Oracle PL/SQL/PL SQL/Table of Char

Check if next index value exists.

    
SQL>
SQL> DECLARE
  2    current VARCHAR2(9 CHAR);
  3    element INTEGER;
  4
  5    TYPE months_varray IS VARRAY(12) OF STRING(9 CHAR);
  6    TYPE calendar_table IS TABLE OF VARCHAR2(9 CHAR) INDEX BY VARCHAR2(9 CHAR);
  7
  8    month MONTHS_VARRAY := months_varray("January","February","March","April");
  9
 10    calendar CALENDAR_TABLE;
 11  BEGIN
 12    IF calendar.COUNT = 0 THEN
 13      FOR i IN month.FIRST..month.LAST LOOP
 14        calendar(month(i)) := TO_CHAR(i);
 15        DBMS_OUTPUT.PUT_LINE("Index ["||month(i)||"] is ["||i||"]");
 16      END LOOP;
 17
 18      FOR i IN 1..calendar.COUNT LOOP
 19        IF i = 1 THEN
 20          current := calendar.FIRST;
 21          element := calendar(current);
 22        ELSE
 23          IF calendar.NEXT(current) IS NOT NULL THEN
 24            current := calendar.NEXT(current);
 25            element := calendar(current);
 26          ELSE
 27            EXIT;
 28          END IF;
 29        END IF;
 30
 31        DBMS_OUTPUT.PUT_LINE("Index ["||current||"] is ["||element||"]");
 32      END LOOP;
 33    END IF;
 34  END;
 35  /
Index [January] is [1]
Index [February] is [2]
Index [March] is [3]
Index [April] is [4]
Index [April] is [4]
Index [February] is [2]
Index [January] is [1]
Index [March] is [3]
PL/SQL procedure successfully completed.

FIRST, LAST, NEXT, and PRIOR.

  
SQL>
SQL> set serveroutput on
SQL>
SQL> DECLARE
  2    TYPE CharTab IS TABLE OF CHAR(1);
  3    v_Characters CharTab :=
  4      CharTab("M", "a", "d", "a", "m", ",", " ", "I", """", "m", " ", "A", "d", "a", "m");
  5
  6    v_Index INTEGER;
  7  BEGIN
  8    v_Index := v_Characters.FIRST;
  9    WHILE v_Index <= v_Characters.LAST LOOP
 10      DBMS_OUTPUT.PUT(v_Characters(v_Index));
 11      v_Index := v_Characters.NEXT(v_Index);
 12    END LOOP;
 13    DBMS_OUTPUT.NEW_LINE;
 14
 15    v_Index := v_Characters.LAST;
 16    WHILE v_Index >= v_Characters.FIRST LOOP
 17      DBMS_OUTPUT.PUT(v_Characters(v_Index));
 18      v_Index := v_Characters.PRIOR(v_Index);
 19    END LOOP;
 20    DBMS_OUTPUT.NEW_LINE;
 21  END;
 22  /
Madam, I"m Adam
madA m"I ,madaM
PL/SQL procedure successfully completed.
SQL>
SQL>

Loop backwards over the table

  
SQL>
SQL> set serveroutput on
SQL>
SQL> DECLARE
  2    TYPE CharTab IS TABLE OF CHAR(1);
  3    v_Characters CharTab :=
  4      CharTab("M", "a", "d", "a", "m", ",", " ",
  5              "I", """", "m", " ", "A", "d", "a", "m");
  6
  7    v_Index INTEGER;
  8  BEGIN
  9    v_Index := v_Characters.LAST;
 10    WHILE v_Index >= v_Characters.FIRST LOOP
 11      DBMS_OUTPUT.PUT(v_Characters(v_Index));
 12      v_Index := v_Characters.PRIOR(v_Index);
 13    END LOOP;
 14
 15    DBMS_OUTPUT.NEW_LINE;
 16  END;
 17  /
madA m"I ,madaM
PL/SQL procedure successfully completed.
SQL>
SQL>

Print an indexed element from the array.

    
SQL> DECLARE
  2    current VARCHAR2(9 CHAR);
  3    element INTEGER;
  4
  5    TYPE months_varray IS VARRAY(12) OF STRING(9 CHAR);
  6    TYPE calendar_table IS TABLE OF VARCHAR2(9 CHAR) INDEX BY VARCHAR2(9 CHAR);
  7
  8    month MONTHS_VARRAY := months_varray("January","February","March","April","May","June","July","August","September","October","November","December");
  9
 10    calendar CALENDAR_TABLE;
 11  BEGIN
 12    IF calendar.COUNT = 0 THEN
 13      FOR i IN month.FIRST..month.LAST LOOP
 14        calendar(month(i)) := TO_CHAR(i);
 15        DBMS_OUTPUT.PUT_LINE("Index ["||month(i)||"] is ["||i||"]");
 16      END LOOP;
 17
 18      FOR i IN 1..calendar.COUNT LOOP
 19        IF i = 1 THEN
 20          current := calendar.FIRST;
 21          element := calendar(current);
 22        ELSE
 23          IF calendar.NEXT(current) IS NOT NULL THEN
 24            current := calendar.NEXT(current);
 25            element := calendar(current);
 26          ELSE
 27            EXIT;
 28          END IF;
 29        END IF;
 30
 31        DBMS_OUTPUT.PUT_LINE("Index ["||current||"] is ["||element||"]");
 32      END LOOP;
 33    END IF;
 34  END;
 35  /
Index [January] is [1]
Index [February] is [2]
Index [March] is [3]
Index [April] is [4]
Index [May] is [5]
Index [June] is [6]
Index [July] is [7]
Index [August] is [8]
Index [September] is [9]
Index [October] is [10]
Index [November] is [11]
Index [December] is [12]
Index [April] is [4]
Index [August] is [8]
Index [December] is [12]
Index [February] is [2]
Index [January] is [1]
Index [July] is [7]
Index [June] is [6]
Index [March] is [3]
Index [May] is [5]
Index [November] is [11]
Index [October] is [10]
Index [September] is [9]
PL/SQL procedure successfully completed.

Use table of char as an array

 

SQL>
SQL>
SQL> -- create demo table
SQL> create table Employee(
  2    ID                 VARCHAR2(4 BYTE)         NOT NULL,
  3    First_Name         VARCHAR2(10 BYTE),
  4    Last_Name          VARCHAR2(10 BYTE),
  5    Start_Date         DATE,
  6    End_Date           DATE,
  7    Salary             Number(8,2),
  8    City               VARCHAR2(10 BYTE),
  9    Description        VARCHAR2(15 BYTE)
 10  )
 11  /
Table created.
SQL>
SQL> -- prepare data
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2               values ("01","Jason",    "Martin",  to_date("19960725","YYYYMMDD"), to_date("20060725","YYYYMMDD"), 1234.56, "Toronto",  "Programmer")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values("02","Alison",   "Mathews", to_date("19760321","YYYYMMDD"), to_date("19860221","YYYYMMDD"), 6661.78, "Vancouver","Tester")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values("03","James",    "Smith",   to_date("19781212","YYYYMMDD"), to_date("19900315","YYYYMMDD"), 6544.78, "Vancouver","Tester")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values("04","Celia",    "Rice",    to_date("19821024","YYYYMMDD"), to_date("19990421","YYYYMMDD"), 2344.78, "Vancouver","Manager")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values("05","Robert",   "Black",   to_date("19840115","YYYYMMDD"), to_date("19980808","YYYYMMDD"), 2334.78, "Vancouver","Tester")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values("06","Linda",    "Green",   to_date("19870730","YYYYMMDD"), to_date("19960104","YYYYMMDD"), 4322.78,"New York",  "Tester")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values("07","David",    "Larry",   to_date("19901231","YYYYMMDD"), to_date("19980212","YYYYMMDD"), 7897.78,"New York",  "Manager")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values("08","James",    "Cat",     to_date("19960917","YYYYMMDD"), to_date("20020415","YYYYMMDD"), 1232.78,"Vancouver", "Tester")
  3  /
1 row created.
SQL>
SQL>
SQL>
SQL> -- display data in the table
SQL> select * from Employee
  2  /
ID   FIRST_NAME LAST_NAME  START_DAT END_DATE      SALARY CITY       DESCRIPTION
---- ---------- ---------- --------- --------- ---------- ---------- ---------------
01   Jason      Martin     25-JUL-96 25-JUL-06    1234.56 Toronto    Programmer
02   Alison     Mathews    21-MAR-76 21-FEB-86    6661.78 Vancouver  Tester
03   James      Smith      12-DEC-78 15-MAR-90    6544.78 Vancouver  Tester
04   Celia      Rice       24-OCT-82 21-APR-99    2344.78 Vancouver  Manager
05   Robert     Black      15-JAN-84 08-AUG-98    2334.78 Vancouver  Tester
06   Linda      Green      30-JUL-87 04-JAN-96    4322.78 New York   Tester
07   David      Larry      31-DEC-90 12-FEB-98    7897.78 New York   Manager
08   James      Cat        17-SEP-96 15-APR-02    1232.78 Vancouver  Tester
8 rows selected.
SQL>
SQL>
SQL>
SQL> -- Nested loops and labels
SQL>
SQL> DECLARE
  2    v_current_month INTEGER := TO_CHAR(SYSDATE,"MM");
  3    myNumber        INTEGER;
  4    TYPE char4list IS TABLE OF CHAR(4);
  5    month_list char4list := char4list("Jan","Feb","Mar","Apr","May","June","July","Aug","Sept","Oct","Nov","Dec");
  6    day_list char4list := char4list("Sun","Mon","Tues","Wed","Thur","Fri","Sat");
  7  BEGIN
  8
  9    FOR i IN 1..v_current_month LOOP
 10      DBMS_OUTPUT.PUT_LINE(month_list(i));
 11
 12      FOR j IN 1..7 LOOP
 13
 14        SELECT COUNT(*)
 15        INTO   myNumber
 16        FROM   employee
 17        WHERE  TO_CHAR(Start_Date,"fmYYYYMMD") =
 18            TO_CHAR(SYSDATE,"YYYY")||TO_CHAR(i)||TO_CHAR(j);
 19
 20        DBMS_OUTPUT.PUT_LINE(day_list(j)||" "||myNumber);
 21      END LOOP;
 22    END LOOP;
 23  END;
 24  /
Jan
Sun  0
Mon  0
Tues 0
Wed  0
Thur 0
Fri  0
Sat  0
Feb
Sun  0
Mon  0
Tues 0
Wed  0
Thur 0
Fri  0
Sat  0
Mar
Sun  0
Mon  0
Tues 0
Wed  0
Thur 0
Fri  0
Sat  0
Apr
Sun  0
Mon  0
Tues 0
Wed  0
Thur 0
Fri  0
Sat  0
May
Sun  0
Mon  0
Tues 0
Wed  0
Thur 0
Fri  0
Sat  0
June
Sun  0
Mon  0
Tues 0
Wed  0
Thur 0
Fri  0
Sat  0
July
Sun  0
Mon  0
Tues 0
Wed  0
Thur 0
Fri  0
Sat  0
Aug
Sun  0
Mon  0
Tues 0
Wed  0
Thur 0
Fri  0
Sat  0
Sept
Sun  0
Mon  0
Tues 0
Wed  0
Thur 0
Fri  0
Sat  0
PL/SQL procedure successfully completed.
SQL>
SQL>
SQL> -- clean the table
SQL> drop table Employee
  2  /
Table dropped.
SQL>
SQL>