Plsql null

Get rid of mutating table trigger errors with the compound trigger. December 13, When something mutates, it is changing. Something that is changing is hard to analyze and to quantify. In particular, this error occurs when a row-level trigger attempts to read or write the table from which the trigger was fired.

Fortunately, the same restriction does not apply in statement-level triggers. In this post, I demonstrate the kind of scenario that will result in an ORA errors. I then show the "traditional" solution, using a collection defined in a package. Then I demonstrate how to use the compound trigger, added in Oracle Database 11g Release1, to solve the problem much more simply. All the code shown in this example may be found in this LiveSQL script.

Read more. October 31, That's the default and only setting for cursor FOR loop optimizations. It offers a sweet spot of improved performance over row-by-row and not-too-much PGA memory consumption. Test to see if that's fast enough likely will be for many cases. If not, try higher values until you reach the performance level you need - and you are not consuming too much PGA memory.

Don't hard-code the limit value: make it a parameter to your subprogram or a constant in a package specification. Don't put anything in the collection you don't need. So, the first thing to do is to decide very carefully where and when you want to allow nulls. If a column's value should never be null, then define it that way.

If you are writing a subprogram procedure or function and a parameter's value should never be null, you cannot add NOT NULL to the parameter definition. Instead, you will need to do one of the following:. Use a datatype for the parameter that cannot be null. See the examples below. Add code to your subprogram to check or assert that the actual argument value is not null. Then, you declare your own subtype and make that new datatype not-nullable. Let's take a look:. Note that the exceptions raised above occur before the procedure is even executed, so the exception handler of the procedure cannot trap the exception you do not see "Error!

That may be just what you want. But if you cannot use a NOT NULL datatype for your parameter or you want to be able to trap the exception inside the subprogram, then you should write your own assertion code that runs right at the top of the subprogram. Here's an example:. Better yet is to use a predefined and application-standard assertion package. That way, your code could look more like this:. Don't have an assertion package?

No problem! Grab mine from LiveSQL. If you'd like to go down that rabbit hole, start here. Bullet-proof your subprograms with assertion logic to ensure that your program is free of nulls when that is how it should be.

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