Data warehouse （data  warehouse ,DW）

Definition

Data warehouse is a subject oriented integrated nonvolatile and time-varying data set .

It is mainly used to organize the accumulated historical data , And use analytical methods （OLAP, Data analysis ） Analyze and organize , And then assist in decision-making , For managers , Enterprises provide data support , Building business intelligence .

characteristic

1 subject-oriented ： Gather the raw data according to the topic .

2 Integrate The original data source does not , Need to go through ETL conversion （ cleaning , Uniform standard ）

3 Nonvolatile ： Not allowed to be modified , Only query 、 analysis  

4 Time varying ： Several positions Will accept regularly . Integrate new data , So as to reflect the latest changes in data .

Several positions  vs database

Database object-oriented design , Belong to OLTP System , The main operation is random reading and writing , Avoid redundancy in design , It is often designed with compound paradigm specification ;

Data warehouse is designed for theme , Belong to OLAP, The main operations are batch reading and writing , Focus on data integration , And analyze the processing performance , Will deliberately introduce redundancy , Design in an anti paradigm way ;