View
31
Download
1
Category
Preview:
DESCRIPTION
Distributed Database Applications. COSC 5050 Week Seven. Outline. Dynamic SQL and dynamic PL/SQL NDS statements EXCUTE IMMEDIATE OPEN FOR Oracle's object features Globalization and localization. Dynamic SQL and PL/SQL. Constructed and executed at runtime - PowerPoint PPT Presentation
Citation preview
Distributed Database Applications
COSC 5050Week Seven
Jiangping WangWebster University Distributed Database Applications
Outline
Dynamic SQL and dynamic PL/SQLNDS statements
EXCUTE IMMEDIATEOPEN FOR
Oracle's object featuresGlobalization and localization
Jiangping WangWebster University Distributed 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 statementsBuild back-ends applications
DBMS_SQL packageNative Dynamic SQL (NDS)
Jiangping WangWebster University Distributed Database Applications
NDS Statement
Native dynamic SQLIs an integral part of the PL/SQL language itselfSignificantly simpler to user and faster
EXECUTE IMMEDIATE statementExecute a specified SQL statement immediately
OPEN FOR statementPerform multiple-row dynamic queries
Jiangping WangWebster University Distributed 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;
Jiangping WangWebster University Distributed 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)');
Jiangping WangWebster University Distributed Database Applications
EXECUTE IMMEDIATE Statement
CREATE OR REPLACE FUNCTION tabCount ( tab IN VARCHAR2, whr IN VARCHAR2 := NULL, sch IN VARCHAR2 := NULL) RETURN INTEGERIS 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 WangWebster University Distributed Database Applications
EXECUTE IMMEDIATE Statement
Bind VariableCREATE OR REPLACE FUNCTION updNVal ( tab IN VARCHAR2, col IN VARCHAR2, val IN NUMBER, whr IN VARCHAR2 := NULL, sch IN VARCHAR2 := NULL) RETURN PLS_INTEGERISBEGIN 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
Jiangping WangWebster University Distributed Database Applications
EXECUTE IMMEDIATE Statement
Bind VariableCREATE 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;/
Jiangping WangWebster University Distributed 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
Jiangping WangWebster University Distributed Database Applications
OPEN FOR Statementcreate 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;/
Jiangping WangWebster University Distributed 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;/
Jiangping WangWebster University Distributed Database Applications
FETCH into VariablesDeclare
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;
Jiangping WangWebster University Distributed Database Applications
FETCH into RecordsDeclare
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 WangWebster University Distributed Database Applications
FETCH into Recordscreate or replace package company_strucis 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 WangWebster University Distributed 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 …
Jiangping WangWebster University Distributed Database Applications
Binding Variables
Binding utilizes placeholders and USING clauseEXECUTE IMMEDIATE
'UPDATE ' || tab || ' SET sal = :new_sal' USING v_sal;
Concatenation adds values directly to the SQL stringEXECUTE IMMEDIATE
'UPDATE ' || tab || ' SET sal = ' || v_sal;
Binding is fasterBinding is easier to write and maintainBinding negates the chance of code injection
Jiangping WangWebster University Distributed Database Applications
Code InjectionCREATE 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;/
Jiangping WangWebster University Distributed Database Applications
Avoid Code InjectionCREATE 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;/
Jiangping WangWebster University Distributed Database Applications
Argument ModesIN, 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 WangWebster University Distributed Database Applications
Dynamic SQL and Static SQL
More versatile than plain embedded SQL programsCan be built interactively with input from users having little or no knowledge of SQL
For highly flexible applications
Require complex codingUse of special data structuresMore runtime processing
Jiangping WangWebster University Distributed Database Applications
Oracle's Object Features
Object programming featuresCreating base type and subtypeCreating objectStoring, retrieving, and using persistent objects
Jiangping WangWebster University Distributed Database Applications
Object Programming Features
Jiangping WangWebster University Distributed Database Applications
Object Programming Features
Jiangping WangWebster University Distributed Database Applications
Library Catalog Type Hierarchy
Jiangping WangWebster University Distributed 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;/
Jiangping WangWebster University Distributed 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);/
Jiangping WangWebster University Distributed 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;/
Jiangping WangWebster University Distributed 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;
Jiangping WangWebster University Distributed 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_itemsdesc 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'));
Jiangping WangWebster University Distributed Database Applications
The VALUE functionAccepts a single argument, which must be a table alias in the current FROM clauseReturns 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;
Jiangping WangWebster University Distributed 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;
Jiangping WangWebster University Distributed Database Applications
The TREAT functionTreat 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;/
Jiangping WangWebster University Distributed 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;
Jiangping Wang
Globalization and Localization
Unicode supportVariable precision
Single-byte vs. multi-byte
Sorting orderNon-character data
Date and timeCurrency
Webster University Distributed Database Applications
Jiangping Wang
Character CodesASCII
The ASCII Character set: characters 32 – 127.
Webster University Distributed Database Applications
Jiangping Wang
ASCII 19670 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
ISO 8859-10 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 ò ó ô õ ö ÷ ø ù ú û ü ý þ ÿWebster University Distributed Database Applications
Jiangping Wang
Unicode Support
Unicode is a standard for representing charactersCharacter encoding with UTF
UTF-8UTF-16UTF-32
Webster University Distributed Database Applications
Jiangping Wang
Unicode Encoding Space
0: Basic Multilingual Plane
1: Supplementary Multilingual Plane2: Supplementary Ideographic Plane
E: Supplementary Special-Purpose Plane
F, 10: Private Use Planes
Unassigned
Webster University Distributed Database Applications
Jiangping Wang
Associating characters with values in the code space
Encoding Characters
Webster University Distributed Database Applications
Jiangping Wang
Three equivalent and interconvertible binary representations
Encoding Forms
Webster University Distributed Database Applications
Jiangping Wang
Oracle Character Sets
Character setNLS_CHARACTERSETNLS_NCHAR_CHARACTERSET
Data typesCHAR and VARCHARNCHAR and NVARCHAR
Fixed-length Variable-length
Database character set
CHAR VARCHAR2
National character set NCHAR NVARCHAR2
Webster University Distributed Database Applications
Jiangping Wang
Oracle Character Sets
Webster University Distributed Database Applications
Jiangping Wang
Unicode Support
Webster University Distributed Database Applications
Recommended