Logging SQL Errors for Debugging and Analysis

Logging Errors to a Table

Write a SQL query to log errors to a dedicated error log table.

Solution:

-- Create an error log table.
CREATE TABLE ErrorLog (
    LogID INT IDENTITY(1,1) PRIMARY KEY,
    ErrorMessage NVARCHAR(MAX),
    ErrorTime DATETIME DEFAULT GETDATE()
);

BEGIN TRY
    -- Simulate an error.
    SELECT 1 / 0 AS Result;
END TRY
BEGIN CATCH
    -- Log the error to the ErrorLog table.
    INSERT INTO ErrorLog (ErrorMessage)
    VALUES ('Error: ' + ERROR_MESSAGE());
END CATCH;

Explanation:

• Purpose of the Query :
• The goal is to log errors to a table for later analysis and debugging.
• Key Components :
• ErrorLog: A dedicated table for storing error details.
• INSERT INTO ErrorLog: Logs the error message and timestamp.
• Why Log Errors? :
• Logging errors provides a record of issues for troubleshooting and auditing.
• It helps identify recurring problems and improve system reliability.
• Real-World Application :
• In production systems, error logs are critical for monitoring application health.

Additional Notes:

• Include additional details like error severity, procedure name, or user context in the log.
• Regularly review and archive error logs to manage storage.
• Important Considerations:
• Ensure that the error log table is secure and accessible only to authorized users.

For more Practice: Solve these Related Problems:

• Write a SQL query to log errors along with the stored procedure name and line number where the error occurred.
• Write a SQL query to create a trigger that logs constraint violations into an error log table.
• Write a SQL query to archive old error logs older than 30 days into a separate table for historical analysis.
• Write a SQL query to generate a report of the top 10 most frequent errors from the error log table.

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