一个例子 看了之后感觉对自己很有帮助
    /* File on web: justonce.sql */
    CREATE OR REPLACE PACKAGE BODY justonce
    IS
       TYPE desc_t IS TABLE OF hairstyles.description%TYPE
          INDEX BY BINARY_INTEGER;
       descriptions   desc_t;
    
       FUNCTION description (code_in IN hairstyles.code%TYPE)
          RETURN hairstyles.description%TYPE
       IS
          return_value   hairstyles.description%TYPE;
    
          FUNCTION desc_from_database RETURN hairstyles.description%TYPE
          IS
             CURSOR desc_cur IS
                SELECT description FROM hairstyles WHERE code = code_in;
             desc_rec   desc_cur%ROWTYPE;
          BEGIN
             OPEN desc_cur;
             FETCH desc_cur INTO desc_rec;
             CLOSE desc_cur;
             RETURN desc_rec.description;
          END;
       BEGIN
          RETURN descriptions (code_in);
       EXCEPTION
          WHEN NO_DATA_FOUND THEN
             descriptions (code_in) := desc_from_database;
             RETURN descriptions (code_in);
       END;
    END justonce;