Ravi

• Jun 19th, 2005

 

they are of two types insert--> if it is not there in the dimension and update--> if it exists.

Prabhu B

• Jun 28th, 2005

 

Conventional Load: 
Before loading the data, all the Table constraints will be checked against the data. 
 
Direct load:(Faster Loading) 
All the Constraints will be disabled. Data will be loaded directly.Later the data will be checked against the table constraints and the bad data won't be indexed.

Vijaya

• Oct 4th, 2005

 

Conventional and Direct load method are applicable for only oracle. The naming convension is not general one applicable to other RDBMS like DB2 or SQL server..

manisha.sinha

 Profile Answers by manisha.sinha 

• Dec 29th, 2006

 

The answer to this depends on what kind of Dimension are we loading. If it is not changing , then simply insert.

If it is slowly changing dim of type 1 , update else insert(50% of the time)

Type 2, Only Insert (50% of the time)

Type 3 ,Rarely used as we create a new feild and and effective date.

DWH01

 Profile Answers by DWH01 

• Jul 1st, 2008

 

The data in the dimension tables may change over a period of time.  Depending upon how you want to treat the historical data in dimension tables, there are three different ways of loading the (slowly) varying dimensions:
1. Type One Dimension: do not keep the history.  Hence update the record if found, else insert the data.
2. Type Two Dimension: Do not update the existing record.  Create a new record (with version number or change date as part of key) of the dimension, while retaining the old one.
2. Type three Dimension keeps more than one column for each changnig attribute. The new value of the attribute is recorded in the existing record, but in an empty column. 
Type 2 dimensions are the most commonly used dimension.

spatnam

 Profile Answers by spatnam 

• Dec 9th, 2008

 

Different ways of Loading Dimensions are
1) SPT (Simple pass through) Truncate the data before load every time. No history

2) SCD (Slowly changing dimensions)  NEW records will be inserted an can be tracked by version, date time or flag (Maintains Histoy  and current). Supports updates too.


3) SGD (Slowly growing dimensions) New records will be inserted, updates are taken care by adding new column to the table (Maintains history to a level and current).

ibrarx

 Profile Answers by ibrarx 

• Mar 7th, 2009

 

Following are the loading strategies to load data in dimensional table.

1. Full data refresh.
Delete the existing data in the table and then update all the data with new
data.

2. Incremental data refresh (By handling the duplicates)
a. Constructive merge: If data exists before then load it with new primary key,
and add timestamp so that the new data can be identified easily.
b. Destructive merge: If data exists before then load the new data with the new
primary key and delete old record.

kevin0209

 Profile Answers by kevin0209 

• Aug 30th, 2010

 

Conventional Load: Before loading the data, all the Table constraints will be checked against the data.

Direct load: (Faster Loading) All the Constraints will be disabled. Data will be loaded directly. Later the data will be checked against the table constraints and the bad data won't be indexed.

mukul konch

• Aug 16th, 2014

 

The data in the dimension tables may change over a period of time. Depending upon how you want to treat the historical data in dimension tables, there are three different ways of loading the (slowly) varying dimensions:

1. Type One Dimension: do not keep the history. Hence update the record if found, else insert the data.

2. Type Two Dimension: Do not update the existing record. Create a new record (with version number or change date as part of key) of the dimension, while retaining the old one.2. Type three Dimension keeps more than one column for each changing attribute. The new value of the attribute is recorded in the existing record, but in an empty column. Type 2 dimensions are the most commonly used dimension.

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.

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
102,102_Address1
For existing surrogate/business key (it could be natural or compound keys
For example:
type1-
-------------
Case1: in Existing customers (can be identified by his unique Key: (to reflect new address in customer Diemension)
Update customer address, when moved to new address/ changed -> For keeping only current status (type -1)

case2:insert new customer record
on 06-26-2017
*****************************
101,101_address2
102,102address1

type2-
Case1: -For existing customers
insert brand new record with incrementing rowID -> building history. Say, if customer moved to different location in a year
we wanted to know where he was used live previousley.
case2: -insert new customer record
on 06-26-2017
*****************************
101,101_address1, 06-26-2016
101,101_address2, 06-26-2017
102,102address1, 06-26-2017