time series database design

Question

I am a beginner in database design, researching ways in which to implement a time-series data. Basically, I want to design a database that store battery metrics i.e. current, voltage and the time for users. The more I think about it, the more I start to confuse myself. Please help me to point in the rieght direction. So far, I come up with the following psuedo-code:

   Table: User
    Column 1: UserID( Primary Key )
    Column 2: UserName

    Table: Battery 
    Column 1: BatteryID  ( Primary Key )
    Column 2: ManufactureSerial
    Column 3: ManufactureDate
    Column 4: UserID (Foreign Key )

    Table: BatteryLog
    Column 1: Voltage 
    Column 2: Current 
    Column 3: SOC 
    Column 4: DateTime 
    Column 5: BatteryID (Foreign Key)

Now, my question is: what should be the primary key for BatteryLog table? A batterylog can contain millions of Time-Series rows at a specified time internal. I am using SqlServer relational database now. Is there a optimization design for it?

Thank you for your help in my research!

Answer 1

You can create an autoincremental primary key for BatteryLog table:

[BatteryLogID] [int] IDENTITY(1,1) NOT NULL

This will serve the purpose of unique identifier for each record.

Alternatively, you can create a composite primary key on BatteryID and [DateTime] if they are also unique for each record (which is usually the case for time series)