Oracle PL/SQL Programming: A Developer's Workbook

Intermediate

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1-7.	Use the %TYPE anchoring attribute against a PL/SQL variable, just as you would anchor to the column of a table: CREATE OR REPLACE PACKAGE types IS dollar_amount NUMBER(20,2); END; / DECLARE my_dollars types.dollar_amount%TYPE; BEGIN ... END;
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1-8.	The statements about the DATE datatype are: Both true and false. Prior to Oracle 7.3, the maximum date was January 1, 4712. In later versions of Oracle, the maximum date has now been set to December 31, 9999. True True. The Oracle DATE is really a date-time data structure. False. A date variable records the time down only to the nearest second. False. No matter how you specify the date value, the internal format always uses a four-digit year.
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1-9.	The thing to remember when using a SUBTYPE is that you do not include a %TYPE anchoring attribute. A subtype already is a type. Here is the solution: CREATE OR REPLACE PACKAGE types IS SUBTYPE dollar_amount_t IS NUMBER; END; / DECLARE my_dollars types.dollar_amount_t; BEGIN ... END;
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1-10.	You can’t anchor (use %TYPE) against a CONSTANT; it must be a variable.
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1-11.	Unlike the folks who wrote the PL/SQL language, we developers are not allowed to “constrain” our own SUBTYPEs. In other words, after the IS keyword you cannot supply a datatype declaration that limits the size or length explicitly. Note that this restriction is relaxed in Oracle8i .
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1-12.	You receive this error: ORA-06502: PL/SQL: numeric or value error because a variable assigned the type SIGNTYPE can have only one of three ...