简单的看下架构，
分成几个部分，
Connection And Session
The Connection and Session Management component creates and manages sessions and connections for the database clients.
Interface
Database clients can use SQL (via JDBC or ODBC), SQL Script, MDX or other domainspecific languages like SAP’s proprietary language FOX
for planning applications, or WIPE, which combines graph traversal and manipulation with BI-like data aggregation to communicate with the HANA database.
Transaction Manager
Calculate Engine
MetaData
Optimizor And Executor
In-Memory Storage Engine
Hana在内存里面同时支持3种内存存储引擎，关系型，Graph，Text
感觉这块是Hana主要的特点，来个大杂烩，你要啥，给你啥
Hana的性能优势也主要因为这些数据是放在内存中的
Persistence Layer
防止数据不丢
Beyond SQL
Hana还有个特点是，商业数据库
