本章考点多为概念：

Data Orchestration(数据编排)
传统的数仓都是ETL
现代的数据湖一般是ELT

DII

数据集成（Data integration）: Consolidates data into  consistent forms(physical or virtual). Two or more systems can share data.

数据互操作能力（Data Interoperability）Provides ability for multiple systems to communicate: two or more systems remain unchanged and can work together.

DII 的业务驱动力:
1, when managing data movement efficiently is primary
2,Need to simplify sharing transcational and operational data across the organization
3,Integration of various data stores and accommodating external applications
 

Data types:

数据虚拟化：把很多的物理数据库，虚拟的存储在一起。

ETL：不一定只做数据仓库。
E(Extract): selecting, extracting,staging(physically or in memory)
T(Transform): Makes data compatible; remove ,copied trigger events. Examples: Format, structure, semantic conversion, de-duping, re-ordering
L(Load): Physically storing or presenting results in the target system in final or near-final form. 

ELT: Common in big data where ELT load the data lake.
Transformations occur after load.
Allows source data to be in raw form in the  target datastore.
 

12essential concepts: