COSC 5050
Week Seven

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

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)
Jiangping Wang
Webster University Distributed Database Applications

Native dynamic SQL
Is an integral part of the PL/SQL language itself
Significantly simpler to user and faster
EXECUTE IMMEDIATE statement
Execute a specified SQL statement immediately
OPEN FOR statement
Perform multiple-row dynamic queries
Webster University Distributed Database Applications
Jiangping Wang

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;
Jiangping Wang
Webster University Distributed Database Applications

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)');
Jiangping Wang
Webster University Distributed Database Applications

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;
Jiangping Wang
Webster University Distributed Database Applications

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
PL/SQL engine replaces the various placeholders with the values in the
USING clause
EXECUTE IMMEDIATE
'UPDATE ' || NVL (sch, USER) || '.' || tab ||
END;
/
' SET ' || col || ' = :the_value
WHERE ' || NVL (whr, '1=1')
USING val;
RETURN SQL%ROWCOUNT;
Jiangping Wang
Webster University Distributed Database Applications

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;
END;
/
DBMS_OUTPUT.put_line (
'Employee ' || v_name || ' has ' || v_apptcount ||
' appointments on ' || TO_CHAR (SYSDATE));
Jiangping Wang
Webster University Distributed Database Applications

Extend cursor variables to support dynamic SQL 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;
Jiangping Wang
Webster University Distributed Database Applications

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;
/
Webster University Distributed Database Applications
Jiangping Wang

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;
END LOOP;
CLOSE cv;
END;
END IF;
DBMS_OUTPUT.PUT_LINE (val);
/
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, '-'));
Webster University Distributed Database Applications
Jiangping Wang

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;
Webster University Distributed Database Applications
Jiangping Wang

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;
Jiangping Wang
Webster University Distributed Database Applications

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;
Jiangping Wang
Webster University Distributed Database Applications

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
…
Jiangping Wang
Webster University Distributed Database Applications

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
Jiangping Wang
Webster University Distributed Database Applications

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;
/
Webster University Distributed Database Applications
Jiangping Wang

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;
/
Webster University Distributed Database Applications
Jiangping Wang

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;
Jiangping Wang
Webster University Distributed Database Applications

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
Jiangping Wang
Webster University Distributed Database Applications

Object programming features
Creating base type and subtype
Creating object
Storing, retrieving, and using persistent objects
Webster University Distributed Database Applications
Jiangping Wang

Webster University Distributed Database Applications
Jiangping Wang

Webster University Distributed Database Applications
Jiangping Wang

Webster University Distributed Database Applications
Jiangping Wang

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;
/
Webster University Distributed Database Applications
Jiangping Wang

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
);
/
Jiangping Wang
Webster University Distributed Database Applications

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;
/
Jiangping Wang
Webster University Distributed Database Applications

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());
END;
DBMS_OUTPUT.PUT_LINE('ITEM: ' || generic_item.print());
Webster University Distributed Database Applications
Jiangping Wang

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'));
Webster University Distributed Database Applications
Jiangping Wang

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
SELECT VALUE(c)
FROM catalog_items c;
SELECT VALUE(c).id, VALUE(c).print()
FROM catalog_items c;
Jiangping Wang
Webster University Distributed Database Applications

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);
END;
CLOSE ccur;
Webster University Distributed Database Applications
Jiangping Wang

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

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
ELSE
DBMS_OUTPUT.PUT_LINE('Found a serial with ISSN '
|| TREAT(arec.item AS serial_t).issn);
DBMS_OUTPUT.PUT_LINE('Found unknown catalog item');
END CASE;
END;
END LOOP;
Jiangping Wang
Webster University Distributed Database Applications

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

ASCII
The ASCII Character set: characters 32 – 127.
Webster University Distributed Database Applications
Jiangping Wang

0 1 2 3 4 5 6 7 8 9 A B C D E F
0 NUL SOH STX ETX EOT ENQ ACK BEL BS HT LF VT FF CR SO SI
1 DLE DC1 DC2 DC3 DC4 NAK SYN ETB CAL EM SUB ESC FS GS RS US
2 sp !
” # $ % & ’ ( ) * + , .
/
3 0 1 2 3 4 5 6 7 8 9 : ; < = > ?
4 @ A B C D E F G H I J K L M N O
5 P Q R S T U V W X Y Z [ \ ] ^ _
6 ` a b c d e f g h i j k l m n o
7 p q r s t y v w x y z { | } ~ DEL
Webster University Distributed Database Applications
Jiangping Wang

0 1 2 3 4 5 6 7 8 9 A B C D E F
0
1
2 sp !
” # $ % & ’ ( ) * + , .
/
3 0 1 2 3 4 5 6 7 8 9 : ; < = > ?
4 @ A B C D E F G H I J K L M N O
5 P Q R S T U V W X Y Z [ \ ] ^ _
6 ` a b c d e f g h i j k l m n o
7 p q r s t y v w x y z { | } ~ DEL
8
9
A
NBSP
¡ ¢ £ ¤ ¥ ¦ § ¨ © ª « ¬ ® ¯
B
° ± ² ³ ´ µ ¶ · ¸ ¹ º » ¼ ½ ¾ ¿
C
À Á Â Ã Ä Å Æ Ç È É Ê Ë Ì Í Î Ï
D Ð Ñ Ò Ó Ô Õ Ö × Ø Ù Ú Û Ü Ý Þ ß
E
à á â ã ä å æ ç è é ê ë ì í î ï
F
ð ñ
Webster University
ò ó ô õ ö ÷ ø ù
Distributed Database Applications
ú û ü ý þ ÿ

Unicode is a standard for representing characters
Character encoding with UTF
UTF-8
UTF-16
UTF-32
Webster University Distributed Database Applications
Jiangping Wang

F, 10: Private Use Planes
E: Supplementary Special-Purpose Plane
Unassigned
2: Supplementary Ideographic Plane
1: Supplementary Multilingual Plane
0: Basic Multilingual Plane
Distributed Database Applications
Jiangping Wang
Webster University

Associating characters with values in the code space
Webster University Distributed Database Applications
Jiangping Wang

Three equivalent and interconvertible binary representations
Webster University Distributed Database Applications
Jiangping Wang

Character set
NLS_CHARACTERSET
NLS_NCHAR_CHARACTERSET
Data types
CHAR and VARCHAR
NCHAR and NVARCHAR
Database character set
National character set
Fixed-length
CHAR
NCHAR
Variable-length
VARCHAR2
NVARCHAR2
Webster University Distributed Database Applications
Jiangping Wang

Webster University Distributed Database Applications
Jiangping Wang

Webster University Distributed Database Applications
Jiangping Wang