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Pl Sql Best Practices Error Handling


Here is an exception section that clearly expects a DUP_VAL_ON_INDEX error to be raised but buries that information in WHEN OTHERS : EXCEPTION WHEN OTHERS THEN IF SQLCODE Second, put into place clear guidelines for raising exceptions, backed up by a generic raise program that takes the guesswork out of an individual developer's efforts. Deciding which errors should be handled and which can go unhandled in any given block of code. 2. The package body includes a WHEN OTHERS exception section (see Listing 1). this page

Welcome Account Sign Out Sign In/Register Help Products Solutions Downloads Store Support Training Partners About OTN Oracle Technology Network Oracle Magazine Issue Archive Oracle Magazine Online 2016 2015 2014 2013 2012 Next Steps READ Part 1 of this article more Feuerstein on OTNDOWNLOAD files callstack.sql errpkg.pkg msginfo.fmb msginfo.fmx msginfo.pkg msginfo.sql Document Exceptions That Need Handling When a developer designs a program Use Named Constants Oracle allocates 1,000 error numbers, between -20,000 and -20,999, for application-specific errors (such as "Employee must be 18 years old" or "Reservation date must be in the future"). PKG-03: Freeze and build package specifications before implementing package bodies.

Pl/sql Logging Best Practices

When writing functions, you may well decide that in the case of certain exceptions, you will want to return a value such as NULL, rather than allow an exception to propagate PL/SQL behaves like this (or, to be more accurate, the Oracle PL/SQL development team decided to implement exception handling like this) because until local variables and constants are fully elaborated, you This program asks for a customer ID, when the user enters an invalid ID, the exception invalid_id is raised.

A movie about people moving at the speed of light Why do units (from physics) behave like numbers? Example: package body foo as function implode ( i_foo_id number ) return implode_id as not_implodable exception; implode_id number; begin if not is_implodable(i_foo_id) then raise not_implodable; end if; //Implode logic here. It is entirely feasible within the PL/SQL language to build an application that fully protects the user and the database from errors. Exception Handling In Oracle 11g You can, however, hide these types of exceptions from your high-level application code in two ways.

Discover unlimited learning on demand for around $1/day. Pl Sql Exception Handling Examples Following is the simple syntax of raising an exception: DECLARE exception_name EXCEPTION; BEGIN IF condition THEN RAISE exception_name; END IF; EXCEPTION WHEN exception_name THEN statement; END; You can use above syntax Package Construction PKG-01: Group related data structures and functionality together in a single package. http://www.oracle.com/technetwork/issue-archive/2008/08-jul/o48plsql-101224.html Safari Logo Start Free Trial Sign In Support Enterprise Pricing Apps Explore Tour Prev CTL-11: Label and highlight GOTOs if using this normally unnecessary construct.

Your cache administrator is webmaster. Pl/sql Exception When Others I want to... Safari Logo Start Free Trial Sign In Support Enterprise Pricing Apps Explore Tour Prev A.4. Note also that Oracle considers this behavior a bug (number 5658561).

Pl Sql Exception Handling Examples

If the department does not exist, she submits a request to add a new department. https://www.safaribooksonline.com/library/view/oracle-plsql-best/0596001215/ch05.html Both changes require substantial changes to the exception sections. Pl/sql Logging Best Practices Code Listing 1: Package assigning a too-large value to a package-level string PACKAGE valerr IS FUNCTION little_name RETURN VARCHAR2; END valerr; PACKAGE BODY valerr IS g_name VARCHAR2 (1) := 'Liu'; Oracle Function Exception Return First, I supply the condition that I wish to assert.

You can then feed this information to an error handler, to provide as much information as possible to the person debugging your code. this website You might, on the other hand, decide that you want an exception section only at the outer-most block. Would there be no time in a universe with only light? Listing 1 contains a simple assertion program that checks to see if a condition is TRUE. Oracle Function Exception Return Null

STYL-08: Use vertical code alignment to emphasize vertical relationships. This recommendation is easy to demonstrate with the ubiquitous SELECT INTO lookup query. Which error? Get More Info The result?

Consider the following rewrite of the previous exception section: EXCEPTION WHEN NO_DATA_FOUND THEN errpkg.handle ( 'No company for id ' || TO_CHAR (v_id), log => Pl Sql Logging Example Writing SQL in PL/SQL SQL-00: Establish and follow clear rules for how to write SQL in your application. 6.1. This is very poorly structured code: it's hard to understand and hard to maintain.

It is not a best practice for functions to return after raising and error in PL/SQL.

Words that are anagrams of themselves When did the coloured shoulder pauldrons on stormtroopers first appear? EXC-00: Set guidelines for application-wide error handling before you start coding. Raising Exceptions 5.2. Oracle Pl Sql Best Practices Output the Hebrew alphabet Was the Boeing 747 designed to be supersonic?

Because this statement can have its own exception section, you can immediately trap the exception and either fix the problem or log and reraise the error. Coding Style and Conventions STYL-01: Adopt a consistent, readable format that is easy to maintain. Coding Style and Conventions A.3. see here These two exceptions need different handling.

So let's agree: place application code inside a WHEN clause only when it's necessary to handle the error (usually, this involves logging and reraising the exception). Browse other questions tagged stored-procedures exception-handling plsql or ask your own question. Since raising the error exits the call stack, is there any good reason to return null anyways? Package Construction A.9.

For example, in one way to apply this rule to UTL_FILE.GET_LINE, the process_file procedure in Listing 5 reads the contents of a file and then processes each line it read. A user-defined exception must be declared and then raised explicitly, using either a RAISE statement or the procedure DBMS_STANDARD.RAISE_APPLICATION_ERROR. The procedure will use native dynamic SQL (lines 18 through 19) to raise whatever exception I name in the fourth parameter (lines 5 through 6). This package keeps track of the call stack, by recording in a PL/SQL table each piece of code as it "announces" itself.

VALUE_ERROR 06502 -6502 It is raised when an arithmetic, conversion, truncation, or size-constraint error occurs. DBMS_OUTPUT 9.2. Situations that cause programs to fail. I have a PL/SQL block similar to this DECLARE --work variables PROCEDURE p1(in_parameter1, out_parameter1, out_parameter2...) IS BEGIN --do stuff --select ( ... ) into ( ... ) from t1 where (

STYL-06: Self-document using block and loop labels. I am always looking to improve my code so I recently turned on showing warning. You are previewing Oracle PL/SQL Best Practices. Using Variables and Data Structures 3.3.

stored-procedures exception-handling plsql share|improve this question edited Sep 10 '11 at 19:56 APC 87.3k1384184 asked Sep 9 '11 at 10:52 bruno 1,798816 add a comment| 3 Answers 3 active oldest votes ZERO_DIVIDE 01476 1476 It is raised when an attempt is made to divide a number by zero. That approach does not, however, give you access to the data values within a user's application session. CASE_NOT_FOUND 06592 -6592 It is raised when none of the choices in the WHEN clauses of a CASE statement is selected, and there is no ELSE clause.

PKG-09: Simplify and encourage module usage using overloading to widen calling options. The best way is to put them in a relational table, provide an interface to that table, and, most important, build a utility that generates all the associated code (exception, error No errors.