May 2000
Intermediate to advanced
594 pages
11h 32m
English
Content preview from Oracle PL/SQL Programming: A Developer's Workbook
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Expert
1-16. | Why does this code compile? DECLARE sysdate NUMBER; BEGIN sysdate := 1; END; But this code does not? DECLARE then NUMBER; BEGIN then := 1; END; |
1-17. | How can you get around this restriction and declare SUBTYPEs which are, in effect, constrained? To be specific, I want to declare a subtype called primary_key_t that limits the size of any variable declared with that type to NUMBER(6). |
1-18. | The NULL value in Oracle is handled differently from other values. One could even say that there is no such thing as a “NULL value.” (NULL means “indeterminate.”) Name three rules that apply to NULLs when doing comparisons. |
1-19. | What special operators does Oracle provide for dealing with NULLs? |