Let’s take a look at PL/SQL Character String Functions

• SUBSTR: extracts a specific number of characters from a string, starting at a given point

extracted_string :=

SUBSTR(string_being_searched,

starting_point,

number_of_characters_to_extract);

s_first_name := SUBSTR(‘Sarah Miller’, 1,5);

Debugging PL/SQL Programs

• Syntax error

• Does not follow language guidelines

• Causes a PLS- compile error

• Examples: misspelling a reserved word, using a function incorrectly

• Logic error

• Program compiles correctly, but does not give correct output

Locating and Correcting Syntax Errors

• Isolate the line that is causing the error

• This may be before or after the line that is flagged by the compiler

• Comment out lines as necessary until program runs

• One error may cause several cascading errors, so re-run program after fixing each error