© 2007 by Prentice Hall7-1 Introduction to Oracle 10g Chapter 7 Using PL/SQL to Your Advantage James Perry and Gerald Post

© 2007 by Prentice Hall7-1

Introduction to Oracle 10gChapter 7Using PL/SQL to Your Advantage

James Perry and Gerald Post


Chapter Outline

• Introducing PL/SQL• Understanding Anonymous Blocks• Creating Anonymous Blocks• Understanding Explicit Cursors• Introducing Named Blocks• Creating, Using, Listing, and Dropping

Functions• Creating Procedures


Table 7.1

Oracle Error Code

Meaning

ORA-0001 Unique constraint violated.

ORA-1001 Illegal cursor operation.

ORA-1403 No data found.

ORA-1422 A SELECT INTO statement returns more than one row.

ORA-1476 Division by zero has occurred.

ORA-1722 Conversion to a number failed; (Attempt to convert a character string, for instance.)

ORA-6502 Truncation, conversion error, or arithmetic error.

ORA-6511 Attempt to open a cursor that is already open.


Table 7.2

Exception name to test

Meaning

ACCESS_INTO_NULL Attempted to assign a value to an attribute of an uninitialized object.

CASE_NOT_FOUND None of the WHEN clauses of a CASE structure was selected and there was no ELSE default clause.

CURSOR_ALREADY_OPEN

Program tried to open a cursor that is already open.

INVALID_CURSOR Program tried to perform an illegal cursor activity such as closing an open cursor.

NO_DATA_FOUND A SELECT INTO statement returns zero rows.

ROWTYPE_MISMATCH A cursor variable and a PL/SQL variable have incompatible data types.

TOO_MANY_ROWS A SELECT INTO statement returned more than one row.

VALUE_ERROR A conversion, arithmetic, truncation, or size-constraint error occurred. (For example, an attempt to select a long character column into a shorter PL/SQL variable causes this exception.)

ZERO_DIVIDE Attempted to divide a number by zero.


Table 7.3

Base Salary to Dependent Ratio

Base Salary Increase

$0 – $1,000 10%

$1,001 – $1,500 8%

$1,501 – $2,000 6%

$2,001 – $3,000 3%

Above $3,000 No increase


7.1 PL/SQL processing


7.2 Example PL/SQL block


7.3 Initializing the Redwood Realty database


7.4 An anonymous PL/SQL block


7.5 Executing an anonymous PL/SQL block


error message displayed by the exception-handling code

SQLERRM is the text of the error message

7.6 A run-time error using an implicit cursor


two hyphens turn the SELECT statement into a comment

7.7 Exploring exception handling


7.8 A completed PL/SQL block containing an explicit cursor


7.9 Testing an anonymous PL/SQL block containing an explicit cursor


cursor definition

cursor FOR loop

7.10 Using a cursor FOR loop with an explicit cursor


TrueFalse Condition?

<statements> <statements>

enter

exit

7.11 IF statement logic


SalaryRatio <= 1000

SalaryRatio <= 1500

SalaryRatio <= 2000

SalaryRatio <= 3000

Increment by 10%

Increment by 8%

Increment by 6%

Increment by 3% (no increment)

Enter

True

True

True

True

False

False

False

False

Exit

7.12 Business rules logic diagram


7.13 Implementing a DML statement in a PL/SQL code block


7.14 Messages indicate the salary increment for each agent


7.15 Displaying compile-time error information.


7.16 Calling a user-defined function


7.17 Error messages indicating an invalid AgentID value


new code line

new code lines

new code line

7.18 Modified Age function


modified Age function

testing the Age function with good and bad data values

7.19 Testing the modified Age function


User_Source description

Age function source code stored in the database

7.20 Displaying User_Source’s structure and information about a stored function


7.21 Completed ForSale source code (shown in Notepad)


7.22 Message indicating the procedure is syntax-error free


call to ForSale without an argument and resulting error messages

7.23 Testing the ForSale procedure


new line

new line

three new lines

7.24 Testing the newly modified ForSale procedure


7.25 Displaying a procedure’s source code

Documents

© 2007 by Prentice Hall7-1 Introduction to Oracle 10g Chapter 7 Using PL/SQL to Your Advantage James Perry and Gerald Post