Designing a Temporal Table for Time-Based Data Management

Designing a Temporal Table for Time-Based Data Tracking

Write a SQL query to design a temporal table for tracking time-based data changes.

Solution:

-- Temporal table for tracking employee data changes.
CREATE TABLE Employees (
    EmployeeID INT PRIMARY KEY,
    Name VARCHAR(100),
    Salary DECIMAL(10, 2),
    SysStartTime DATETIME2 GENERATED ALWAYS AS ROW START,
    SysEndTime DATETIME2 GENERATED ALWAYS AS ROW END,
    PERIOD FOR SYSTEM_TIME (SysStartTime, SysEndTime)
) WITH (SYSTEM_VERSIONING = ON (HISTORY_TABLE = dbo.EmployeeHistory));

Explanation:

• Purpose of the Query :
• The goal is to design a temporal table to track changes to data over time.
• Key Components :
• SysStartTime and SysEndTime: Track the validity period of each row.
• SYSTEM_VERSIONING: Automatically maintains a history table for tracking changes.
• Why use Temporal Tables? :
• Temporal tables provide built-in support for tracking historical data.
• They simplify compliance and auditing requirements.
• Real-World Application :
• In HR systems, temporal tables track changes to employee salaries or roles.

Notes:

• Temporal tables are supported in modern relational databases like SQL Server and PostgreSQL.
• Use them for scenarios requiring point-in-time analysis or auditing.
• Important Considerations:
• Regularly monitor storage usage for history tables.

For more Practice: Solve these Related Problems:

• Write a SQL query to design a temporal table for tracking changes to product inventory levels over time.
• Write a SQL query to create a temporal table for managing historical data of customer account balances.
• Write a SQL query to design a temporal table for tracking changes to employee work hours and schedules.
• Write a SQL query to create a temporal table for auditing modifications to supplier contracts and terms.

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Previous SQL Exercise: Designing a Polymorphic Association for Flexible Relationships.