What is the difference between Full load and Incremental load

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#OBIA #ETL #Full Load #Incremental Load

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本文详细解释了OBIA项目中全量加载和增量加载的概念，包括它们的区别、特点以及应用场景。全量加载是在首次加载时进行整个数据集的导入，而增量加载则是在特定时间间隔内只加载自上次加载以来新增的数据记录，以提高效率并保留历史数据。

In most OBIA projects we create both incremental and full load mappings for each tables in Date Warehouse target. Below you can find the difference between both.

Full Load is the entire data dump load taking place the very first time. In this we give the last extract date as empty so that all the data gets loaded

Incremental - Where difference between target and source data is dumped at regular intervals.Here we give the last extract date such that only records after this date are loaded.

Note:

Full load: $$Last_Extract_Date = either leave it blank or give some old date so that all the records are loaded

Incremental load:$$Last_Extract_Date = The date from which you need the data (to get latest record).

- See more at: http://dwhlaureate.blogspot.jp/2012/06/what-is-full-load-incremental-load-full.html#sthash.Sn5gFBNo.dpuf

Note:

Full load: $$Last_Extract_Date = either leave it blank or give some old date so that all the records are loaded

Incremental load:$$Last_Extract_Date = The date from which you need the data (to get latest record).

- See more at: http://dwhlaureate.blogspot.jp/2012/06/what-is-full-load-incremental-load-full.html#sthash.Sn5gFBNo.dpuf

Note:

Full load: $$Last_Extract_Date = either leave it blank or give some old date so that all the records are loaded

Incremental load:$$Last_Extract_Date = The date from which you need the data (to get latest record).

- See more at: http://dwhlaureate.blogspot.jp/2012/06/what-is-full-load-incremental-load-full.html#sthash.Sn5gFBNo.dpuf

Note:
Full Load: Last_Extract_Date = either leave it blank or give some old date so that all the records are loaded.
Incremental Load: Last_Extract_Date = The date from which you need the data (to get latest record).

Why Incremental:

Speed.

Preserving history.

Full Load vs Incremental Load:

Full Load	Incremental Load
Truncates all rows and loads from scratch.	New records and updated ones are loaded
Requires more time.	Requires less time.
Can easily be guaranteed	Difficult. ETL must check for new/updated rows.
Can be lost.	Retained.