Building examples of using SQL functions supported by Oracle
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Showing posts with label PL/SQL. Show all posts
Showing posts with label PL/SQL. Show all posts
SQL Functions (11gR2)
| Single-row F | Aggregate F | Analytic F |
| Object Reference F | Model F | OLAP F |
Single-row functions
- Numeric functions (26, 11gR2)
- ABS
- ACOS
- ASIN
- ATAN
- ATAN2
- BITAND
- CEIL
- COS
- COSH
- EXP
- FLOOR
- LN
- LOG
- MOD
- NANVL
- POWER
- REMAINDER
- ROUND (number)
- SIGN
- SIN
- SINH
- SQRT
- TAN
- TANH
- TRUNC (number)
- WIDTH BUCKET
- Character F returning character values (22, 11gR2)
- CHR
- CONCAT
- INITCAP
- LOWER
- LPAD
- LTRIM
- NCHR
- NLS_INITCAP
- NLS_LOWER
- NLS_UPPER
- NLSSORT
- REGEXP_REPLACE
- REGEXP_SUBSTR
- REPLACE
- RPAD
- RTRIM
- SOUNDEX
- SUBSTR
- TRANSLATE
- TREAT
- TRIM
- UPPER
- Character F returning number values (5, 11gR2)
- ASCII
- INSTR
- LENGTH
- REGEXP_COUNT
- REGEXP_INSTR
- NLS Character F (3, 11gR2)
- NLS_CHARSET_DECL_LEN
- NLS_CHARSET_ID
- NLS_CHARSET_NAME
- Datetime F (28, 11GR2)
- ADD_MONTHS
- CURRENT_DATE
- CURRENT_TIMESTAMP
- DBTIMEZONE
- EXTRACT (datetime)
- FROM_TZ
- LAST_DAY
- LOCALTIMESTAMP
- MONTHS_BETWEEN
- NEW_TIME
- NEXT_DAY
- NUMTODSINTERVAL
- NUMTOYMINTERVAL
- ORA_DST_AFFECTED
- ORA_DST_CONVERT
- ORA_DST_ERROR
- ROUND (date)
- SESSIONTIMEZONE
- SYS_EXTRACT_UTC
- SYSDATE
- SYSTIMESTAMP
- TO_CHAR (datetime)
- TO_DSINTERVAL
- TO_TIMESTAMP
- TO_TIMESTAMP_TZ
- TO_YMINTERVAL
- TRUNC (date)
- TZ_OFFSET
- General comparison F (2, 11gR2)
- GREATEST
- LEAST
- Conversion F (38, 11gR2)
- ASCIISTR
- BIN_TO_NUM
- CAST
- CHARTOROWID
- COMPOSE
- CONVERT
- DECOMPOSE
- HEXTORAW
- NUMTODSINTERVAL
- NUMTOYMINTERVAL
- RAWTOHEX
- RAWTONHEX
- ROWIDTOCAR
- ROWIDTONCHAR
- SCN_TO_TIMESTAMP
- TIMESTAMP_TO_SCN
- TO_BINARY_FLOAT
- TO_BINARY_DOUBLE
- TO_BLOB
- TO_CHAR (character)
- TO_CHAR (datetime)
- TO_CHAR (number)
- TO_CLOB
- TO_DATE
- TO_DSINTERVAL
- TO_LOB
- TO_MULTI_BYTE
- TO_NCHAR (character)
- TO_NCHAR (datetime)
- TO_NCHAR (number)
- TO_NCLOB
- TO_NUMBER
- TO_SINGLE_BYTE
- TO_TIMESTAMP
- TO_TIMESTAMP_TZ
- TO_YMINTERVAL
- TRANSLATE ... USING
- UNISTR
- Large Object F (3, 11gR2)
- BFILENAME
- EMPTY_BLOB
- EMPTY_CLOB
- Collection F (5, 11gR2)
- CARDINALITY
- COLLECT
- POWERMULTISET
- POWERMULTISET_BY_CARDINALITY
- SET
- Hierarchical F (1, 11gR2)
- SYS_CONNECT_BY_PATH
- Data Mining F (12, 11gR2)
- CLUSTER_ID
- CLUSTER_PROBABILITY
- CLUSTER_SET
- FEATURE_ID
- FEATURE_SET
- FEATURE_VALUE
- PREDICTION
- PREDICTION_BOUNDS
- PREDICTION_COST
- PREDICTION_DETAILS
- PREDICTION_PROBABILITY
- PREDICTION_SET
- XML F (26, 11gR2)
- Encoding and Decoding F (4, 11gR2)
- DECODE
- DUMP
- ORA_HASH
- VSIZE
- NULL-related F (6, 11gR2)
- COALESCE
- LNNVL
- NANVL
- NULLIF
- NVL
- NVL2
- Environment and Identifier F (6, 11gR2)
- SYS_CONTEXT
- SYS_GUID
- SYS_TYPEID
- UID
- USER
- USERENV
Aggregate Functions
(41, 11gR2)
Operate on groups of rows
Appear in SELECT, ORDER BY and HAVING
- AVG
- COLLECT
- CORR
- CORR *
- COUNT
- COVAR POP
- COVAR SAMP
- CUME DIST
- DENSE RANK
- FIRST
- GROUP_ID
- GROUPING
- GROUPING_ID
- LAST
- LISTAGG
- MAX
- MEDIAN
- MIN
- PERCENT_RANK
- PERCENTILE_CONT
- PERCENTILE_DISC
- RANK
- STATS_BINOMIAL_TEST
- STATS_CROSSTAB
- STATS_F_TEST
- STATS_KS_TEST
- STATS_MODE
- STATS_MW_TEST
- STATS_ONEW_WAY_ANOVA
- STATS_T_TEST *
- STATS_WSR_TEST
- STDDEV
- STDDEV_POP
- STDDEV_SAMP
- SUM
- SYS_XMLAGG
- VAR_POP
- VAR_SAMP
- VARIANCE
- XMLAGG
- Linear Regression Functions (9, 11gR2)
- REGR_SLOPE
- REGR_INTERCEPT
- REGR_COUNT
- REGR_R2
- REGR_AVGX
- REGR_AVGY
- REGR_SXX
- REGR_SYY
- REGR_SXY
Analytic Functions
(32, 11gR2)
Commonly used on Data Warehousing environments
Analytic functions are the last set of operations performed in a query, followed only by the ORDER BY clause
All joins and the WHERE, GROUP BY and HAVING clauses are completed prior to the analytic functions are processed
Good to compute cumulative, moving, centered, and reporting aggregates
- AVG *
- CORR *
- COUNT *
- COVAR_POP *
- COVAR_SAMP *
- CUME_DIST
- DENSE_RANK
- FIRST
- FIRST_VALUE *
- LAG
- LAST
- LAST_VALUE *
- LEAD
- LISTAGG
- MAX *
- MIN *
- NTH VALUE *
- NTILE
- PERCENT_RANK
- PERCENTILE_CONT
- PERCENTILE_DISC
- RANK
- RATIO_TO_REPORT
- ROW_NUMBER
- STDDEV *
- STDDEV_POP *
- STDDEV_SAMP *
- SUM *
- VAR_POP *
- VAR_SAMP *
- VARIANCE *
- Linear Regression Functions *
- AVG
(a) Reporting each employee's salary and the average salary of the employees within the same department.
SELECT first_name || ' ' || last_name AS emp_name,
department_id,
salary,
AVG (salary) OVER (PARTITION BY department_id) AS avg_dept_sal
FROM hr.employees;
EMP_NAME DEPARTMENT_ID SALARY AVG_DEPT_SAL
------------------ ------------- ------- ------------
Adam Fripp 50 8200 3475.55556
Alana Walsh 50 3100 3475.55556
Alberto Errazuriz 80 12000 8955.88235
Alexander Hunold 60 9000 5760
Alexander Khoo 30 3100 4150
Alexis Bull 50 4100 3475.55556
Allan McEwen 80 9000 8955.88235
Alyssa Hutton 80 8800 8955.88235
...
(a) Lists manager_id, employee's name, hire_date, salary and the average salary of all employees that have the same manager -- note the AVG is calculated over all rows within each partition. -- no windowing clause is present SELECT manager_id, last_name, hire_date, salary, AVG (salary) OVER (PARTITION BY manager_id) AS c_mavg FROM hr.employees ORDER BY manager_id, hire_date, salary; MANAGER_ID LAST_NAME HIRE_DATE SALARY C_MAVG ---------- ------------------------- --------- ---------- ---------- 100 De Haan 13-JAN-01 17000 11100 100 Raphaely 07-DEC-02 11000 11100 100 Kaufling 01-MAY-03 7900 11100 100 Hartstein 17-FEB-04 13000 11100 100 Weiss 18-JUL-04 8000 11100 ... 100 Zlotkey 29-JAN-08 10500 11100 101 Mavris 07-JUN-02 6500 8983.2 ... 101 Whalen 17-SEP-03 4400 8983.2 102 Hunold 03-JAN-06 9000 9000 103 Austin 25-JUN-05 4800 4950 ... (b)Lists employee salary and average salary of the employees reporting to the same manager who were hired in the range just before through just after the employee. -- note the query has -- 1. a partition clause (partition rows by manager) -- 2. a windowing clause (within each partition, AVG considers only the rows immediately preceding and following each employees' row). SELECT manager_id, last_name, hire_date, salary, AVG ( salary) OVER (PARTITION BY manager_id ORDER BY hire_date ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING) AS c_mavg FROM hr.employees ORDER BY manager_id, hire_date, salary; MANAGER_ID LAST_NAME HIRE_DATE SALARY C_MAVG ---------- ------------------------- --------- ---------- ---------- 100 De Haan 13-JAN-01 17000 14000 100 Raphaely 07-DEC-02 11000 11966.6667 ... 100 Cambrault 15-OCT-07 11000 7766.66667 100 Mourgos 16-NOV-07 5800 9100 100 Zlotkey 29-JAN-08 10500 8150 101 Mavris 07-JUN-02 6500 8250 101 Baer 07-JUN-02 10000 9502.66667 ... 101 Whalen 17-SEP-03 4400 8204 102 Hunold 03-JAN-06 9000 9000 103 Austin 25-JUN-05 4800 4800 ...
- FIRST_VALUE and LAST_VALUE
(a) For each employee, return employee salary and the name of the employee that works in the same department and has the lowest salary
SELECT department_id,
last_name,
salary,
FIRST_VALUE (last_name)
OVER (PARTITION BY department_id
ORDER BY salary ASC, hire_date
ROWS UNBOUNDED PRECEDING)
AS lowest_sal
FROM hr.employees
ORDER BY department_id, last_name;
DEPARTMENT_ID LAST_NAME SALARY LOWEST_SAL
------------- ------------------------- ---------- -------------------------
10 Whalen 4400 Whalen
20 Fay 6000 Fay
20 Hartstein 13000 Fay
30 Baida 2900 Colmenares
30 Colmenares 2500 Colmenares
30 Himuro 2600 Colmenares
30 Khoo 3100 Colmenares
30 Raphaely 11000 Colmenares
30 Tobias 2800 Colmenares
40 Mavris 6500 Mavris
...
80 Zlotkey 10500 Kumar
90 De Haan 17000 De Haan
90 King 24000 De Haan
90 Kochhar 17000 De Haan
100 Chen 8200 Popp
100 Faviet 9000 Popp
100 Greenberg 12008 Popp
100 Popp 6900 Popp
100 Sciarra 7700 Popp
100 Urman 7800 Popp
...
(b) For each employee of department 50, return salary of employees on the previous and following rows of the record set.
SELECT department_id,
last_name,
salary,
FIRST_VALUE (salary)
OVER (ORDER BY salary ASC
ROWS between 1 preceding and current row) as previous_sal,
LAST_VALUE (salary)
OVER (ORDER BY salary ASC
ROWS between current row and 1 following) as next_sal
FROM hr.employees
where department_id =50;
DEPARTMENT_ID LAST_NAME SALARY PREVIOUS_SAL NEXT_SAL
------------- ------------------------- ---------- ------------ ----------
50 Olson 2100 2100 2200
50 Philtanker 2200 2100 2200
50 Markle 2200 2200 2400
50 Gee 2400 2200 2400
50 Landry 2400 2400 2500
50 Patel 2500 2400 2500
50 Vargas 2500 2500 2500
50 Marlow 2500 2500 2500
50 Perkins 2500 2500 2500
50 Sullivan 2500 2500 2600
...
- RANK
SELECT department_id,
last_name,
salary,
commission_pct,
RANK ()
OVER (PARTITION BY department_id
ORDER BY salary DESC, commission_pct DESC)
"Rank"
FROM hr.employees
WHERE department_id = 80;
Object Reference Functions
- DEREF
- MAKE_REF
- REF
- REFTOHEX
- VALUE
Model Functions
- CV
- ITERATION_NUMBER
- PRESENTNNV
- PRESENTV
- PREVIOUS
OLAP Functions
- CUBE_TABLE
Data Cartridge Functions
- DATAOBJ_TO_PARTITION
User-Defined Functions
(6) Control Structures: CONTINUE statement
CONTINUE statement
- CONTINUE jumps out of the current LOOP interaction and STARTS THE NEXT ONE.
- Can be used on its own or as part of a CONTINUE WHEN
set serveroutput on
declare
l_number number := 0;
begin
for i in 1 .. 10 LOOP
-- code before CONTINUE: executed
dbms_output.put_line('Before Continue: Iteracao # '|| i ||'. MOD('||i||', 2) = '|| mod(i,2));
CONTINUE WHEN MOD(i,2) = 0;
-- If WHEN condition TRUE, code after continue: Jumped.
dbms_output.put_line('Iteracao # '|| i ||'. MOD('||i||', 2) = '|| mod(i,2));
l_number := l_number +1;
end loop;
dbms_output.put_line('CONTINUE WHEN:'|| l_number);
end;
Alternativelly:
set serveroutput on
declare
l_number number := 0;
begin
for i in 1 .. 10 LOOP
IF mod(i,2) = 0 THEN
CONTINUE;
END IF;
dbms_output.put_line('Iteracao # '|| i ||'. MOD('||i||', 2) = '|| mod(i,2));
l_number := l_number +1;
end loop;
- Before the CONTINUE statement, the same behavior could be implemented with IF, GOTO or EXCEPTIONS..:
set serveroutput on
declare
e_continue exception;
ln number :=0;
begin
for i in 1 .. 10 loop
begin
if mod(i,2) != 0 then
raise e_continue;
end if;
dbms_output.put_line('Iteracao # '|| i ||'. MOD('||i||', 2) = '|| mod(i,2));
ln := ln + 1;
exception
when e_continue then
null;
end;
end loop;
dbms_output.put_line('EXCEPTION: ' || ln);
set serveroutput on
declare
ln number :=0;
begin
ln := 0;
FOR i IN 1 .. 10 LOOP
IF MOD(i,2) != 0 THEN
dbms_output.put_line('Iteracao # '|| i ||'. MOD('||i||', 2) = '|| mod(i,2));
ln := ln + 1;
END IF;
END LOOP;
dbms_output.put_line('IF : ' || ln);
end;
set serveroutput on
declare
ln number :=0;
begin
ln := 0;
FOR i IN 1 .. 10 LOOP
IF MOD(i,2) = 0 THEN
GOTO label_continue;
END IF;
dbms_output.put_line('Iteracao # '|| i ||'. MOD('||i||', 2) = '|| mod(i,2));
ln := ln + 1;
<< label_continue >>
NULL;
END LOOP;
dbms_output.put_line('GOTO : ' || ln);
end;
Exception Handling: Nested Blocks
|  [ Oracle PL/SQL ] |
Case 1: Exception caught in the internal block
set serveroutput on
DECLARE -- outer block
e1 exception;
a integer;
BEGIN
a :=2;
declare -- inner block
e1 exception;
b integer;
begin
b := 2;
raise e1; -- exception e1 raised.
exception
when others then
dbms_output.put_line('error1 caught: inner block');
dbms_output.put_line(sqlerrm);
end;
a :=3;
raise e1; -- exception e1 raised.
EXCEPTION
when e1 then
dbms_output.put_line('error1 caught: outer block');
END;
/
anonymous block completed
error1 caught: inner block
User-Defined Exception
error1 caught: outer block
Case 2: Exception unhadled in the internal block is NOT caught in the external one
set serveroutput on
DECLARE -- outer block
e1 exception;
a integer;
BEGIN
a :=2;
declare -- inner block
e1 exception;
b integer;
begin
b := 2;
raise e1; -- exception e1 raised
exception
when no_data_found then
dbms_output.put_line('error1 caught: inner block');
dbms_output.put_line(sqlerrm);
end;
a :=3;
raise e1;
EXCEPTION
when e1 then
dbms_output.put_line('error1 caught: outer block');
END;
/
Error report:
ORA-06510: PL/SQL: unhandled user-defined exception
ORA-06512: at line 11
06510. 00000 - "PL/SQL: unhandled user-defined exception"
*Cause: A user-defined exception was raised by PL/SQL code, but
not handled.
*Action: Fix the problem causing the exception or write an exception
handler for this condition. Or you may need to contact your
application administrator or DBA.
Native Dynamic SQL x DBMS_SQL
With Oracle 11g:
- Native dynamic SQL and DBMS_SQL package now support statments larger than 32Kb.
- EXECUTE IMMEDIATE, OPEN-FOR and DBMS_SQL.PARSE accept SQL statements in the form of CLOBs.
- DBMS_SQL.TO_REFCURSOR converts a DBMS_SQL cursor ID into a REF CURSOR.
- DBMS_SQL.to_cursor_number converts a REF CURSOR into a DBMS_SQL cursor ID.
DBMS_SQL.TO_REFCURSOR: From Cursor ID => to REF CURSOR.set serveroutput on
declare
lcursor number; -- for DBMS_SQL Cursor ID
lreturn number; -- for DBMS_SQL Cursor ID
lref_cursor sys_refcursor; -- for REF CURSOR
type t_emptab is table of employees%rowtype;
lemp_tab t_emptab;
begin
lcursor := dbms_sql.open_cursor;
dbms_sql.parse(lcursor,
'Select * from employees',
DBMS_SQL.NATIVE);
lreturn := dbms_sql.execute(lcursor);
-- convert from dbms_sql Cursor ID to a REF CURSOR
lref_cursor := dbms_sql.to_refcursor(lcursor);
fetch lref_cursor bulk collect into lemp_tab;
dbms_output.put_line('Employee count: '||lemp_tab.count);
close lref_cursor;
end;
/
anonymous block completed
Elapsed: 00:00:00.050
Employee count: 107
DBMS_SQL.to_cursor_number: from REF CURSOR => to DBMS_SQL cursor ID.declare
lref_cursor sys_refcursor;
lcursor number;
lcount number := 0;
begin
OPEN lref_cursor FOR 'select * from employees';
-- convert from REF CURSOR to a dbms_sql Cursor ID
lcursor := dbms_sql.to_cursor_number(lref_cursor);
while dbms_sql.fetch_rows(lcursor) > 0 LOOP
lcount := lcount + 1;
end loop;
dbms_output.put_line('Employee count: '|| lcount);
dbms_sql.close_cursor(lcursor);
end;
/
anonymous block completed
Elapsed: 00:00:00.024
Employee count: 107
Native Dynamic SQL: OPEN FOR, FETCH and CLOSE
 | Native Dynamic SQL: OPEN FOR, FETCH and CLOSE |
Using dynamic SQL with OPEN FOR, FETCH and CLOSE:
set serveroutput on
declare
-- define a type cursor.
-- declare a variable of type cursor. This variable will
-- execute the dynamic SQL stmt later (OPEN, LOOP-FETCH, CLOSE).
type empcurtype is ref cursor;
v_emp_c empcurtype;
emp_rec employees%rowtype;
v_stmt_str varchar2(200);
v_e_job employees.job_id%type;
begin
-- dynamic SQL stmt. Note the placeholder (:j) for
-- a bind variable.
v_stmt_str := 'SELECT * FROM employees '||
'WHERE job_id = :j';
-- Open the cursor. List the bind variables
-- with the USING clause. Placeholders, in this
-- case (single SQL stmt), are associated
-- BY POSITION, and NOT by name.
OPEN v_emp_c FOR v_stmt_str USING 'IT_PROG';
LOOP
FETCH v_emp_c INTO emp_rec;
exit when v_emp_c%notfound;
dbms_output.put_line('Empid: '|| emp_rec.employee_id ||
'--'||emp_rec.first_name || ' ' || emp_rec.last_name );
END LOOP;
CLOSE v_emp_c;
end;
nonymous block completed
Empid: 103--Alexander Hunold
Empid: 104--Bruce Ernst
Empid: 105--David Austin
Empid: 106--Valli Pataballa
Empid: 107--Diana Lorentz
(cont..)
(19-20) PL/SQL Compiler
PL/SQL Compiler
- Several initialization parameters (compiler parameters) affect the compilation of PL/SQL units.
- The values at the time of compilation of the
PLSQL_CCFLAGS, PLSQL_CODE_TYPE, PLSQL_DEBUG, PLSQL_OPTIMIZE_LEVEL, PLSQL_WARNINGS, and NLS_LENGTH_SEMANTICSinitialization parameters are stored with the unit's metadata. ALL_PLSQL_OBJECT_SETTINGSview: Keeps information about the settings of these parameters.
PLSCOPE_SETTINGS | Controls compile-time collection, cross-reference, and storage of PL/SQL source text identifier data. PLSCOPE_SETTINGS = IDENTIFIERS:{ NONE | ALL } | PLSQL_CCFLAGS | Enables you to control conditional compilation of each PL/SQL unit independently. | PLQL_CODE_TYPE | Defines compilation mode for PL/SQL libary units.PLSQL_CODE_TYPE = { INTERPRETED | NATIVE } |
PLSQL_OPTIMIZE_LEVEL | The higher the setting of this parameter, the more effort the compiler makes to optimize PL/SQL library units.Range: {0,3} |
PLSQL_DEBUG | Specifies whether to compile PL/SQL units for debugging. Deprecated on 11g. To compile PL/SQL units for debugging, specify PLSQL_OPTIMIZE_LEVEL=1. |
PLSQL_NATIVE_LIBRARY_DIR PLSQL_NATIVE_LIBRARY_SUBDIR_COUNT | Related to Native Compilation.Deprecated on 11g. | PLSQL_WARNINGS | Enables/disables the reporting of warning messages by the PL/SQL compiler. Compile-time warning categories: [ SEVERE | PERFORMANCE | INFORMATIONAL ] |
NLS_LENGTH_SEMANTICS |
PL/SQL Optimizer
Prior to Oracle Database 10g Release 1 (10.1), the PL/SQL compiler translated your source text to system code without applying many changes to improve performance. Now, PL/SQL uses an optimizer that can rearrange code for better performance.
The optimizer is enabled by default. In rare cases, if the overhead of the optimizer makes compilation of very large applications too slow, you can lower the optimization by setting the compilation parameter PLSQL_OPTIMIZE_LEVEL=1 instead of its default value 2. In even rarer cases, PL/SQL might raise an exception earlier than expected or not at all. Setting PLSQL_OPTIMIZE_LEVEL=1 prevents the code from being rearranged.
 | On 10g R1 |
PLSQL_OPTIMIZE_LEVEL init parameter: Controls Global optimization of Pl/SQL Code. Default value is often good enough.Native compilation: fewer initialization parameters to set and less compiler configuration. Object code is stored in the database.
PLSQL_NATIVE_LIBRARY_DIR:Only parameter required.(Deprecated on 11g)PLSQL_CODE_TYPE:turn native compilation ON|OFF.PLSQL_COMPILER_FLAGS: Deprecated.$ORACLE_HOME/plsql/spnc_commandsfile contains the commands and options for compiling and linkingdbmsupgnv.sql: recompiles all the PL/SQL modules in a database as NATIVE.dbmsupgin.sql: recompiles all the PL/SQL modules in a database as INTERPRETED.
Compile-Time Warnings
- May be issued when you compile subprograms that produce ambiguous results or use inefficient constructs.
- Enable | Disable warnigns: Use
PLSQL_WARNINGSinit parameter orDBMS_WARNINGpackage.
| On 10g R2 |
- Conditional Compilation
- Enables selective inclusion of code depending on the values of the conditions evaluated during compilation. For example:
- You can determine which PL/SQL features in a PL/SQL application are used for specific database releases.
- Also useful when you want to execute debugging procedures in a development environment, but want to turn off the debugging routines in a production environment.
- Dynamic Wrap
DBMS_DDLwrap subprograms obfuscate (hide) dynamically generated PL/SQL code units.
--------------------------------------
| Pragmas |
Pragma Autonomous_transaction
- Marks a routine [(not-nested) anonymous block, subprogram, method (of ADT), Trigger] as autonomous; that is, independent of the main transaction
- Autonomous transactions do SQL operations and commit or rollback, without committing or rolling back the main transaction.
- When you enter the executable section of an autonomous routine, the main transaction suspends. When you exit the routine, the main transaction resumes.
- If you try to exit an active autonomous transaction without committing or rolling back, the database raises an exception.
- To exit normally, you must explicitly commit or roll back all autonomous transactions.
(1) Autonomous PL/SQL Block
-- create table emp as bellow:
SQL> create table emp
(name varchar2(20), jobid varchar2(10));
-- insert four initial rows and commit inserts.
SQL> insert into emp values('John', 'Accounting');
SQL> insert into emp values('Paul', 'Accounting');
SQL> insert into emp values('George', 'Ads');
SQL> insert into emp values('Ringo', 'Ads');
SQL> commit;
-- check the inserted rows.
SQL> select * from emp;
NAME JOBID
-------------------- ----------
John Accounting
Paul Accounting
George Ads
Ringo Ads
-- insert a 5th row. and do not commit.
-- Check the inserted row.
SQL> insert into emp values('Ghost', 'Ads');
1 row created.
SQL> select * from emp;
NAME JOBID
-------------------- ----------
John Accounting
Paul Accounting
George Ads
Ringo Ads
Ghost Ads
-- Now add the autonomous block.
SQL> set serveroutput on
SQL> declare
2 pragma autonomous_transaction;
3 numemp number;
4 begin
5 select count(*) into numemp from emp;
6 dbms_output.put_line('num emps before autonomous insert: ' || numemp);
7 insert into emp values('Autonomous', 'New');
8 dbms_output.put_line('Inserted: Autonomous');
9 select count(*) into numemp from emp;
10 dbms_output.put_line('num emps after autonomous insert: ' || numemp);
11 commit;
12 end;
13 /
num emps before autonomous insert: 4
Inserted: Autonomous
num emps after autonomous insert: 5
PL/SQL procedure successfully completed.
-- Now outside the autonomous block, check the existing
-- rows and rollback the insertion of "Ghost"
SQL> select * from emp;
NAME JOBID
-------------------- ----------
John Accounting
Paul Accounting
George Ads
Ringo Ads
Ghost Ads
Autonomous New
SQL> rollback;
Rollback complete.
-- Check that the row for "Ghost" was rolled back, but the
-- value inserted in the autonomous transaction remained.
SQL> select * from emp;
NAME JOBID
-------------------- ----------
John Accounting
Paul Accounting
George Ads
Ringo Ads
Autonomous New
SQL>
(2) Autonomous standalone procedure
In the example above, the anonymous block could be rewritten as an autonomous procedure
as below:
CREATE OR REPLACE PROCEDURE ins_emp
AS
pragma autonomous_transaction;
numemp number;
BEGIN
select count(*) into numemp from emp;
dbms_output.put_line('num emps before autonomous insert: ' || numemp);
insert into emp values('Autonomous', 'New');
dbms_output.put_line('Inserted: Autonomous');
select count(*) into numemp from emp;
dbms_output.put_line('num emps after autonomous insert: ' || numemp);
commit;
END ins_emp;
(3) Autonomous Triggers
A trigger must be autonomous to run TCL or DDL statements.
To run DDL statements, the trigger must use native dynamic SQL.
Associates a user-defined exception name with an error code.
Can appear only in the same declarative part as its associated exception, anywhere after the exception declaration.
DECLARE
past_due EXCEPTION; -- declare exception
PRAGMA EXCEPTION_INIT (past_due, -20000); -- assign error code to exception
BEGIN
...
Check herefor an example.Pragma Inline (check here)
- Specifies whether a subprogram invocation (or statement) is to be inlined.
- Inlining replaces a subprogram invocation with a copy of the invoked subprogram (if the invoked and invoking subprograms are in the same program unit).
- To allow subprogram inlining:
PLSQL_OPTIMIZE_LEVELcompilation parameter := [2 (default) | 3 ] - If a particular subprogram is inlined, performance almost always improves. However, because the compiler inlines subprograms early in the optimization process, it is possible for subprogram inlining to preclude later, more powerful optimizations.
Pragma Restrict_References
- Asserts that a user-defined subprogram does not read or write database tables or package variables.
- Can appear only in a package specification or ADT specification. Typically, this pragma is specified for functions.
- Subprograms that read or write database tables or package variables are difficult to optimize, because any invocation of the subprogram might produce different results or encounter errors. .
| Package... | memory usage |
|---|---|
...IS NOT SERIALY_REUSABLE | Package state stored in the user global area (UGA) for each user. The amount of UGA memory needed increases linearly with the number of users. Package state can persist for the life of a session, locking UGA memory. |
...IS SERIALY_REUSABLE | Package state stored in a work area in a small pool in the system global area (SGA). Package state persists only for the life of a server call, after which the work area returns to the pool. If a subsequent server call references the package, then Oracle Database reuses an instantiation from the pool. Reusing an instantiation re-initializes it; therefore, changes made to the package state in previous server calls are invisible. |
CREATE OR REPLACE PACKAGE pkg IS PRAGMA SERIALLY_REUSABLE; n number:= 5; END; / CREATE OR REPLACE PACKAGE BODY pkg IS PRAGMA SERIALLY_REUSABLE; BEGIN n := 5; END; /
- Allow you to better manage memory for scalability.
- Specifies that the package state is needed for only one call to the server, after which the storage for the package variables can be reused, reducing the memory overhead for long-running sessions.
- Appropriate for packages that declare large temporary work areas that are used once in the same session.
--------------------------
| Conditional compilation |
- The Conditional compilation (CC) feature and related PL/SQL packages are available for the 10g Release 1 (10.1.0.4) and later.
- CC allows constructs — with formally defined syntax and semantics — to be used to mark up text so that a preprocessor can deterministically derive the text that will be submitted to the compiler proper.
- CC uses (a) selection directives($) (similar to IF stmt), (b) inquiry directives($$), and (c) error directives.
- CC uses preprocessor control tokens($) to mark code that is processed before the PL/SQL unit is compiled:
$IF, $THEN, $ELSE, $ELSIF, $ERROR - Oracle’s Applications Division provided the use case that motivated the introduction of PL/SQL conditional compilation. They wanted their code to be able to span different releases of Oracle Database, using the latest features in the latest release and using a fallback in earlier releases.(see more here)
Uses of Conditional Compilation (CC) {see detailed discussion in this white paper}
- Allowing self-tracing code to be turned on during development and to be turned off when the code goes live.
- Allowing alternative code fragments, each appropriate for the peculiarities of a particular operating system and inappropriate or illegal for other operating systems, to coexist in the same source text so the correct fragment can be selected for compilation according to the circumstances.
- Newer Oracle releases introduce new features with new syntax and programs that take advantage of these are illegal in earlier releases. PL/SQL conditional compilation supports this use in an elegant and powerful way.
- A developer often realizes that more than one approach to the design of a subprogram will result in its correct behavior; sometimes the alternative approaches result in source code versions which are textually largely the same but which differ critically in small areas distributed fairly evenly thought the source. PL/SQL conditional compilation allows all the approaches to be coded in a single source text — while they are being evaluated — and thereby eliminates the risk of carelessly introduced unintended differences.
- Modular delivery of extra functionality can be implemented by optional PL/SQL compilation units which are installed according to what the customer has licensed. PL/SQL’s dependency model prevents the core part of the application referring statically to optional components that are not installed. However, the core part of the application should not need reinstallation in order to accommodate the installation of a new optional component. This has forced the use of dynamic invocation — which has some drawbacks. Conditional compilation allows a new approach.
Using selection directives
($IF, $ELSE) and error directives ($ERROR)set serveroutput on
begin
$IF dbms_db_version.ver_le_10_1 $THEN
$ERROR 'unsupported database release' $END
$ELSE
dbms_output.put_line (
'release ' || dbms_db_version.version || '.' ||
dbms_db_version.release || ' is supported.'
);
-- since its a newer release, use a new commit syntax
-- supported in 10.2
commit write immediate nowait;
$END
end;
/
anonymous block completed
release 11.2 is supported.
The package
DBMS_DB_VERSION provide static constants:- dbms_db_version.version
- dbms_db_version.release
- dbms_db_version.ver_le_v
- dbms_db_version.ver_le_v_r
Inquiry directives($$)
$$PLSQL_LINE:the number of the source line on which the directive appears in the current PL/SQL unit.$$PLSQL_UNIT:the name of the current PL/SQL unit.
- You can assign values to inquiry directives with the
PLSQL_CCFLAGScompilation parameter ALTER SESSION set PLSQL_CCFLAGS = 'flag:True, val:5'$$plsql_compilation_parameter: a PL/SQL compilation parameter
Displaying Values of PL/SQL Compilation Parameters
BEGIN
DBMS_OUTPUT.PUT_LINE('$$PLSCOPE_SETTINGS = ' || $$PLSCOPE_SETTINGS);
DBMS_OUTPUT.PUT_LINE('$$PLSQL_CCFLAGS = ' || $$PLSQL_CCFLAGS);
DBMS_OUTPUT.PUT_LINE('$$PLSQL_CODE_TYPE = ' || $$PLSQL_CODE_TYPE);
DBMS_OUTPUT.PUT_LINE('$$PLSQL_OPTIMIZE_LEVEL = ' || $$PLSQL_OPTIMIZE_LEVEL);
DBMS_OUTPUT.PUT_LINE('$$PLSQL_WARNINGS = ' || $$PLSQL_WARNINGS);
DBMS_OUTPUT.PUT_LINE('$$NLS_LENGTH_SEMANTICS = ' || $$NLS_LENGTH_SEMANTICS);
END;
/
anonymous block completed
$$PLSCOPE_SETTINGS =
$$PLSQL_CCFLAGS =
$$PLSQL_CODE_TYPE = INTERPRETED
$$PLSQL_OPTIMIZE_LEVEL = 0
$$PLSQL_WARNINGS = DISABLE:ALL
$$NLS_LENGTH_SEMANTICS = BYTE
 | Using inquiry directives (example extracted from here) |
-- USE PACKAGE SPEC and BODY to define and declare a USER-DEFINED subtype.
-- Package specification: Use selection directive ($IF) to test for the
-- version of the database.
-- If version < 10g, define subtype as NUMBER.
-- If version >= 10g, define subtype as BINARY_DOUBLE
create or replace package my_pkg AS
subtype my_real IS
$IF dbms_db_version.version < 10 $THEN
number;
$ELSE
binary_double;
$END
my_pi my_real;
my_e my_real;
end my_pkg;
/
-- Package body: test for db version. Assign values
-- for the subtype variable accordingly.
create or replace package body my_pkg AS
begin
$IF dbms_db_version.version < 10 $THEN
my_pi := 3.14159265358979323846264338327950288420;
my_e := 2.71828182845904523536028747135266249775;
$ELSE
my_pi := 3.14159265358979323846264338327950288420d;
my_e := 2.71828182845904523536028747135266249775d;
$END
END my_pkg;
/
-- Use the subtype defined in the package on a standalone procedure.
-- Uses inquiry directive($$my_debug) to decide whether or not
-- to run some code. If $$my_debug = TRUE, run the debug code that
-- check for the datatype of the subtype my_real.
create or replace procedure circle_area (radius my_pkg.my_real) IS
my_area my_pkg.my_real;
my_data_type varchar2(30);
begin
my_area := my_pkg.my_pi * (radius**2);
dbms_output.put_line
('Radius: '|| to_char(radius) || ' Area: '|| to_char(my_area));
$IF $$my_debug $THEN
select data_type into my_data_type
from user_arguments
where object_name = 'CIRCLE_AREA'
and ARGUMENT_NAME = 'RADIUS';
dbms_output.put_line
('Data type of the RADIUS argument is: '|| my_data_type);
$END
end circle_area;
/
-- Run procedure circle_area
(1) Set $$my_debug: FALSE
SQL> alter session set plsql_ccflags = 'my_debug:FALSE';
Session SET altered.
SQL> set serveroutput on
SQL> exec circle_area(2);
Radius: 2.0E+000 Area: 1.2566370614359172E+001
PL/SQL procedure successfully completed.
(1) Set $$my_debug: TRUE
SQL> alter session set plsql_ccflags = 'my_debug:TRUE';
Session SET altered.
-- You need to recompile the procedure circle_area so it can
-- see the change in the session
SQL> alter procedure circle_area compile;
Procedure altered.
SQL> set serveroutput on
SQL> exec circle_area(2);
Radius: 2.0E+000 Area: 1.2566370614359172E+001
Data type of the RADIUS argument is: BINARY_DOUBLE
PL/SQL procedure successfully completed.
Using
DBMS_PREPROCESSOR to print source text- You can use the dbms_preprocessor package to print the source text executed after
the conditional compilation directives were all processed. - For the procedure circle_area above, you can retrieve the source code processed when the
debug directive ($$my_debug) is set to TRUE. - Subprograms
DBMS_PREPROCESSOR.PRINT_POST_PROCESSED_SOURCEDBMS_PREPROCESSOR.GET_POST_PROCESSED_SOURCE(overloaded (3))
SQL> call dbms_preprocessor.print_post_processed_source
2 ('PROCEDURE', 'DEV2', 'CIRCLE_AREA');
procedure circle_area (radius my_pkg.my_real) IS
my_area my_pkg.my_real;
my_data_type varchar2(30);
begin
my_area := my_pkg.my_pi * (radius**2);
dbms_output.put_line
('Radius: '|| to_char(radius) || ' Area: '|| to_char(my_area));
select data_type into my_data_type
from user_arguments
where object_name = 'CIRCLE_AREA'
and ARGUMENT_NAME = 'RADIUS';
dbms_output.put_line
('Data type of the RADIUS argument is: '|| my_data_type);
end circle_area;
Call completed.
CC Restrictions:
- You cannot have a CC directive within a
CREATE TYPEstatement. (Why? Attributes of a TYPE will determine the physical structure of dependent tables.) - Package Spec, Package body, type body, procedure/function w/o parameters: first conditional compilation directive cannot appear before the keyword IS or AS.
- subprogram with at least one formal parameter: the first conditional compilation directive cannot appear before the left parenthesis that follows the subprogram name.
- Trigger or an anonymous block, the first conditional compilation directive cannot appear before the keyword DECLARE or BEGIN, whichever comes first.
| On 11g R2: Compiling PL/SQL Units for Native Execution |
- PL/SQL units can be compiled into native code (processor-dependent system code), which is stored in the SYSTEM tablespace.
- Any PL/SQL unit of any type can be natively compiled, including Oracle supplied ones.
- Natively compiled program units work in all server environments.
- Greatest performance gains: for computation-intensive procedural operations. (i.e. Data warehouse and applications with extensive server-side transformations of data for display).
- Least performance gains: for PL/SQL subprograms that spend most of their time running SQL.
- The
PLSQL_CODE_TYPEcompilation parameter determines whether PL/SQL code is natively compiled or interpreted. ALTER PROCEDURE my_proc COMPILE PLSQL_CODE_TYPE=NATIVE REUSE SETTINGS;- Run this query to determine how many objects are compiled NATIVE and INTERPRETED:
SELECT TYPE, PLSQL_CODE_TYPE, COUNT(*) FROM DBA_PLSQL_OBJECT_SETTINGS WHERE PLSQL_CODE_TYPE IS NOT NULL GROUP BY TYPE, PLSQL_CODE_TYPE ORDER BY TYPE, PLSQL_CODE_TYPE;
| Obfuscation and wrapping |
(12) Packages
About Packages:
- Schema object that groups logically related PL/SQL types, variables, constants, subprograms, cursors, and exceptions.
Package specification:
- Declares the public items that can be referenced from outside the package. Works as an (API).
- If the public items include cursors or subprograms, then the package must also have a body.
- The scope of a public item is the schema of the package. A public item is visible everywhere in the schema.
- AUTHID clause determines:
- whether subprograms and cursors in the package run with the definer (the default) or invoker privileges.
- whether unqualified references to schema objects are resolved in the schema of the definer or invoker.
Package Body:
- Package body is optional, unless package specification declares cursors or subprograms.
- The package body and package specification must be in the same schema.
- Can also declare and define private items that cannot be referenced from outside the package
- Can have an initialization part, whose statements initialize variables and do other one-time setup steps.
- In either the package specification or package body, you can map a package subprogram to an external Java or C subprogram
- For this, you use a call specification, which maps the external subprogram name, parameter types, and return type to their SQL counterparts.
Why use packages?
- Modularity:
- encapsulate logically related types, variables, constants, subprograms, cursors, and exceptions.
- You can modify package objects without recompiling dependent schema objects
- Let you OVERLOAD subprograms.
- Easier Application design
- Can contain global variables and cursors that are available to all subprograms in the package.
- Packages increase your namespace -- "you get
pkg.procinstead of 5,000 little procedures with meaningless names, you can have 500 packages with good module names, each with 10 procedures that have meaningful names (that might be the same as the name of a procedure in another package). (ask tom) - good coding practices
- Allow many small procedures instead a few large ones.
- Packages maintain a state
- Packages allow you to create types
- Information Hiding
- You may have 20 procedures in the body, but choose to make only 10 of them public in the specificaiton
- Added functionality: Package public variables and cursors can persist for the life of a session.
- Better performance:
After first time you invoke a package subprogram, Oracle Database loads the package as needed into memory. Packages ARE NOT entirely loaded immediately. - Better Security control and privilege management: more efficient grant privileges
What are appropriate public items?
- types, variables, constants, subprograms, cursors, and exceptions
- Associative arrays type of standalone subprogram parameters: Since you cannot declare an AA type at schema level.
- variables that must remain available between subprogram invocations in the same session.
- subprograms that read and write public variables.
- subprograms that invoke each other.
- overloaded subprograms
Note: You cannot reference remote package public variables, even indirectly.
 | Package instantiation and initialization: |
- When a session references a package item, Oracle Database instantiates the package for that session.
- Every session that references a package has its own instantiation of that package.
- Initialization includes whichever of the following are applicable:
- Assigning initial values to public constants
- Assigning initial values to public variables whose declarations specify them.
- Executing the initialization part of the package body
| Package State |
- Package state: the values of the variables, constants, and cursors that a package declares (in either its specification or body)
- If a PL/SQL package declares at least one variable, constant, or cursor, then the package is stateful;
- otherwise, it is stateless.
- Each session that references a package item has its own instantiation of that package.
- If the package is stateful, the instantiation includes its state.
- The package state persists for the life of a session, except in these situations:
- package is SERIALLY_REUSABLE
- package body recompiled
| SERIALLY_REUSABLE |
- The package state is stored in a work area in a small pool in the system global area (SGA).
- If a package is NOT SERIALLY_REUSABLE:
- its package state is stored in the user global area (UGA) for each user.
- Limit scalability: the amount of UGA memory needed increases linearly with the number of users.
- Potential high usage of memory: The package state can persist for the life of a session, locking UGA memory until the session ends.
- For a SERIALLY_REUSABLE package, the work unit is a server call.
- You must use its public variables only within the work unit.
- If you depend on the value of a public variable that was set in a previous work unit, your program can fail. PL/SQL cannot check for such cases.
 | About Packages: Initialization and variables. |
(1) The package body can have an executable section.
(2) This section is executed when the first reference to a package object
is made. In the example, when you print the value of variable 'value'
in an anonymous block.
(3) The package body can have an initialization part, whose statements
initialize public variables and do other one-time setup steps.
The initialization part runs only the first time the package is referenced.
The initialization part can include an exception handler.
-- (1) create package ..
create or replace package my_pack
as
value number := 100;
const constant number := 999;
procedure update_value (pval number);
end my_pack;
/
-- (2) .. and package body
create or replace package body my_pack
as
procedure update_value (pval number)
is
begin
my_pack.value := pval;
dbms_output.put_line('my_pack.value updated to: '|| my_pack.value);
dbms_output.put_line('my_pack.const: '|| my_pack.const);
end;
begin --- executable section of package. Runs once.
dbms_output.put_line('initial value of my_pack.value: '|| my_pack.value);
dbms_output.put_line('initial value of value: '|| value);
dbms_output.put_line('initial value of my_pack.const: '|| my_pack.const);
my_pack.value := 300;
dbms_output.put_line('New value of my_pack.value: '|| my_pack.value);
end my_pack;
/
--(3) The initialization code is executed after the first call to a package object..
set serveroutput on
declare
x number;
begin
x := my_pack.const; -- First call to a package object.
dbms_output.put_line('x is: '|| x);
x := my_pack.value;
dbms_output.put_line('x is: '|| x);
end;
/
anonymous block completed
initial value of my_pack.value: 100
initial value of value: 100
initial value of my_pack.const: 999
New value of my_pack.value: 300
x is: 999
x is: 300
--(4) Run the anonymous block again. The executable section in the package body IS NOT executed again.
anonymous block completed
x is: 999
x is: 300
--(5) If you recompile the package, the initialization code is executed again, in the first call to a package object.
SQL> alter package my_pack compile;
package MY_PACK altered.
set serveroutput on
declare
x number;
begin
x := my_pack.const;
dbms_output.put_line('x is: '|| x);
x := my_pack.value;
dbms_output.put_line('x is: '|| x);
end;
/
anonymous block completed
initial value of my_pack.value: 100
initial value of value: 100
initial value of my_pack.const: 999
New value of my_pack.value: 300
x is: 999
x is: 300
| One-time Procedures and Global Package variables |
USER A Executes:
create or replace package set_global_commission
as
serv_commission number(4,2);
end;
/
create or replace package body set_global_commission
as
vtemp number(4,2);
begin
select avg(commission_pct) into serv_commission
from usera.employees;
vtemp := serv_commission;
set_global_commission.serv_commission := set_global_commission.serv_commission * 2;
dbms_output.put_line('Original: '|| to_char(vtemp) ||
' Current: ' || to_char(set_global_commission.serv_commission));
end set_global_commission;
/
Package body created.
-- Now initializing the package state:
set serveroutput on
begin
dbms_output.put_line('Service commission is: '|| set_global_commission.serv_commission);
set_global_commission.serv_commission := set_global_commission.serv_commission * 5.37;
dbms_output.put_line('New value for User A session is: '|| set_global_commission.serv_commission);
end;
/
anonymous block completed
Original: .22 Current: .44
Service commission is: .44
New value for User A session is: 2.36
Question: Now Can User B access the variable value?
Answer: User B CANNOT access the value held in the session by User A. User B can ONLY see the value for the variable set within his own session:
As USER B:
set serveroutput on
begin
dbms_output.put_line('Service commission is: '|| usera.set_global_commission.serv_commission);
end;
/
Error report:
ORA-06550: line 2, column 51:
PLS-00201: identifier 'USERA.SET_GLOBAL_COMMISSION' must be declared
ORA-06550: line 2, column 2:
| Accessing Package variables: restriction |
- If a subprogram has as formal parameter a variable defined on package specification,
calls to the subprogram need to reference the package variable definition when defining
the ACTUAL parameter that will be used.
-- Example:
- (1) package my_rec defines a RECORD type used as formal parameter type in a procedure proc1.
- (2) When calling proc1 from OUTSIDE the package, the ACTUAL parameter needs to be defined using the
record type defined in the package.
create or replace package my_rec
is
type t_emprec is record (
empid employees.employee_id%type,
ln employees.last_name%type,
fs employees.first_name%type);
procedure proc1 (p_empid in number, p_emp_info OUT t_emprec);
end my_rec;
/
create or replace package body my_rec
is
procedure proc1 (p_empid in number, p_emp_info OUT t_emprec)
is
begin
select employee_id, last_name, first_name
into p_emp_info
from employees
where employee_id = p_empid;
end proc1;
end my_rec;
-- Case 1: Success
set serveroutput on
declare
emprec my_rec.t_emprec;
begin
my_rec.proc1(100, emprec);
dbms_output.put('Id => '|| emprec.empid || ' ');
dbms_output.put_line('name => '|| emprec.fs || ' '|| emprec.ln);
end;
/
anonymous block completed
Id => 100 name => Steven King
-- Case 2: Failure, even though the data type of the actual parameter RECORD was
formed by the same components used in the definition of the FORMAL parameter.
set serveroutput on
declare
type t_emprec2 is record (
empid employees.employee_id%type,
ln employees.last_name%type,
fs employees.first_name%type);
emprec2 t_emprec2;
begin
my_rec.proc1(100, emprec2);
dbms_output.put('Id => '|| emprec2.empid || ' ');
dbms_output.put_line('name => '|| emprec2.fs || ' '|| emprec2.ln);
end;
/
Error report:
ORA-06550: line 9, column 3:
PLS-00306: wrong number or types of arguments in call to 'PROC1'
ORA-06550: line 9, column 3:
| Information about Packages in the Data Dictionary |
SQL> SELECT object_name, object_type, last_ddl_time, timestamp, status
FROM user_objects
WHERE object_type IN ('PACKAGE','PACKAGE BODY');
/
OBJECT_NAME OBJECT_TYPE LAST_DDL_ TIMESTAMP STATUS
------------------------- ------------------ ---------- ------------------- -------
DEPARTMENT_PKG PACKAGE 03-OCT-11 2011-10-03:14:22:52 VALID
DEPARTMENT_PKG PACKAGE BODY 03-OCT-11 2011-10-03:14:23:45 VALID
MESSAGE_API PACKAGE 19-SEP-11 2011-09-19:01:15:22 VALID
MESSAGE_API PACKAGE BODY 19-SEP-11 2011-09-19:01:18:22 VALID
MY_PACK PACKAGE 19-SEP-11 2011-09-19:13:11:00 VALID
MY_PACK PACKAGE BODY 19-SEP-11 2011-09-19:13:22:10 VALID
SET_EMPNO_CTX_PKG PACKAGE BODY 27-SEP-11 2011-09-27:09:56:41 INVALID
SET_GLOBAL_COMMISSION PACKAGE 23-SEP-11 2011-09-23:10:26:32 VALID
SET_GLOBAL_COMMISSION PACKAGE BODY 23-SEP-11 2011-09-23:10:37:00 VALID
SQL> DESCRIBE my_pack
PROCEDURE Argument Name Type IN/OUT Default
------------ ------------- ------ ------ -------
UPDATE_VALUE PVAL NUMBER IN unknown
| Dependencies between subprograms |
- The view
all_dependencies; user_dependencies; dba_dependencies;let you examine dependencies between stored programs. - Invalid package body does not invalidate procedures that reference (and thus depend upon) the package specification.
- This is because the package specification is the schema-level component.
- In this case, since the subprograms don't see the invalid package body, a run-time error will be raised if the
procedure makes a call to an object that needs to execute within the invalid package body.
SQL>SELECT name, type, referenced_name, referenced_type, dependency_type
FROM user_dependencies
ORDER BY name;
NAME TYPE REFERENCED_NAME REFERENCED DEPE
-------------------- ------------ ------------------------------ ---------- ----
DEPARTMENT_PKG PACKAGE BODY STANDARD PACKAGE HARD
DEPARTMENT_PKG PACKAGE STANDARD PACKAGE HARD
DEPARTMENT_PKG PACKAGE EMPLOYEES TABLE HARD
DEPARTMENT_PKG PACKAGE BODY EMPLOYEES TABLE HARD
DEPARTMENT_PKG PACKAGE BODY DEPARTMENT_PKG PACKAGE HARD
DEPARTMENT_PKG PACKAGE DEPARTMENTS TABLE HARD
DEPARTMENT_PKG PACKAGE BODY DEPARTMENTS TABLE HARD
EMP_NO_SAL VIEW EMPLOYEES TABLE HARD
FIBONACCI FUNCTION STANDARD PACKAGE HARD
GET_BONUS PROCEDURE STANDARD PACKAGE HARD
GET_BONUS PROCEDURE BONUS TABLE HARD
GET_BONUS PROCEDURE DBMS_OUTPUT SYNONYM HARD
GET_BONUS PROCEDURE SYS_STUB_FOR_PURITY_ANALYSIS PACKAGE HARD
MESSAGE_API PACKAGE BODY DBMS_PIPE SYNONYM HARD
MESSAGE_API PACKAGE BODY EMPLOYEES TABLE HARD
MESSAGE_API PACKAGE BODY STANDARD PACKAGE HARD
MESSAGE_API PACKAGE BODY DBMS_STANDARD PACKAGE HARD
MESSAGE_API PACKAGE BODY MESSAGE_API PACKAGE HARD
MESSAGE_API PACKAGE BODY DBMS_OUTPUT SYNONYM HARD
MESSAGE_API PACKAGE EMPLOYEES TABLE HARD
MY_PACK PACKAGE BODY MY_PACK PACKAGE HARD
MY_PACK PACKAGE BODY DBMS_OUTPUT SYNONYM HARD
MY_PACK PACKAGE BODY STANDARD PACKAGE HARD
MY_PACK PACKAGE STANDARD PACKAGE HARD
| Checking dependency and status: |
create or replace procedure pget_salary
(p_empid in employees.employee_id%type)
as
vsal employees.salary%type;
begin
select salary into vsal
from employees
where employee_id = p_empid;
dbms_output.put_line('Salary of empid: '|| p_empid || ' is '|| vsal);
end pget_salary;
/
create or replace package my_pack as
procedure p1 (p_empid employees.employee_id%type);
end;
/
create or replace package body my_pack as
procedure p1 (p_empid employees.employee_id%type)
is
begin
dbms_output.put_line('calling pget_salary for employee '|| p_empid);
pget_salary(p_empid);
end p1;
end my_pack;
/
Now check user_objects, user_dependencies, user_arguments
-- (1) Check object dependencies on USER_DEPENDENCIES
select name, type, referenced_name, referenced_type, dependency_type
from user_dependencies
where name in ('MY_PACK', 'PGET_SALARY')
order by name, type;
NAME TYPE REFERENCED_NAME REFERENCED_T DEPENDENCY
---------------- ------------ ---------------------------- ------------ ----------
MY_PACK PACKAGE EMPLOYEES TABLE HARD
MY_PACK PACKAGE BODY STANDARD PACKAGE HARD
MY_PACK PACKAGE BODY DBMS_OUTPUT SYNONYM HARD
MY_PACK PACKAGE BODY MY_PACK PACKAGE HARD
MY_PACK PACKAGE BODY EMPLOYEES TABLE HARD
MY_PACK PACKAGE BODY PGET_SALARY PROCEDURE HARD
PGET_SALARY PROCEDURE EMPLOYEES TABLE HARD
PGET_SALARY PROCEDURE STANDARD PACKAGE HARD
PGET_SALARY PROCEDURE DBMS_OUTPUT SYNONYM HARD
PGET_SALARY PROCEDURE SYS_STUB_FOR_PURITY_ANALYSIS PACKAGE HARD
-- (2) Check LAST_DDL_TIME and validity status on USER_OBJECTS
select object_name, object_type,
to_char(last_ddl_time, 'DD-MON-YY:HH:MI:SS') LAST_DDL_TIME,
timestamp, status
from user_objects
where object_name in ('MY_PACK', 'PGET_SALARY');
/
OBJECT_NAME OBJECT_TYPE LAST_DDL_TIME TIMESTAMP STATUS
------------- -------------- ------------------ ------------------- -------
MY_PACK PACKAGE 04-OCT-11:11:35:09 2011-10-04:11:35:09 VALID
MY_PACK PACKAGE BODY 04-OCT-11:11:35:14 2011-10-04:11:35:14 VALID
PGET_SALARY PROCEDURE 04-OCT-11:12:06:52 2011-10-04:11:31:12 VALID
set serveroutput on
begin
my_pack.p1(100);
end;
/
anonymous block completed
calling pget_salary for employee 100
Salary of empid: 100 is 7500
alter package my_pack compile;
OBJECT_NAME OBJECT_TYPE LAST_DDL_TIME TIMESTAMP STATUS
------------- -------------- ------------------ ------------------- -------
MY_PACK PACKAGE 04-OCT-11:12:20:21 2011-10-04:11:35:09 VALID
MY_PACK PACKAGE BODY 04-OCT-11:12:20:21 2011-10-04:11:35:14 VALID
PGET_SALARY PROCEDURE 04-OCT-11:12:06:52 2011-10-04:11:31:12 VALID
| Packages break the cycle of dependency. source: Ask Tom |
Scenario:
- (a) Procedure A does something.
- (b) Procedure B calls Procedure A :(B depends on A)
- (c) If procedure A is recompiled, then Procedure B becomes invalid.
-- (1) - create procedure A
SQL> create or replace procedure A as
begin null; end;
/
-- (2) create procedure B. B calls A.
SQL> create or replace procedure B as
begin A; end;
/
-- (3) Check object status: A and B are VALID
SQL> select object_type, object_name, status
from user_objects
where object_name in ('A', 'B');
OBJECT_TYPE OBJECT_NAME STATUS
------------------- ------------- -------
PROCEDURE A VALID
PROCEDURE B VALID
--(4) B depends on A. If you modify A, B becomes invalid.
SQL> create or replace procedure A as
x number;
begin
x :=1;
null;
end;
/
SQL> select object_type, object_name, status
from user_objects
where object_name in ('A', 'B');
OBJECT_TYPE OBJECT_NAME STATUS
------------------- -------------- -------
PROCEDURE A VALID
PROCEDURE B INVALID
Now, if A and B are within PACKAGES:
SQL> create or replace package a as
procedure a; end;
/
SQL> create or replace package b as
procedure b; end;
/
SQL> create or replace package body a as
procedure a is
begin null; end;
end;
/
SQL> create or replace package body b as
procedure b is
begin a.a; end;
end;
/
SQL> select object_type, object_name, status
from user_objects
where object_name in ('A', 'B');
OBJECT_TYPE OBJECT_NAME STATUS
------------------- ------------ -------
PACKAGE A VALID
PACKAGE BODY A VALID
PACKAGE B VALID
PACKAGE BODY B VALID
-- Now, if package body B is modified:
SQL> create or replace package body a as
procedure a is
x number;
begin
x:=1;
null;
end;
end;
SQL> select object_type, object_name, status
from user_objects
where object_name in ('A', 'B');
OBJECT_TYPE OBJECT_NAME STATUS
------------------- ------------- -------
PACKAGE A VALID
PACKAGE BODY A VALID
PACKAGE B VALID
PACKAGE BODY B VALID
Here package B remains VALID.
- This is because only package BODY b was modified.
As long as the spec does not change, package B will remain valid.
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