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iotdb 数据模型和术语     所属分类 iotdb 浏览量 32
http://iotdb.apache.org/UserGuide/V0.10.x/Concept/Data%20Model%20and%20Terminology.html

Data Model and Terminology

set storage group to root.ln
create timeseries root.ln.wf01.wt01.status with datatype=BOOLEAN,encoding=PLAIN
insert into root.ln.wf01.wt01(timestamp,status) values(1509465600000,true)
insert into root.ln.wf01.wt01(timestamp,status) values(1509465660000,true)
insert into root.ln.wf01.wt01(timestamp,status) values(1509465720000,false)
insert into root.ln.wf01.wt01(timestamp,status) values(1509465780000,false)
insert into root.ln.wf01.wt01(timestamp,status) values(1509465840000,false)


attribute hierarchy structure
属性层次结构

power group layer 
power plant layer 
device layer 
sensor layer

ROOT is the root node, and each node of sensor layer is called a leaf node

ROOT.ln.wf01.wt01.status

avoid frequent switching of IO when writing data
physical isolation of data in the unit of groups
set the storage group at the group layer

group layer  , storage group
避免IO写入切换  ,数据物理隔离

Device
Sensor
storage group
organize and isolate different time series data on disk. 

Time series belonging to the same storage group will be continuously written to the same file in the corresponding folder. 

合理设置存储组个数
根据数据量大小和实际场景

Once a prefix path is set as a storage group, the storage group settings cannot be changed.

After a storage group is set, all parent and child layers of the corresponding prefix path are not allowed to be set up again 
for example, after root.ln is set as the storage group, the root layer and root.ln.wf01 are not allowed to be set as storage groups.


Path

Timeseries Path
root.vehicle.device1.sensor1

Prefix Path

Path With Star

Note1: * cannot be placed at the beginning of the path.
Note2: A path with * at the end has the same meaning as a prefix path, e.g., root.vehicle.* and root.vehicle is the same.



Timestamp

Absolute timestamp

Relative timestamp

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