1. Distributed Database Applications COSC 5050 Week Two

2. Jiangping Wang Webster UniversityDistributed Database Applications Outline Data types and composite structures Working with program data Strings Numbers Dates and Timestamps Records and Collections Miscellaneous datatypes

3. Jiangping Wang Webster UniversityDistributed Database Applications Program Data Naming rules Up to 30 characters Start with a letter Can have letters, numerals, $, #, and _ Case-insensitive

4. Jiangping Wang Webster UniversityDistributed Database Applications Oracle Predefined Datatypes CHAR(n) VARCHAR2(n) NUMBER(n) NUMBER(n, m) PLS_INTEGER BOOLEAN DATE

5. Jiangping Wang Webster UniversityDistributed Database Applications Groups of Data Types Scalar types – predefined data types %TYPE attributes Supports types that may be derived from a database table definition Include %TYPE and %ROWTYPE Composite types May be created from TABLES and RECORDS %ROWTYPE These are composite types with a structure that is derived from a base table or a cursor declaration

6. Jiangping Wang Webster UniversityDistributed Database Applications Declaring Program Data Variable l_total_count NUMBER; l_dollar_amount NUMBER (10, 2); l_right_now DATE NOT NULL DEFAULT SYSDATE; l_favorite_flavor VARCHAR2(100) := ‘Anything with chocolate, actually'; TYPE list_of_books_t IS TABLE OF book%ROWTYPE INDEX BY BINARY_INTEGER; oreilly_oracle_books list_of_books_t; Constant l_curr_year CONSTANT PLS_INTEGER := TO_NUMBER(TO_CHAR(SYSDATE, ‘YYYY’)); l_author CONSTANT VARCHAR2(100) DEFAULT ‘Bill Pribyl’;

7. Jiangping Wang Webster UniversityDistributed Database Applications Anchored Declarations Scalar anchoring Based on column or other scalar variable %TYPE l_company_id company.company_id%TYPE emp_id emp.empno%TYPE new_emp emp_id%TYPE Record anchoring Based on table or explicit cursor %ROWTYPE l_book book%ROWTYPE; l_employee employee%rowtype; l_employee emp_cur%rowtype; Benefits of anchored declarations

8. Jiangping Wang Webster UniversityDistributed Database Applications Anchored Declarations Column%TYPE create or replace procedure charge is -- customer.account column is defined as number(7,2) balance customer.account%type; begin balance := 50.12; balance := balance * 1.12; -- what is the value? dbms_output.put_line('balance is : ' || balance); end charge; /

9. Jiangping Wang Webster UniversityDistributed Database Applications Anchored Declarations declare l_employee employee%rowtype; begin select * into l_employee from employee where ssn = '600000001'; dbms_output.put_line(l_employee.fname || ' ' || l_employee.lname); end; declare cursor emp_cur is select fname, lname from employee where ssn = '600000001'; l_employee emp_cur%rowtype; begin open emp_cur; fetch emp_cur into l_employee; dbms_output.put_line(l_employee.fname || ' ' || l_employee.lname); close emp_cur; end;

10. Jiangping Wang Webster UniversityDistributed Database Applications Programmer Defined Subtypes Define subtypes or aliases of predefined datatypes SUBTYPE subtype_name IS base_type SUBTYPE POSITIVE IS BINARY_INTEGER RANGE 1.. 2147483647; SUBTYPE FLOAT IS NUMBER; SUBTYPE big_string IS VARCHAR2(32767);

11. Jiangping Wang Webster UniversityDistributed Database Applications Datatype Conversions Implicit conversation vs. explicit conversion Figure 7-2, page 184 Implicit conversions Table 7-1, page 185 The built-in conversion functions TO_CHAR( ) TO_NUMBER( ) TO_DATE( ) DECLARE a_number NUMBER; BEGIN a_number := '125'; END;

12. Jiangping Wang Webster UniversityDistributed Database Applications Implicit Conversation

13. Jiangping Wang Webster UniversityDistributed Database Applications Strings CHAR(n) feature_name CHAR(100); VARCHAR2(n) small_string VARCHAR2(4); line_of_text VARCHAR2(2000); Fixed-lengthVariable-length Database character setCHARVARCHAR2 National character setNCHARNVARCHAR2

14. Jiangping Wang PL/SQL subtypes and their equivalents Table 8-1, page 194 Webster UniversityDistributed Database Applications String Subtypes SubtypeEquivalent PL/SQL type CHAR VARYINGVARCHAR2 CHARACTERCHAR CHARACTER VARYINGVARCHAR2 NATIONAL CHARNCHAR NATIONAL CHAR VARYINGNVARCHAR2 NATIONAL CHARACTERNCHAR NATIONAL CHARACTER VARYINGNVARCHAR2 NCHAR VARYINGNVARCHAR2 STRINGVARCHAR2 VARCHARVARCHAR2

15. Jiangping Wang Webster UniversityDistributed Database Applications Empty Strings are NULL DECLARE empty_varchar2 VARCHAR2(10) := ''; empty_char CHAR(10) := ''; BEGIN IF empty_varchar2 IS NULL THEN DBMS_OUTPUT.PUT_LINE('empty_varchar2 is NULL'); END IF; IF '' IS NULL THEN DBMS_OUTPUT.PUT_LINE(''''' is NULL'); END IF; IF empty_char IS NULL THEN DBMS_OUTPUT.PUT_LINE('empty_char is NULL'); ELSIF empty_char IS NOT NULL THEN DBMS_OUTPUT.PUT_LINE('empty_char is NOT NULL'); END IF; END; /

16. Jiangping Wang Webster UniversityDistributed Database Applications String Comparisons DECLARE company_name CHAR(30) := 'Feuerstein and Friends'; char_parent_company_name CHAR(35) := 'Feuerstein and Friends'; varchar2_parent_company_name VARCHAR2(35) := 'Feuerstein and Friends'; BEGIN --Compare two CHARs, so blank-padding is used IF company_name = char_parent_company_name THEN DBMS_OUTPUT.PUT_LINE ('first comparison is TRUE'); ELSE DBMS_OUTPUT.PUT_LINE ('first comparison is FALSE'); END IF; --Compare a CHAR and a VARCHAR2, so nonblank-padding is used IF company_name = varchar2_parent_company_name THEN DBMS_OUTPUT.PUT_LINE ('second comparison is TRUE'); ELSE DBMS_OUTPUT.PUT_LINE ('second comparison is FALSE'); END IF; END; /

17. Jiangping Wang Webster UniversityDistributed Database Applications String Functions ASCII, CHR CHR(64) -- which is ‘@’ INSTR DECLARE company_name VARCHAR2(30) := 'Microsoft Inc.'; BEGIN DBMS_OUTPUT.PUT_LINE(INSTR (company_name, 'Inc')); END; LENGTH LENGTH(‘abcd’) -> 4 LENGTH(NULL) -> NULL SUBSTR, LOWER, UPPER, INITCAP CONCAT begin dbms_output.put_line('abc' || 'def' || 'ghi'); dbms_output.put_line(concat(concat('abc','def'),'ghi')); end;

18. Jiangping Wang Webster UniversityDistributed Database Applications Numbers NUMBER NUMBER(precision, scale) NUMBER(9,2) NUMBER(9,11) NUMBER(9,-11) Rounding of values (page 234) PLS_INTEGER Uses native machine arithmetic BINARY_INTEGER Equivalent to PLS_INTEGER (since 10g) Uses platform independent library code (before 10g) Numeric subtypes (page 246)

19. Jiangping Wang Numeric Subtypes Webster UniversityDistributed Database Applications

20. Jiangping Wang Webster UniversityDistributed Database Applications Numeric Functions TO_NUMBER begin dbms_output.put_line(to_number('12345.67')); end; TO_CHAR DECLARE b VARCHAR2(30); BEGIN b := TO_CHAR(123456789.01,'L999G999G999D99'); DBMS_OUTPUT.PUT_LINE(b); END; ABS, CEIL, FLOOR, POWER, SQRT

21. Jiangping Wang Webster UniversityDistributed Database Applications Date and Time DATE TIMESTAMP TIMESTAMP WITH TIME ZONE TIMESTAMP WITH LOCAL TIME ZONE

22. Jiangping Wang Effect of different datetime datatypes Figure 10-1, page 269 Date and Time Webster UniversityDistributed Database Applications

23. Jiangping Wang Comparison of functions that return current data and time Table 10-1, page 272 Webster UniversityDistributed Database Applications Date and Time FunctionTime zoneDatatype returned CURRENT_DATESessionDATE CURRENT_TIMESTAMPSessionTIMESTAMP WITH TIME ZONE LOCALTIMESTAMPSessionTIMESTAMP SYSDATEServerDATE SYSTIMESTAMPServerTIMESTAMP WITH TIME ZONE

24. Jiangping Wang Webster UniversityDistributed Database Applications Date and Time DECLARE today_date DATE := SYSDATE; BEGIN dbms_output.put_line(TO_CHAR(today_date)); END; Format date and time TO_DATE(’12/31/2003’); -- ? TO_CHAR()

25. Jiangping Wang Date/Time Format To display, the Date value is converted from the internal format to a printable string Oracle's default format for Date is DD-MON-YY To covert explicitly TO_CHAR(value, 'MM/DD/YYYY') Change the default Date format alter session set NLS_DATE_FORMAT='MM/DD/YYYY'; Webster UniversityDistributed Database Applications

26. Jiangping Wang Date/Time Format Webster UniversityDistributed Database Applications

27. Jiangping Wang Webster UniversityDistributed Database Applications TIMESTAMP TIMESTAMP datatypes TIMESTAMP DECLARE today_date TIMESTAMP := SYSDATE; BEGIN dbms_output.put_line(TO_CHAR(today_date)); END; DECLARE the_day date := to_date('22-MAR-2006'); BEGIN dbms_output.put_line(the_day); END;

28. Jiangping Wang Webster UniversityDistributed Database Applications Date/Time Functions ADD_MONTHS function BEGIN dbms_output.put_line(add_months(sysdate, 3)); dbms_output.put_line(add_months(sysdate, -3)); END; LAST_DAY function DECLARE the_day date := to_date('28-FEB-2010'); BEGIN dbms_output.put_line(last_day(the_day)); dbms_output.put_line(last_day(sysdate)); END; MONTHS_BETWEEN function DECLARE the_day date := to_date('28-FEB-2010'); BEGIN dbms_output.put_line(months_between(sysdate, the_day)); END;

29. Jiangping Wang Webster UniversityDistributed Database Applications Records Records are composite structures Similar to a row in a database table Record allow you to select specific columns from one or more tables into single data structure

30. Jiangping Wang Webster UniversityDistributed Database Applications Declaring Records Table-based record one_book books%rowtype; l_employee employee%rowtype; Cursor-based record cursor my_books_cur is select * from books where author like ' feuerstein% ' ; one_sf_book my_books_cur%rowtype; cursor emp_cur is select fname, lname from employee where ssn = '600000001'; l_employee emp_cur%rowtype;

31. Jiangping Wang Webster UniversityDistributed Database Applications Declaring Records Programmer-defined record TYPE book_info_rt IS RECORD ( author books.author%TYPE, category VARCHAR2(100), total_page_count POSITIVE); steven_as_author book_info_rt; -- not %ROWTYPE

32. Jiangping Wang Webster UniversityDistributed Database Applications Programmer-Defined Record TYPE customer_sales_rectype IS RECORD (customer_id NUMBER (5), customer_name customer.name%TYPE, total_sales NUMBER (15,2) ); prev_customer_sales_rec customer_sales_rectype; top_customer_rec customer_sales_rectype;

33. Jiangping Wang Webster UniversityDistributed Database Applications Working with Records DECLARE TYPE customer_sales_rectype IS RECORD (customer_id NUMBER (5), customer_name customer.name%TYPE, total_sales NUMBER (15,2) ); top_customer_rec customer_sales_rectype; BEGIN SELECT customer_id, name, SUM(total_sales) INTO top_customer_rec FROM cust_sales_roundup WHERE sold_on < ADD_MONTHS (SYSDATE, -3) GROUP BY customer_id, name; END;

34. Jiangping Wang Webster UniversityDistributed Database Applications Record-Level Operations Copy contents of one record to another Assign a value of NULL to a record with a simple assignment Define and pass record as an argument in a parameter list RETURN a record back through the interface of a function Insert into a database table with record Since Oracle9i Database Release 2

35. Jiangping Wang Webster UniversityDistributed Database Applications Record-Level Operations Cannot use the IS NULL syntax to see if all fields have NULL values Apply IS NULL operator to each field individually Cannot compare two records Compare each field individually

36. Jiangping Wang Webster UniversityDistributed Database Applications Field-Level Operations DECLARE TYPE phone_rectype IS RECORD (area_code VARCHAR2(3), exchange VARCHAR2(3), phone_number VARCHAR2(4) ); TYPE contact_set_rectype IS RECORD (day_phone# phone_rectype, eve_phone# phone_rectype, fax_phone# phone_rectype ); auth_rep_info_rec contact_set_rectype; BEGIN... auth_rep_info_rec.fax_phone#.area_code := auth_rep_info_rec.day_phone#.area_code;... END;

37. Jiangping Wang Webster UniversityDistributed Database Applications Comparing Records To test for record equality, each field has to be compared individually Compare for NULL (first_book.favorite_author = second_book.favorite_author OR (first_book.favorite_author IS NULL AND second_book.favorite_author IS NULL)

38. Jiangping Wang Webster UniversityDistributed Database Applications Collections A collection is a list of items One dimensioned array Define a particular structure using the TYPE statement – datatype Declare the actual collection based on the table type Types of collections Associative arrays Nested tables VARRAYs

39. Jiangping Wang Collections Associative arrays Single-dimensional, unbounded, sparse collections of homogeneous elements PL/SQL only Nested tables Single-dimensional, unbounded collections of homogeneous elements Can be sparse VARRAYs Single-dimensional collections of homogeneous elements always bounded and never sparse Webster UniversityDistributed Database Applications

40. Jiangping Wang Webster UniversityDistributed Database Applications Collections declare type list_of_dates_t is table of date; type list_of_names_t is table of varchar2(100) index by pls_integer; birthdays list_of_dates_t := list_of_dates_t(); happyfamily list_of_names_t; begin birthdays.extend; birthdays(1) := '23-sep-1958'; birthdays.extend; birthdays(2) := '1-oct-1968'; happyfamily(1) := 'Steven'; happyfamily(2) := 'Veva'; happyfamily(4) := 'Chris'; happyfamily(5) := 'Eli'; dbms_output.put_line(birthdays.count); dbms_output.put_line(happyfamily.first); end;

41. Jiangping Wang Webster UniversityDistributed Database Applications Collections DECLARE CURSOR emp_cur IS SELECT * FROM employee; TYPE emp_data_type IS TABLE OF emp_cur%ROWTYPE INDEX BY PLS_INTEGER; emp_table emp_data_type; i pls_integer; emp_id employee.ssn%type; BEGIN i := 1; OPEN emp_cur; LOOP FETCH emp_cur INTO emp_table(i); EXIT WHEN emp_cur%NOTFOUND; dbms_output.put_line(emp_table(i).lname); i := i + 1; END LOOP; CLOSE emp_cur; dbms_output.put_line('Number of employee: ' || emp_table.count); END;

42. Jiangping Wang Webster UniversityDistributed Database Applications Miscellaneous Datatypes Boolean datatype ROWID and UROWID LOB datatype XMLType datatype

43. Jiangping Wang Webster UniversityDistributed Database Applications Boolean Datatype DECLARE b BOOLEAN := FALSE; BEGIN IF b THEN dbms_output.put_line('true'); ELSE dbms_output.put_line('false'); END IF; END; / Oracle RDBMS does not support a Boolean datatype

44. Jiangping Wang Webster UniversityDistributed Database Applications UROWID & ROWID Datatype DECLARE employee_rowid urowid; emp_fname varchar2(20); BEGIN SELECT rowid, fname INTO employee_rowid, emp_fname FROM employee WHERE lname = 'Letterman'; dbms_output.put_line(employee_rowid); dbms_output.put_line(emp_fname); END; /

45. Jiangping Wang Webster UniversityDistributed Database Applications LOB Datatype BFILE File locator point to an operating system file outside the database BLOB, CLOB, NCLOB LOB locator point to a large object stored inside the database

46. Jiangping Wang Webster UniversityDistributed Database Applications XMLType Datatype Use XMLType to define database columns and PL/SQL variables Methods defined on XMLType Instantiate new XMLType values Extract portions of an XML document Manipulate the contents of an XML document

47. Jiangping Wang Webster UniversityDistributed Database Applications XMLType Type CREATE TABLE falls ( fall_id NUMBER, fall XMLType ); INSERT INTO falls VALUES (1, XMLType.CreateXML( ' Munising Falls Alger MI http://michiganwaterfalls.com ') ); SELECT fall_id FROM falls f WHERE f.fall.existsNode('/fall/url') > 0;

48. Jiangping Wang Webster UniversityDistributed Database Applications Homework Create an anonymous PL/SQL block to retrieve data from above database table into a record and display a detailed report of records. Create an anonymous PL/SQL block to retrieve data from above database table into a collection and display a detailed report of records. Create a simple procedure in DB2 to test if empty strings are null in IBM DB2. Lab activities