PL/SQL Coding Guidelines - Part 2
29
PL/SQL & SQL CODING GUIDELINES – PART 2 Larry Nung
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Transcript of PL/SQL Coding Guidelines - Part 2
PL/SQL & SQL CODING GUIDELINES – PART 2Larry Nung
AGENDAVariables & TypesReferenceQ & A
2
VARIABLES & TYPESGeneral
8. TRY TO USE ANCHORED DECLARATIONS FOR VARIABLES,
CONSTANTS AND TYPES.
BADDECLARE
v_empName VARCHAR2(10); BEGIN
… END;
GOODDECLARE
v_empName emp.ename%TYPE; BEGIN
… END;
9.TRY TO HAVE A SINGLE LOCATION TO DEFINE YOUR TYPES.
10. TRY TO USE SUBTYPES FOR CONSTRUCTS USED OFTEN IN YOUR APPLICATION.
BADDECLARE
v_str VARCHAR2(4000); BEGIN
… END;
GOODCREATE OR REPLACE PACKAGE PKG_SUBTYPE AS
SUBTYPE STRING_MAX IS VARCHAR2(4000); END PKG_SUBTYPE;
DECLARE v_str PKG_SUBTYPE.STRING_MAX;
BEGIN ...
END;
11. NEVER INITIALIZE VARIABLES WITH NULL.
BADDECLARE
v_str VARCHAR2(30) := null; BEGIN
... END;
GOODDECLARE
v_str VARCHAR2(30); BEGIN
... END;
12. AVOID COMPARISONS WITH NULL VALUE, CONSIDER USING IS [NOT] NULL.
BADDECLARE
v_str VARCHAR2(30); BEGIN
if v_str = null then …
end if; END;
GOODDECLARE
v_str VARCHAR2(30); BEGIN
if v_str is null then …
end if; END;
13. AVOID INITIALIZING VARIABLES USING FUNCTIONS IN THE DECLARATION SECTION.
BADDECLARE
l_company_name VARCHAR2(30) := util_pck.get_company_name(in_id => 47);
BEGIN …
END;
GOODDECLARE
v_str VARCHAR2(30); BEGIN
<<init>> BEGIN v_str := util_pck.get_company_name(inId => 47); EXCEPTION WHEN VALUE_ERROR THEN ...END init;
END;
14. NEVER OVERLOAD DATA STRUCTURE USAGES.
BAD<<main>> DECLARE
v_str VARCHAR2(30); BEGIN
<<sub>> DECLARE v_str VARCHAR2(4000) ; BEGIN …END sub;
END main;
15. NEVER USE QUOTED IDENTIFIERS.
BAD<<main>> DECLARE
"v_str" VARCHAR2(30) ; BEGIN
…END main;
16. AVOID USING OVERLY SHORT NAMES FOR DECLARED OR IMPLICITLY DECLARED IDENTIFIERS.
17. AVOID THE USE OF ROWID OR UROWID
REFERENCE26
REFERENCE Trivadis PL/SQL & SQL Coding Guidelines
Version 2.0 http://www.trivadis.com/sites/default/files/downlo
ads/PLSQL_and_SQL_Coding_Guidelines_2_0_HiRes.pdf
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Q&A28
QUESTION & ANSWER
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