Scribbles for my bad memory

We use Graylog to log everything, on Windows machines we also log into EventLog. I recently noticed for every exception in C# I got two items in EventViewer, one is Logged by our code, and the other is logged by the .net runtime I guess. It is a little bit annoying. TLDR; here's the answer:

        public override void OnException(ExceptionContext actionExecutedContext)
        {
            _logger.Error(actionExecutedContext.Exception);
+           actionExecutedContext.ExceptionHandled = true;
            actionExecutedContext.HttpContext.Response.StatusCode = StatusCodes.Status500InternalServerError;
            actionExecutedContext.Result = new ObjectResult(new ErrorResponse()
            {
                StatusCode = (HttpStatusCode) StatusCodes.Status500InternalServerError,
                Message = actionExecutedContext.Exception.Message,
            });
            base.OnException(actionExecutedContext);
        }

The key is this line actionExecutedContext.ExceptionHandled = true;. Reference

Occasionally, we will need to define local used functions in a public procedure or a function. Fortunately, PL/SQL supports embedded functions. I spent more than an hour trying to find the correct way to use this feature. Yes. forgive me, I am a little dumb. According to my retries, the best position to put your local functions is sharp before the BEGIN symbol. And here's a sample.

set serveroutput on;
CREATE OR REPLACE PROCEDURE tmp12345(v_full_name IN VARCHAR2) AS
	localv varchar2(100);
	-- local function definitaions start ---
	FUNCTION FETCH_REAL_NAME(v_statement_name IN VARCHAR2) RETURN VARCHAR2
	AS
		pattern VARCHAR2(100) := '^(Dr|Ms|Mx|Mr|Mrs)\s+';
		full_name varchar2(100);
	BEGIN
		-- replace possible multiple spaces to one space
		full_name := TRIM(REGEXP_REPLACE(v_statement_name, '\s+',  ' '));
		IF (REGEXP_LIKE(full_name, pattern, 'i')) THEN
			-- REGEXP_REPLACE(string, pattern [, replacement_string [, start_position [, nth_appearance [, match_parameter ] ] ] ]) 
			RETURN REGEXP_REPLACE(full_name, pattern, '', 1, 0, 'i');
		ELSE
			RETURN full_name;
		END IF;
	END;
	FUNCTION FETCH_MIDDLE_NAME(full_name IN VARCHAR) RETURN VARCHAR AS
		middle_name VARCHAR2(100);
	BEGIN
		middle_name := SUBSTR(full_name, INSTR(full_name, ' ') + 1, INSTR(full_name, ' ', 1, 2) - INSTR(full_name, ' ') - 1);
		IF (LENGTH(middle_name) > 10) THEN
			-- return initial instead
			RETURN SUBSTR(middle_name, 1, 1);
		ELSE
			RETURN middle_name;
		END IF;
	END;
	-- local functions definitaions end ---
BEGIN
	-- main logic here
	localv := v_full_name;
	DBMS_OUTPUT.PUT_LINE(localv);
	DBMS_OUTPUT.PUT_LINE(FETCH_MIDDLE_NAME(FETCH_REAL_NAME(v_full_name)));
END;
/

In MySQL, we can

SELECT IF(A IS NULL, "something", A) FROM some_table;

If you want to do a similar thing in PL/SQL, you need to

SELECT (CASE WHEN A IS NULL THEN "something" ELSE A END) FROM some_table;

If you want to get the first non-null value from several fields, you have a better choice than using the CASE keyword.

SELECT COALESCE(A, B) FROM some_table

see more information about the Oracle COALESCE function