Data Warehousing Basics

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    Fact Table

    Fact Table is
    a) Completely Normalized
    b) Partially Normalized
    c) Completely De-normalized
    d) Partially De-normalized

    Vidhan

    • Feb 23rd, 2018

    A.) Completely Normalized

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    1.what is incremental loading?2.what is batch processing?3.what is cross reference table?4.what is aggregate fact table

    kamesh

    • Jan 30th, 2018

    Incremental loading is defined as the activity for only loading new records and updated records from a database into an established in a Quick view detect Batch processing is the process of series of ...

    Andrey Parkhomets

    • Feb 27th, 2012

    cross reference table used to describe many-2-many relation between tables. aggregate fact table - when granularity of fact data not required fact can be grouped over dimensions, measures will be af...

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    Explain degenerated dimension in detail.

    kamesh

    • Jan 30th, 2018

    A Dimension which is derived from the fact table and doesnt have its own dimension table A degenerate dimension is a transaction based number. A degenerated dimensions are often called as textual fact...

    TimeBeing

    • Jan 25th, 2017

    A Dimension table which have the values of Fact table is called "De-Generated Dimension".

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    How can I verify the latest data from above table?

    I have a table with two columns name namely current,history but I dont have time stamp to make sure that when the data is updated or deleted.

    Now How can I verify the latest data from above table?

    kamesh

    • Jan 30th, 2018

    Based on the surrogate key we have identified the data Because surrogate keys is unique identifer for each row in a table

    fazal

    • Oct 29th, 2013

    Select max (ora_scan) from table;

    Select scn_to_timestamp (the_above_output) from dual;

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    What is the difference between star schema and snow flake schema? When we use those schema's?

    kamesh

    • Jan 30th, 2018

    A join is linked with only only one dim and one fact is called star schema
    A join is linked with more than one dimension is called Snow flake schema.

    sunny

    • Jul 5th, 2013

    star schema: When dimension table contains less number of rows, we can go for Star schema.In this Both Dimension and Fact Tables are in De-Normalized form.Good for datamarts with simple relationships ...

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    Why fact table is in normal form?

    kamesh

    • Jan 30th, 2018

    Basically Fact table contain Index keys of the dimension/lookups tables of the measures so when ever we have the keys in the table it implies itself the fact table is in Normal For.

    j123

    • Jun 9th, 2013

    Foreign keys of facts tables are primary keys of Dimension tables. It is clear that fact table contains columns which are primary key to other table that itself make normal form table.

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    What is Difference between E-R Modeling and Dimentional Modeling.

    Kamesh

    • Jan 30th, 2018

    ER represent the logical design technique that seeks to eliminated the data redundancy It shows the relationship between the data.
    DM is a logical technique that seek to present the data in standard intuitive to allow high performance access.

    Sreedhar Lokaray

    • Nov 3rd, 2011

    I think the answer the best suits this question is as below: Entity - Relationship Modelling:- Removes data redundancy. Ensures data consistency. Expresses relationship between the entities....

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    What is a Star Schema

    Answer posted by Chintan on 2005-05-22 18:34:55: A relational database schema organized around a central table (fact table) joined to a few smaller tables (dimension tables) using foreign key references. The fact table contains raw numeric items that represent relevant business facts (price, discount values, number of units sold, dollar value, etc.)

    kamesh

    • Jan 30th, 2018

    A join is linked with only one dimension and one fact is called Star chema

    TimeBeing

    • Jan 25th, 2017

    A Fact table is surrounded by multiple Dimension tables and which is look like STAR in graphical design is called "STAR Schema".

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    What is the difference between Datawarehouse and Datawarehousing

    Naveed Akhtar

    • Nov 4th, 2017

    "Data Ware House" is a complete repository of historical corporate data extracted from transaction system that is available for ad-hoc access by knowledge workers, (Complete Repository) Means All dat...

    Dr BK Verma

    • Jul 2nd, 2017

    Data Warehouse: It is just container to store the data from different sources. In this part we can't have right to analysis the data its just storage data. Data warehousing: If we use any intelligent...

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    What is surrogate key ? Where we use it explain with examples?

    Star Read Best Answer

    Editorial / Best Answer

    Answered by: saravanan

    • Dec 2nd, 2005


    Surrogate key is a unique identification key, it is like an artificial or alternative key to production key, bz the production key may be alphanumeric or composite key but the surrogate key is always single numeric key. Assume the production key is an alphanumeric field if you create an index for this fields it will occupy more space, so it is not advisable to join/index, bz generally all the datawarehousing fact table are having historical data. These factable are linked with so many dimension table. if it's a numerical fields the performance is high

    P.Manideep

    • Oct 29th, 2017

    Surrogate key is system generated key. It is a column or set of columns declared as primary key instead of real of natural key.

    Anukul Thawarey

    • Aug 8th, 2017

    Just to add on to this point, we can also have date stamp as in the format (yyyymmdd) which is actually an 4 Byte unsigned integer to keep track of the historical data. This date stamp column can also be considered as an surrogate key.

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    What are the Different methods of loading Dimension tables

    praveen

    • Jun 26th, 2017

    how do you update when customer changed address: on 06-26-2016 -------------- 101,101_address1, on 06-26-2017, customer 101 moved to new loc and 102 added ---------------- 101,101_Address2 ...

    TimeBeing

    • Jan 25th, 2017

    There are 2 types of data loading.
    1. Initial Loading: Data loading for the first time in to Table/Database is called Initial Loading.

    2. Incremental Loading: Inserting new data and updating existing data which comes with new values is Incremental Loading.

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    Can a dimension table contains numeric values?

    Kamlesh

    • Jun 22nd, 2017

    Yes dimension table can contain numeric value. i.e. Product dimension can have price, quantity as numeric values

    uday

    • Aug 17th, 2016

    Yes, A dimension Table can have numeric data types and information. For example. the surrogate key columns which are numeric. and in a scenario if a product has min discount and max discount column...

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    Max of Date using Aggregation

    How to find Max and Min of date in aggregation ?


    Input:
    Empid start_date End_date Sal
    1 2015-01-01 2015-12-31 1000
    1 2016-01-01 2017-05-29 2000
    2 2014-01-01 2015-12-31 1000
    2 2016-01-01 2017-03-15 800
    3 2011-01-01 2015-12-31 1000
    3 2016-01-01 2017-05-10 1200
    4 2016-01-01 2017-02-14 2000


    Output_Should be like...

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    What is data cleaning? how is it done?

    vijay

    • May 25th, 2017

    While loading the data from Source to Target, if we are removing unwanted data or converting inconsistent data to consistent format is data clensing

    TimeBeing

    • Jan 25th, 2017

    Data Cleansing is the process of converting inconsistent data into consistent data and removing unwanted data.

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    What is a Data Warehousing?

    Data Warehouse is a repository of integrated information, available for queries and analysis. Data and information are extracted from heterogeneous sources as they are generated....This makes it much easier and more efficient to run queries over data that originally came from different sources. Typical relational databases are designed for on-line transactional processing (OLTP) and do not meet the...

    chandrasekhar

    • Mar 10th, 2017

    The complete process of ETL activities (Extract, Transform and Load) and BI (Business Intelligence for generating reports) are called Data Warehousing.

    TimeBeing

    • Jan 25th, 2017

    Datawarehousing is a process of Designing a database Schema, ETL process and Reporting.

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    What is a lookup table

    TimeBeing

    • Jan 25th, 2017

    Lookup for some related data in Database or Flatfiles or Database View based on key column

    Johnson Weltch

    • Dec 16th, 2016

    This was great to know more about lookup table in database. You may also go through this informative article on look up table to get brief knowledge about Lookup table in database:
    Lookup table in SQL Server at sqlmvp org

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    What is the Difference between OLTP and OLAP

    Answered by swetha on 2005-03-30 12:00:33: OLTP  Current data Short database transactions Online update/insert/delete Normalization is promoted High volume transactions Transaction recovery is necessary   OLAP Current and historical data Long database transactions Batch update/insert/delete Denormalization is promoted Low...

    ram

    • Aug 30th, 2016

    OLTP: Original Source of data
    Running on fundamental business task

    OLAP: Data coming from various OLTP sources
    Problem Solving, Decision Making

    Pravin

    • Jan 16th, 2015

    Very useful answer.
    thanks.

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