1. Distributed Database Applications COSC 5050 Week Seven

2. Jiangping Wang Webster UniversityDistributed Database Applications Outline Dynamic SQL and dynamic PL/SQL NDS statements EXCUTE IMMEDIATE OPEN FOR Oracle's object features Globalization and localization

3. Jiangping Wang Webster UniversityDistributed Database Applications Dynamic SQL and PL/SQL Constructed and executed at runtime Stored in character strings that are input to, or built by, the program at runtime Execute DDL statements Build back-ends applications DBMS_SQL package Native Dynamic SQL (NDS)

4. Jiangping Wang Webster UniversityDistributed Database Applications NDS Statement Native dynamic SQL Is an integral part of the PL/SQL language itself Significantly simpler to user and faster Non-query statements (DML and DDL) and PL/SQL blocks EXECUTE IMMEDIATE statement Execute a specified SQL statement immediately OPEN FOR statement Perform multiple-row dynamic queries

5. Jiangping Wang Webster UniversityDistributed Database Applications DDL, DML, Anonymous Blocks declare l_sqlstring varchar2(200); l_plsqlblock varchar2(200); begin execute immediate 'create table execute_table (col1 varchar(10))'; for l_counter in 1..10 loop l_sqlstring := 'insert into execute_table values (''row ' || l_counter || ''')'; execute immediate l_sqlstring; end loop; l_plsqlblock := 'begin for l_rec in (select * from execute_table) loop dbms_output.put_line(l_rec.col1); end loop; end;'; execute immediate l_plsqlblock; execute immediate 'drop table execute_table'; end;

6. Jiangping Wang Webster UniversityDistributed Database Applications EXECUTE IMMEDIATE Statement execute immediate 'create index emp_u_1 on employee (last_name)'; create or replace procedure execddl (ddl_string in varchar2) is begin execute immediate ddl_string; end; exec execddl( 'create index emp_u_i on employee(last_name)');

7. Jiangping Wang Webster UniversityDistributed Database Applications EXECUTE IMMEDIATE Statement CREATE OR REPLACE FUNCTION tabCount ( tab IN VARCHAR2, whr IN VARCHAR2 := NULL, sch IN VARCHAR2 := NULL) RETURN INTEGER IS retval INTEGER; BEGIN EXECUTE IMMEDIATE 'SELECT COUNT(*) FROM ' || NVL (sch, USER) || '.' || tab || ' WHERE ' || NVL (whr, '1=1') INTO retval; RETURN retval; END; / if tabcount ('emp', 'deptno = ' || v_dept) > 100 then dbms_output.put_line('growing fast!'); end if;

8. Jiangping Wang Webster UniversityDistributed Database Applications EXECUTE IMMEDIATE Statement Bind Variable CREATE OR REPLACE FUNCTION updNVal ( tab IN VARCHAR2, col IN VARCHAR2, val IN NUMBER, whr IN VARCHAR2 := NULL, sch IN VARCHAR2 := NULL) RETURN PLS_INTEGER IS BEGIN EXECUTE IMMEDIATE 'UPDATE ' || NVL (sch, USER) || '.' || tab || ' SET ' || col || ' = :the_value WHERE ' || NVL (whr, '1=1') USING val; RETURN SQL%ROWCOUNT; END; / PL/SQL engine replaces the various placeholders with the values in the USING clause

9. Jiangping Wang Webster UniversityDistributed Database Applications EXECUTE IMMEDIATE Statement Bind Variable CREATE OR REPLACE PROCEDURE run_9am_procedure ( id_in IN employee.employee_id%TYPE, hour_in IN INTEGER) IS v_apptcount INTEGER; v_name VARCHAR2 (100); BEGIN EXECUTE IMMEDIATE 'BEGIN ' || TO_CHAR (SYSDATE, 'DAY') || '_set_schedule (:id, :hour, :name, :appts); END;' USING IN id_in, IN hour_in, OUT v_name, OUT v_apptcount; DBMS_OUTPUT.put_line ( 'Employee ' || v_name || ' has ' || v_apptcount || ' appointments on ' || TO_CHAR (SYSDATE)); END; /

10. Jiangping Wang Webster UniversityDistributed Database Applications OPEN FOR Statement create or replace procedure show_parts_inventory ( parts_table in varchar2, where_n in varchar2 := null) is type query_curtype is ref cursor; dyncur query_curtype; begin open dyncur for ‘select * from ’ || parts_table ‘where ’ || nvl(where_in, ‘1=1’); … end; Extend cursor variables to support dynamic SQL

11. Jiangping Wang Webster UniversityDistributed Database Applications OPEN FOR Statement create or replace procedure show_employee ( table_in in varchar2, where_in in varchar2 := null) is type query_curtype is ref cursor; dyncur query_curtype; emp employee%rowtype; begin open dyncur for 'select * from ' || table_in || ' where ' || nvl (where_in, '1=1'); dbms_output.put_line('Employee list:'); loop fetch dyncur into emp; exit when dyncur%notfound; dbms_output.put_line(emp.lname || ' ' || emp.fname); end loop; close dyncur; end; /

12. Jiangping Wang Webster UniversityDistributed Database Applications Multirow Queries with Cursor Variables CREATE OR REPLACE PROCEDURE showcol ( tab IN VARCHAR2, col IN VARCHAR2, whr IN VARCHAR2 := NULL) IS TYPE cv_type IS REF CURSOR; cv cv_type; val VARCHAR2(32767); BEGIN OPEN cv FOR 'SELECT ' || col || ' FROM ' || tab || ' WHERE ' || NVL (whr, '1 = 1'); LOOP FETCH cv INTO val; EXIT WHEN cv%NOTFOUND; IF cv%ROWCOUNT = 1 THEN DBMS_OUTPUT.PUT_LINE (RPAD ('-', 60, '-')); DBMS_OUTPUT.PUT_LINE ('Contents of '||UPPER(tab)||'.'||UPPER(col)); DBMS_OUTPUT.PUT_LINE (RPAD ('-', 60, '-')); END IF; DBMS_OUTPUT.PUT_LINE (val); END LOOP; CLOSE cv; END; /

13. Jiangping Wang Webster UniversityDistributed Database Applications FETCH into Variables Declare type cv_type is ref cursor; cv cv_type; mega_bucks company.ceo_compensation%type; achieved_by company.cost_cutting%type; Begin Open cv for ‘select ceo_compensation, cost_curtting from company where ’ || nvl (whr, ‘1=1’); loop fetch cv into mega_bucks, achieved_by;

14. Jiangping Wang Webster UniversityDistributed Database Applications FETCH into Records Declare type cv_type is ref cursor; cv cv_type; ceo_info company%rowtype; Begin Open cv for ‘select * from from company where ’ || nvl (whr, ‘1=1’); loop fetch cv into ceo_info;

15. Jiangping Wang Webster UniversityDistributed Database Applications FETCH into Records create or replace package company_struc is type dynsql_curtype is ref cursor; type ceo_info_rt is record ( mega_bucks company.ceo_compensation%type, achieved_by company.cost_cutting%type); declare cv company_struc.dynsql_curtype; rec company_struc.ceo_info_rt; begin open cv for ‘select ceo_eompensatin, cost_cutting from company where ’ || nvl (whr, ‘1=1’); loop fetch cv into rec;

16. Jiangping Wang Webster UniversityDistributed Database Applications The USING Clause in OPEN FOR OPEN cv FOR 'SELECT ' || col || ' FROM ' || tab || ' WHERE ' || dtcol || ' BETWEEN TRUNC (:startdt) AND TRUNC (:enddt)' USING dt1, NVL (dt2, dt1+1); LOOP FETCH cv INTO val; EXIT WHEN cv%NOTFOUND; IF cv%ROWCOUNT = 1 THEN …

17. Jiangping Wang Webster UniversityDistributed Database Applications Binding Variables Binding utilizes placeholders and USING clause EXECUTE IMMEDIATE 'UPDATE ' || tab || ' SET sal = :new_sal' USING v_sal; Concatenation adds values directly to the SQL string EXECUTE IMMEDIATE 'UPDATE ' || tab || ' SET sal = ' || v_sal; Binding is faster Binding is easier to write and maintain Binding negates the chance of code injection

18. Jiangping Wang Webster UniversityDistributed Database Applications Code Injection CREATE OR REPLACE PROCEDURE get_rows ( ssn_in in VARCHAR2 ) IS l_where VARCHAR2(32767); BEGIN l_where := 'ssn = ' || ssn_in; EXECUTE IMMEDIATE 'DECLARE l_row employee%ROWTYPE; BEGIN SELECT * INTO l_row FROM employee WHERE ' || l_where || '; dbms_output.put_line(l_row.lname); END;'; END get_rows; /

19. Jiangping Wang Webster UniversityDistributed Database Applications Avoid Code Injection CREATE OR REPLACE PROCEDURE get_rows ( ssn_in in VARCHAR2 ) IS l_where VARCHAR2(32767); BEGIN l_where := 'ssn = :ssnumber'; EXECUTE IMMEDIATE 'DECLARE l_row employee%ROWTYPE; BEGIN SELECT * INTO l_row FROM employee WHERE ' || l_where || '; dbms_output.put_line(l_row.lname); END;' USING ssn_in; END get_rows; /

20. Jiangping Wang Webster UniversityDistributed Database Applications Argument Modes IN, OUT, IN OUT create or replace procedure wrong_incentive( company_in in integer, new_layoffs in number) is sql_string varchar2(2000); sal_after_layoffs number; begin sql_string := ‘update ceo_compensation set salary = salary + 10 * :layoffs where company_id = :company returning salary into :newsal’; execute immediate sql_string using new_layoffs, company_in, out sal_after_layoffs; dbms_output.put_line (ceo compensation after latest round of layoffs $’ || sal_after_layoffs); end;

21. Jiangping Wang Webster UniversityDistributed Database Applications Duplicate Placeholders create or replace procedure updnumval ( col_in in varchar2, start_in in date, end_in in date, val_in in number) is dml_str varchar2(32767) := 'update emp set ' || col_in || ' := :val where hiredate between :lodate and :hidate and :val is not null'; begin execute immediate dml_str using val_in, start_in, end_in, val_in; end; create or replace procedure updnumval ( col_in in varchar2, start_in in date, end_in in date, val_in in number) is dml_str varchar2(32767) := 'begin update emp set ' || col_in || ' := :val where hiredate between :lodate and :hidate and :val is not null; end; '; begin execute immediate dml_str using val_in, start_in, end_in; end; Dynamic SQL, supply an argument for each placeholder Dynamic PL/SQL block, supply an argument for each unique placeholder

22. Jiangping Wang Webster UniversityDistributed Database Applications Dynamic SQL and Static SQL More versatile than plain embedded SQL programs Can be built interactively with input from users having little or no knowledge of SQL For highly flexible applications Require complex coding Use of special data structures More runtime processing

23. Jiangping Wang Webster UniversityDistributed Database Applications Oracle's Object Features Object programming features Creating base type and subtype Creating object Storing, retrieving, and using persistent objects

24. Jiangping Wang Webster UniversityDistributed Database Applications Object Programming Features

25. Jiangping Wang Webster UniversityDistributed Database Applications Object Programming Features

26. Jiangping Wang Webster UniversityDistributed Database Applications Library Catalog Type Hierarchy

27. Jiangping Wang Webster UniversityDistributed Database Applications Creating Base Type CREATE OR REPLACE TYPE catalog_item_t AS OBJECT ( id INTEGER, title VARCHAR2(4000), NOT INSTANTIABLE MEMBER FUNCTION ck_digit_okay RETURN BOOLEAN, MEMBER FUNCTION print RETURN VARCHAR2 ) NOT INSTANTIABLE NOT FINAL; /

28. Jiangping Wang Webster UniversityDistributed Database Applications Creating Subtype CREATE OR REPLACE TYPE book_t UNDER catalog_item_t ( isbn VARCHAR2(13), pages INTEGER, CONSTRUCTOR FUNCTION book_t ( id IN INTEGER DEFAULT NULL, title IN VARCHAR2 DEFAULT NULL, isbn IN VARCHAR2 DEFAULT NULL, pages IN INTEGER DEFAULT NULL) RETURN SELF AS RESULT, OVERRIDING MEMBER FUNCTION ck_digit_okay RETURN BOOLEAN, OVERRIDING MEMBER FUNCTION print RETURN VARCHAR2 ); /

29. Jiangping Wang Webster UniversityDistributed Database Applications Creating Subtype CREATE OR REPLACE TYPE serial_t UNDER catalog_item_t ( issn VARCHAR2(10), open_or_closed VARCHAR2(1), CONSTRUCTOR FUNCTION serial_t ( id IN INTEGER DEFAULT NULL, title IN VARCHAR2 DEFAULT NULL, issn IN VARCHAR2 DEFAULT NULL, open_or_closed IN VARCHAR2 DEFAULT NULL) RETURN SELF AS RESULT, OVERRIDING MEMBER FUNCTION ck_digit_okay RETURN BOOLEAN, OVERRIDING MEMBER FUNCTION print RETURN VARCHAR2 ) NOT FINAL; /

30. Jiangping Wang Webster UniversityDistributed Database Applications Creating Object DECLARE generic_item catalog_item_t; abook book_t; BEGIN abook := NEW book_t(title => 'Out of the Silent Planet', isbn => '0-6848-238-02'); generic_item := abook; DBMS_OUTPUT.PUT_LINE('BOOK: ' || abook.print()); DBMS_OUTPUT.PUT_LINE('ITEM: ' || generic_item.print()); END;

31. Jiangping Wang Webster UniversityDistributed Database Applications Storing Persistent Objects CREATE TABLE catalog_items OF catalog_item_t (CONSTRAINT catalog_items_pk PRIMARY KEY (id)); CREATE TABLE my_writing_projects ( project_id INTEGER NOT NULL PRIMARY KEY, start_date DATE, working_title VARCHAR2(4000), catalog_item catalog_item_t); DESC catalog_items desc my_writing_projects INSERT INTO catalog_items VALUES (NEW book_t(10003, 'Perelandra', '0-684-82382-9', 222)); INSERT INTO catalog_items VALUES (NEW serial_t(10004, 'Time', '0040-781X', 'O'));

32. Jiangping Wang Webster UniversityDistributed Database Applications The VALUE function Accepts a single argument, which must be a table alias in the current FROM clause Returns an object of the type on which the table is defined Retrieving Persistent Objects SELECT VALUE(c) FROM catalog_items c; SELECT VALUE(c).id, VALUE(c).print() FROM catalog_items c;

33. Jiangping Wang Webster UniversityDistributed Database Applications Retrieving Persistent Objects DECLARE catalog_item catalog_item_t; CURSOR ccur IS SELECT VALUE(c) FROM catalog_items c; BEGIN OPEN ccur; FETCH ccur INTO catalog_item; DBMS_OUTPUT.PUT_LINE('I fetched item #' || catalog_item.id); CLOSE ccur; END;

34. Jiangping Wang Webster UniversityDistributed Database Applications The TREAT function Treat a generic base type object as the more narrowly defined subtype object Object Downcasting DECLARE book book_t; catalog_item catalog_item_t := NEW book_t(); BEGIN book := TREAT(catalog_item AS book_t); END; /

35. Jiangping Wang Webster UniversityDistributed Database Applications Test Object Type DECLARE CURSOR ccur IS SELECT VALUE(c) item FROM catalog_items c; arec ccur%ROWTYPE; BEGIN FOR arec IN ccur LOOP CASE WHEN arec.item IS OF (book_t) THEN DBMS_OUTPUT.PUT_LINE('Found a book with ISBN ' || TREAT(arec.item AS book_t).isbn); WHEN arec.item IS OF (serial_t) THEN DBMS_OUTPUT.PUT_LINE('Found a serial with ISSN ' || TREAT(arec.item AS serial_t).issn); ELSE DBMS_OUTPUT.PUT_LINE('Found unknown catalog item'); END CASE; END LOOP; END;

36. Jiangping Wang Globalization and Localization Unicode support Variable precision Single-byte vs. multi-byte Sorting order Non-character data Date and time Currency Webster UniversityDistributed Database Applications

37. Jiangping Wang Character Codes ASCII The ASCII Character set: characters 32 – 127. Webster UniversityDistributed Database Applications

38. Jiangping Wang ASCII 1967 0123456789ABCDEF 0 NULSOHSTXETXEOTENQACKBELBSHTLFVTFFCRSOSI 1 DLEDC1DC2DC3DC4NAKSYNETBCALEMSUBESCFSGSRSUS 2sp!”#$%&’()*+,-./ 30123456789:;<=>? 4@ABCDEFGHIJKLMNO 5PQRSTUVWXYZ[\] ^_ 6`abcdefghijklmno 7pqrstyvwxyz{|}~ DEL Webster UniversityDistributed Database Applications

39. Jiangping Wang ISO 8859-1 0123456789ABCDEF 0 1 2sp!”#$%&’()*+,-./ 30123456789:;<=>? 4@ABCDEFGHIJKLMNO 5PQRSTUVWXYZ[\] ^_ 6`abcdefghijklmno 7pqrstyvwxyz{|}~ DEL 8 9 A NBSP ¡¢£¤¥¦§¨©ª«¬-®¯ B°±²³´µ¶·¸¹º»¼½¾¿ CÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏ DÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞß Eàáâãäåæçèéêëìíîï Fðñòóôõö÷øùúûüýþÿ Webster UniversityDistributed Database Applications

40. Jiangping Wang Unicode Support Unicode is a standard for representing characters Character encoding with UTF UTF-8 UTF-16 UTF-32 Webster UniversityDistributed Database Applications

41. Jiangping Wang Unicode Encoding Space 0: Basic Multilingual Plane 1: Supplementary Multilingual Plane 2: Supplementary Ideographic Plane E: Supplementary Special-Purpose Plane F, 10: Private Use Planes Unassigned Webster UniversityDistributed Database Applications

42. Jiangping Wang Associating characters with values in the code space Encoding Characters Webster UniversityDistributed Database Applications

43. Jiangping Wang Three equivalent and interconvertible binary representations Encoding Forms Webster UniversityDistributed Database Applications

44. Jiangping Wang Oracle Character Sets Character set NLS_CHARACTERSET NLS_NCHAR_CHARACTERSET Data types CHAR and VARCHAR NCHAR and NVARCHAR Fixed-lengthVariable-length Database character setCHARVARCHAR2 National character setNCHARNVARCHAR2 Webster UniversityDistributed Database Applications

45. Jiangping Wang Oracle Character Sets Webster UniversityDistributed Database Applications

46. Jiangping Wang Unicode Support Webster UniversityDistributed Database Applications