MySQL – No Records in Mysql.func Table Despite Stored Functions

functionsMySQLmysql-5.5stored-procedures

When i am creating a user defined function in one of my mysql server, it's not creating any row in mysql.func table . Even though i have multiple functions in my mysql server , this table is empty . Can someone explain me why its not getting logged . it should create row like mysql.proc table right whenever we create any stored procedure. I am using mysql 5.5.40. Thanks in advance.

Best Answer

All stored procedures and stored functions, whose code is written in the MySQL Stored Procedure Language, reside in mysql.proc.

You can see how many of each with this

SELECT COUNT(1) rowcount,type
FROM mysql.proc GROUP BY type;

The only time I have ever seen mysql.func is in context with AGGREGATE functions:

According to MySQL Documentation on CREATE FUNCTION Syntax for User-Defined Functions

An AGGREGATE function works exactly like a native MySQL aggregate (summary) function such as SUM or COUNT(). For AGGREGATE to work, your mysql.func table must contain a type column. If your mysql.func table does not have this column, you should run the mysql_upgrade program to create it (see Section 4.4.7, “mysql_upgrade — Check and Upgrade MySQL Tables”).

My guess is that mysql.func stores AGGREGATE functions and not regular functions. Evidently, you would create some UDF in C/C++ and register it in mysql.func using the CREATE AGGREGATE FUNCTION syntax.

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Sql-server – Support both stored procedures and functions with same TSQL code base

Sounds like you've already made the decision to use T-SQL for your back-end. For OWASP reasons, you are correct in that calling only stored procedures from your data access layer is the safest approach to avoid SQL injection.

Stored procedures and functions are similar in that you can pass arguments for the parameter list. They also can do similar things. Code re-use is a good thing and will save you in the end when fixing bugs or making enhancements in the future. So find the logic that is similar and re-factor that code to functions. If you want to return tables (single result set), use table based functions. If you want to return single values, use scalar functions. Note, you won't be able to perform permanent environment changes with functions (no CRUD operations are allowed... CREATE/INSERT, READ, UPDATE, DELETE). It's also good practice to wrap your stored procedures with error/exception handling and return those exceptions to the server, to let your logging handle them appropriately. Also note that it's common to return multiple result sets in a single call to a stored procedure (3 SELECT statements for example). In your application code, you'd handle each table individually in the response.

Here are some differences:

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Sql-server – Stored Procedure Create Table from Variable with Variable Constraint

Your logic seems fine, you are getting a syntax error because you aren't delimiting your strings correctly.

[PeriodClosedUID] [varchar](3) NULL,)' <-- problem

Also it's very helpful to be liberal with carriage returns and indenting, so problems like this aren't hidden 4 screens over and only accessible via horizontal scrollbar.

CREATE PROCEDURE dbo.procFinancialPeriodTable -- always use schema prefix
    @TABLENAME SYSNAME
AS
BEGIN -- use body wrappers around whole body
  SET NOCOUNT ON; -- put this at the beginning - no point in setting it at the end

  DECLARE @SQL NVARCHAR(MAX); -- dynamic SQL should always be Unicode

  SELECT @SQL = 'CREATE TABLE dbo.' + QUOTENAME(@TABLENAME) + '('
    + '[ID] [int] IDENTITY(1,1) NOT NULL,[FinPeriodNr] [int] NOT NULL,
       [FinCurrentPeriod] [bit] NULL,[FinStart] [date] NULL,
       [FinEnd] [date] NULL,[FinStatusOpen] [bit] NOT NULL,
       [PeriodClosedTS] [smalldatetime] NULL,[PeriodClosedUID] [varchar](3) NULL,
       CONSTRAINT [PK_FinancialPeriod_' + @TABLENAME + '_1] PRIMARY KEY CLUSTERED(
         [FinPeriodNr]));'; -- all those options you specified were verbose defaults

  EXEC sp_executesql @sql; -- instead of EXEC(@sql)
END
GO

Some links:

Best Answer

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Sql-server – Support both stored procedures and functions with same TSQL code base

Sql-server – Stored Procedure Create Table from Variable with Variable Constraint

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