized definition if facts. Read More

Types of data warehousing 1. Enterprise Data warehousing 2. ODS (Operational Data Store) 3. Data Mart Read More

Star schema contains the dimesion tables mapped around one or more fact tables. It is a denormalised model. No need to use complicated joins. Queries results fastly. Snowflake schema It is the normalised form of Star schema. contains indepth... Read More

Fact is key performance indicator to analyze the business.Dimension is used to analyze the fact.Without dimension there is no meaning for fact. Read More

Linked cube in which a sub-set of the data can be analysed into great detail. The linking ensures that the data in the cubes remain consistent. Read More

Yes.But those datatype will be char (only the values can numeric/char) Read More

Static variable is not created on function stack but is created in the initialized data segment and hence the variable can be shared across the multiple call of the same function. Usage of static variables within a function is not thread safe. On... Read More

if you are a Report developer 1,you have to specify the front end and back end tool used for creating the reports 2,Then you have to tell the purpose of the project..what you are going to acheive using the reports. 3,Then you can explain the... Read More

Cubes are logical representation of multidimensional data.The edge of the cube contains dimension members and the body of the cube contains data values. Read More

Data validation is to make sure that the loaded data is accurate and meets the business requriments. Strategies are different methods followed to meet the validation requriments Read More

Three different data types: Dimensions,Measure and Detail. View is nothing but an alias and it can be used to resolve the loops in the universe. Read More

Meta data is the data about data; Business Analyst or data modeler usually capture information about data - the source (where and how the data is originated), nature of data (char, varchar, nullable, existance, valid values etc) and behavior of data ... Read More

Degenerate Dimensions : If a table contains the values, which r neither dimesion nor measures is called degenerate dimensions.Ex : invoice id,empno Read More

A data mart is a focused subset of a data warehouse that deals with a single area(like different department) of data and is organized for quick analysis. Read More

Ralph Kimball Read More

Various ETL tools used in market are: Informatica Data Stage Oracle Warehouse Bulider Ab Initio Data Junction Read More

The perception of what constitutes a VLDB continues to grow. A one terabyte database would normally be considered to be a VLDB. Read More

The Entity-Relationship (ER) model was originally proposed by Peter in 1976 [Chen76] as a way to unify the network and relational database views. Simply stated the ER model is a conceptual data model that views the real world as entities and... Read More