Oracle PL/SQL Bulk binds

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Abstract: Developers - If you are not using Bulk Binds you are not writing PL/SQL efficiently!

Bulk binding has been around for a long time, yet there are sites out there that don't utilise this feature to its full extent, if at all. Every release of Oracle improves on this functionality so obviously it's a topic worthy of consistent awareness.

In PL/SQL and SQL, there are a few nifty features related to bulk binding you may not have seen - it's not all about BULK COLLECT. Whether you're on 8i, 11g or anything in between, you'll benefit from the concepts described in this seminar and become a Bulk Binding Baron!

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  • Good excuse for cheese
  • Scott from Sage – Consultant & Trainer
  • Scott from Sage – Consultant & Trainer
  • Scott from Sage – Consultant & Trainer
  • Scott from Sage – Consultant & Trainer
  • Back to the business at hand
  • But it can only be done in the right context
  • We’ll also have a look at theses
  • Can be like a 3GL array
  • Get comfortable
  • Get comfortable with them
  • Depending on what you’re doing
  • Process/program global area
  • I’ll show you how to get oracle in a knot later
  • Consider this, but be very careful
  • Associative arrays – I’d imagine most are familiar with index-by tables – most flexible, used in my demos for bulk binds
  • The other two are sometimes talked about the same, can be defined as a column in a table or an object.
    No index by clause
  • VARRAYS are dense, must remove elements from end of array - FILO
  • A little boring and makes you think…
  • As Guy mentioned, you can use pl/sql tuning tools to see essentially how much time spent in each engine
  • Well if you saw Guy’s presentation, you’d think that one day you could do this and the database will just code itself.
  • Doesn’t need to be from a massive table
  • You will need this keyword to avoid memory issues
  • How able a real world example?
  • There are great examples out there showing how to improve auditing functionality with compound triggers
  • Very minor change in the code.
  • Come on, I think we’ve ALL done this in the past, I’m pretty sure I have. Especially in my Pascal days.
  • And we can easily combine the two
  • I’m considering in & out binding...
  • Remember the golden rule
  • On the line of “when wouldn’t you”, perhaps you’re thinking, well, if I gather info in bulk, do a heap of operations in the meantime, all of a sudden I have a sparse collection – how do I use FORALL with FIRST..LAST? It ain’t gonna cut it.
  • Introduced in 10g, probably the best advancement in bulk binds since it was introduced in 8i
  • For all elements in the array, update using the relevant empno (value) found
  • For all VALUES of t_index, update USING t_emp
    T_index index defines
    - order
    - frequency
  • You’re out of support…apparently
  • You can prepare for future versions using conditional compilation
    In the meantime slide the array to fill the gaps
  • … but that may not always be feasible.
    Alternatively, we could use object types and skip forall:
  • Theoretically no “order” to their elements
    Makes set operations critical!
  • I noticed those with synesthesia may have trouble with the next few slides
  • Yes, you can operate these functions on itself, but there’s and easier way to get a distinct set.
  • But this doesn’t really modify our data – but it was a LOT harder to do in earlier versions.
  • I promised to talk about memory issues
  • Yep, my sister is the graphic designer... I’m the computer guy in the family
  • If we want to process chunks of data from a large set, we can’t really use any of these.
    As awesome as sample is….
  • When I first saw this I thought “what’s the point, how do we process the rest? Do we have to flag rows processed”
    No! It’s to consider memory ramifications. Process a chunk of data each iteration, and then look at the next, automatically overriding previous collection.
    Test on your system what the “magic number” is regarding chunk size.
    Just don’t forget the exit condition like I did when I was setting up my performance comparisons.
  • There are a couple of variations. Where do I put that exit condition, for example.
  • And be totally sure where you would like your exit condition.
  • Note it doesn’t go into the third iteration
  • Steve Feuerstein described it as an “oddity” – along with something fixed in 10g release (fetching into collection of records using limit).
    It makes sense to me. How do you process a chunk at a time using an implicit cursor?!
  • What should be considered an oddity
  • Note the output after the FORALL UPDATE – it doesn’t get executed, yet the DML has been applied!
    Note is saves the error code, not the actual error text – hence the missing constraint
  • See! The data has been updated, even though exception was raised.
  • You don’t need to convert data timings into pretty graphs, enterprise manager can also graphically let you know some differences.
  • Yep, still improvements in 11g. So it’s not an old topic that everyone knows and uses.
    Other features of 11g also conducive to bulk operations, such as the compound audit trigger in Connor’s 11g presentation.
  • No longer an issue in 11g.
    This may have also have improved some of the timings in the graphs I showed, but I wanted to compares apples to apples.
  • Because a rule of thumb is a principle with broad application not intended to be strictly accurate or reliable for all situations
  • Oracle PL/SQL Bulk binds

    1. 1. SAGE Computing Services Customised Oracle Training Workshops and Consulting BulkBinds Be A Bulk Binding Baron Sco tt We sle y Syste m s Co nsultant & Traine r
    2. 2. who_am_i;
    3. 3. http://strategy2c.wordpress.com/2009/01/10/strategy-for-goldfish-funny-illustration-by-frits/
    4. 4. bulk binds
    5. 5. been around since 8i
    6. 6. not used often enough
    7. 7. binding is the assignment of values to placeholders in SQL statements my_column = :my_value
    8. 8. Bulk Binding is binding an array of values my_column = my_array(i)
    9. 9. in-bind my_variable insert update merge
    10. 10. out-bind my_variable returning
    11. 11. define my_variable fetch select
    12. 12. multiset
    13. 13. A quick word on Collections
    14. 14. lists or sets of information
    15. 15. invaluable
    16. 16. can be faster than SQL
    17. 17. cache frequent access in PGA
    18. 18. my_module (pt_array IN OUT NOCOPY t_array)
    19. 19. types of collections
    20. 20. • Associative Arrays (aka index-by tables) – Only PL/SQL – Sparse – Can have negative indexes – Similar to hash table concept – Different datatypes for indexes – TYPE type _ nam e IS TABLE OF e le m e nt_ type [NOT NULL] INDEX BY [PLS_INTEGER | BINARY_INTEGER | VARCHAR2(siz e _ lim it)]; TYPE emp_tab IS TABLE OF employees %ROWTYPE INDEX BY PLS_INTEGER;
    21. 21. • Nested Tables – Can use in SQL – Unbounded – Good for set operations – TYPE type _ nam e IS TABLE OF e le m e nt_ type [NOT NULL]; TYPE top_emp IS TABLE OF employees.employee_id%TYPE; CREATE TYPE galaxy AS TABLE OF star_object;
    22. 22. • VARRAY – Specify maximums – Dense – Can use in SQL – Most similar to 3GL array – TYPE type _ nam e IS {VARRAY | VARYING ARRAY} (siz e _ lim it) OF e le m e nt_ type [NOT NULL]; TYPE Calendar IS VARRAY(366) OF DATE; CREATE TYPE rainbow AS VARRAY(7) OF VARCHAR2(64); CREATE TYPE solar_system AS VARRAY(8) OF planet_object;
    23. 23. back to the business of binds
    24. 24. from the 8.1.7 documentation
    25. 25. Conventional Bind Performance penalty for many context switches Oracle Server PL/SQL Runtime Engine PL/SQL block Procedural statement executor SQL Engine SQL statement executorFOR r_emp IN c_emp LOOP UPDATE emp SET sal = sal * 1.1 WHERE empno = r_emp.empno; END LOOP;
    26. 26. Bulk Bind Much less overhead Oracle Server PL/SQL Runtime Engine PL/SQL block Procedural statement executor SQL Engine SQL statement executorFORALL i IN INDICES OF t_emp UPDATE emp SET sal = sal * 1.1 WHERE empno = t_emp(i);
    27. 27. when would you use it?
    28. 28. plsql_optimize_level = 42
    29. 29. lifesgoldenrule.com
    30. 30. no bulk bind – do it in SQL
    31. 31. “If the DML statement affects four or more database rows, the use of bulk SQL can improve performance considerably” - Oracle Documentation
    32. 32. SELECT everyone BULK COLLECT INTO my_array FROM the_worlds_idiots;
    33. 33. SELECT everyone BULK COLLECT INTO my_array LIMIT 100 FROM the_worlds_idiots;
    34. 34. reoccurring SQL within PL/SQL loop
    35. 35. multiple operations on dataset – BULK COLLECT
    36. 36. http://www.sharenator.com/Before_After/stinejensen_530-65109.html
    37. 37. 11g compound triggers – auditing
    38. 38. finally some coding examples?
    39. 39. DML Bind Example -- Slower method, running the UPDATE -- statements within a regular loop FOR i IN t_emp.FIRST..t_emp.LAST LOOP UPDATE emp_largish SET sal = sal * 1.1 WHERE empno = t_emp(i); END LOOP; 1.94 seconds -- Efficient method, using a bulk bind on a VARRAY FORALL i IN t_emp.FIRST..t_emp.LAST UPDATE emp_largish SET sal = sal * 1.1 WHERE empno = t_emp(i); 1.40 seconds
    40. 40. Collect Example -- Slower method, assigning each -- collection element within a loop. v_index := 0; FOR r_emp IN c_emp LOOP v_index := v_index + 1; t_emp(v_index).empno := r_emp.empno; t_emp(v_index).ename := r_emp.ename; END LOOP; 0.19 seconds -- Efficient method, using a bulk bind OPEN c_emp; FETCH c_emp BULK COLLECT INTO t_emp; CLOSE c_emp; 0.09 seconds
    41. 41. Example of Combination -- Slower method, running update -- statement within regular loop, -- returning individual elements FOR i IN t_emp.FIRST..t_emp.LAST LOOP UPDATE emp_largish SET sal = sal * 1.1 WHERE empno = t_emp(i) RETURNING sal INTO t_sal(i); END LOOP; 0.75 seconds -- Efficient method, using a bulk bind -- and bulk collect FORALL i IN t_emp.FIRST..t_emp.LAST UPDATE emp_largish SET sal = sal * 1.1 WHERE empno = t_emp(i) RETURNING sal BULK COLLECT INTO t_sal; 0.29 seconds
    42. 42. when wouldn’t you use it
    43. 43. lifesgoldenrule.com
    44. 44. can you just do it in SQL? when you only need one iteration just filter records with where/intersect/minus when you haven't tested it with & without >= 10g may silently do it for you too much data?
    45. 45. what if I have a sparse collection?
    46. 46. Uh oh… DECLARE TYPE emp_tab IS TABLE OF emp.empno%TYPE INDEX BY PLS_INTEGER; t_emp emp_tab; CURSOR c_emp IS SELECT empno FROM emp; BEGIN OPEN c_emp; FETCH c_emp BULK COLLECT INTO t_emp; CLOSE c_emp; -- ...do a bunch of processing, including -- something like: t_emp.DELETE(3); FORALL i IN t_emp.FIRST..t_emp.LAST UPDATE emp SET sal = sal * 1.1 WHERE empno = t_emp(i); END; / ORA-22160: element at index [3] does not exist ORA-06512: at line 15
    47. 47. processing spare collections
    48. 48. introduced in 10g
    49. 49. INDICES OF allows iteration of all index values, not just from lower to upper bound (tab.FIRST..tab.LAST)
    50. 50. VALUES OF Create PL/SQL table effectively indexing your collection - process specific elements - process in particular order - process an element more than once
    51. 51. simple FORALL i IN t_emp.FIRST..t_emp.LAST UPDATE emp SET sal = sal * 1.1 WHERE empno = t_emp(i); FIRST LAST Updated all rows In order of array listing
    52. 52. simple FORALL i IN t_emp.FIRST..t_emp.LAST UPDATE emp SET sal = sal * 1.1 WHERE empno = t_emp(i); FIRST LAST ORA-22160: element at index [3] does not exist
    53. 53. clever FORALL i IN INDICES OF t_emp UPDATE emp SET comm = comm * 1.5 WHERE empno = t_emp(i); 7890 7988 7752 7521 7900 Updated rows within array In order of array listing t_emp(3) := 7890 t_emp(5) := 7988 t_emp(6) := 7752 t_emp(8) := 7521 t_emp(9) := 7900
    54. 54. advanced 7890 7988 7752 t_index(-2):= 6 t_index( 0):= 3 t_index( 3):= 5 t_index(10):= 6 t_emp(9) := 7900 t_emp(8) := 7521 t_emp(6) := 7752 t_emp(5) := 7988 t_emp(3) := 7890 FORALL i IN VALUES OF t_index UPDATE emp SET comm = comm * 1.5 WHERE empno = t_emp(i); DECLARE TYPE emp_tab IS TABLE OF emp.empno%TYPE INDEX BY PLS_INTEGER; TYPE numlist IS TABLE OF PLS_INTEGER INDEX BY BINARY_INTEGER; t_emp emp_tab; t_indexes numlist; BEGIN t_emp(3) := 7890; t_emp(5) := 7988; t_emp(6) := 7752; t_emp(8) := 7521; t_emp(9) := 7900; t_indexes(-2) := 6; t_indexes(0) := 3; t_indexes(3) := 5; t_indexes(10) := 6;
    55. 55. what if I have 9i?
    56. 56. CREATE OR REPLACE PACKAGE BODY sw_bulk_insert IS PROCEDURE sw_insert (sw_tab IN t_sw_tab) IS BEGIN $IF dbms_db_version.ver_le_9 $THEN DECLARE l_dense t_sw_tab; ln_index PLS_INTEGER := sw_tab.FIRST; BEGIN << dense_loop >> WHILE (l_index IS NOT NULL) LOOP l_dense(l_dense.COUNT + 1) := sw_tab(l_index); l_index := sw_tab.NEXT(l_index); END LOOP dense_loop; FORALL i IN 1..l_dense.COUNT INSERT INTO sw_table VALUES l_dense(i); END; $ELSE FORALL i IN INDICES OF sw_tab INSERT INTO sw_table VALUES sw_tab(i); $END END sw_insert; END sw_bulk_insert;
    57. 57. DECLARE t_emp t_emp_obj; BEGIN SELECT emp_obj(empno, ename, job, mgr, hiredate, sal, comm, deptno) BULK COLLECT INTO t_emp FROM emp; -- Remove those with commission to create sparse collection FOR i IN 1..t_emp.COUNT LOOP IF t_emp(i).comm IS NOT NULL THEN t_emp.DELETE(i); END IF; END LOOP; -- No need for FORALL INSERT INTO emp2 SELECT * FROM TABLE(CAST(t_emp AS t_emp_obj)); END; / CREATE TABLE emp2 AS SELECT * FROM emp WHERE 1=0; CREATE OR REPLACE TYPE emp_obj AS OBJECT (empno NUMBER(4) ,ename VARCHAR2(10) ,job VARCHAR2(9) ,mgr NUMBER(4) ,hiredate DATE ,sal NUMBER(7,2) ,comm NUMBER(7,2) ,deptno NUMBER(2)) / CREATE OR REPLACE TYPE t_emp_obj AS TABLE OF emp_obj /
    58. 58. can I do this "bunch of processing" in bulk, outside the db?
    59. 59. DECLAREDECLARE TYPE emp_tab IS TABLE OF emp.empno%TYPE INDEX BY PLS_INTEGER;TYPE emp_tab IS TABLE OF emp.empno%TYPE INDEX BY PLS_INTEGER; t_emp emp_tab;t_emp emp_tab; CURSOR c_emp ISCURSOR c_emp IS SELECT empno FROM emp;SELECT empno FROM emp; BEGINBEGIN OPEN c_emp;OPEN c_emp; FETCH c_emp BULK COLLECT INTO t_emp;FETCH c_emp BULK COLLECT INTO t_emp; CLOSE c_emp;CLOSE c_emp; -- ...do a bunch of processing, including -- something like: t_emp.DELETE(3); FORALL i IN t_emp.FIRST..t_emp.LASTFORALL i IN t_emp.FIRST..t_emp.LAST UPDATE empUPDATE emp SET sal = sal * 1.1SET sal = sal * 1.1 WHERE empno = t_emp(i);WHERE empno = t_emp(i); END;END; // -- ... Or just those employees that exist in another collection -- t_emp intersect with t_emp_leaders;
    60. 60. MULTISET operations
    61. 61. nested tables ONLY
    62. 62. DECLARE TYPE colours IS TABLE OF VARCHAR2(64); comp1 colours; comp2 colours; result colours; PROCEDURE show_table (p_table IN colours) IS BEGIN FOR i IN p_table.FIRST..p_table.LAST LOOP DBMS_OUTPUT.PUT (p_table(i)||' '); END LOOP; DBMS_OUTPUT.NEW_LINE; END; BEGIN comp1 := colours('Black','White','Red','Red'); comp2 := colours('Black','Red','Yellow'); result := comp1 MULTISET UNION comp2; dbms_output.put_line ('multiset union is '); show_table(result); END; / multiset union is Black White Red Red Black Red Yellow
    63. 63. ... BEGIN comp1 := colours('Black','White','Red','Red'); comp2 := colours('Black','Red','Yellow'); result := comp1 MULTISET UNION DISTINCT comp2; dbms_output.put_line ('multiset union distinct is '); show_table(result); END; / multiset union distinct is Black White Red Yellow
    64. 64. ... BEGIN comp1 := colours('Black','White','Red','Red'); comp2 := colours('Black','Red','Yellow'); result := comp1 MULTISET INTERSECT DISTINCT comp2; dbms_output.put_line ('multiset intersect distinct is '); show_table(result); END; / multiset intersect distinct is Black Red
    65. 65. ... BEGIN comp1 := colours('Black','White','Red','Red'); comp2 := colours('Black','Red','Yellow'); result := comp1 MULTISET EXCEPT DISTINCT comp2; dbms_output.put_line ('multiset except distinct is '); show_table(result); END; / multiset except distinct is White
    66. 66. ... BEGIN comp1 := colours('Black','White','Red','Red'); comp1 := comp1 MULTISET UNION DISTINCT comp1; dbms_output.put_line (‘self multiset intersect distinct is '); show_table(comp1); END; / self multiset union distinct is Black White Red
    67. 67. DECLARE TYPE colours IS TABLE OF VARCHAR2(64); t_colours colours := colours('Black','White','Red','Red'); PROCEDURE show_table (p_table IN colours) ... BEGIN DBMS_OUTPUT.PUT_LINE('Count:'||CARDINALITY(t_colours)); DBMS_OUTPUT.PUT_LINE('Distinct:'||CARDINALITY(SET(t_colours))); IF t_colours IS NOT A SET THEN t_colours := SET(t_colours); show_table(t_colours); END IF; END; / Count:4 Distinct:3 Black White Red
    68. 68. but wait, there's still more...
    69. 69. Equality DECLARE TYPE colours IS TABLE OF VARCHAR2 (64); group1 colours := colours ('Black', 'White'); group2 colours := colours ('White', 'Black'); group3 colours := colours ('White', 'Red'); BEGIN IF group1 = group2 THEN DBMS_OUTPUT.PUT_LINE ('Group 1 = Group 2'); ELSE DBMS_OUTPUT.PUT_LINE ('Group 1 != Group 2'); END IF; IF group2 != group3 THEN DBMS_OUTPUT.PUT_LINE ('Group 2 != Group 3'); ELSE DBMS_OUTPUT.PUT_LINE ('Group 2 = Group 3'); END IF; END; /
    70. 70. DECLARE TYPE colours IS TABLE OF VARCHAR2(64); t_colours colours := colours('Black','White','Red','Red'); v_colour VARCHAR2(64) := 'Black'; BEGIN IF v_colour MEMBER OF t_colours THEN DBMS_OUTPUT.PUT_LINE('Exists'); ELSE DBMS_OUTPUT.PUT_LINE(‘Absent'); END IF; END; / Exists Membership
    71. 71. DECLARE TYPE colours IS TABLE OF VARCHAR2(64); t_colours colours := colours('Black','White','Red','Yellow'); t_colours2 colours := colours('Black','Red'); t_colours3 colours := colours('Black','Blue'); BEGIN IF t_colours2 SUBMULTISET OF t_colours THEN DBMS_OUTPUT.PUT_LINE('2 Subset'); ELSE DBMS_OUTPUT.PUT_LINE('2 Separate'); END IF; IF t_colours3 SUBMULTISET OF t_colours THEN DBMS_OUTPUT.PUT_LINE('3 Subset'); ELSE DBMS_OUTPUT.PUT_LINE('3 Separate'); END IF; END; / 2 Subset 3 Separate Subset
    72. 72. DECLARE TYPE t_c IS TABLE OF VARCHAR2(32767) INDEX BY PLS_INTEGER; l_c t_c; BEGIN SELECT LPAD('x',32767,'x') bb BULK COLLECT INTO l_c FROM DUAL CONNECT BY LEVEL <=1000000; END; / declare * ERROR at line 1: ORA-04030: out of process memory when trying to allocate 16396 bytes (koh-kghu call ,pl/sql vc2) ORA-06512: at line 5 Elapsed: 00:00:02.70 Boom!
    73. 73. limiting data
    74. 74. prevent collections from expanding with no limit
    75. 75. SELECT sal BULK COLLECT INTO t_emp FROM emp WHERE ROWNUM <= 10; WHERE ROWNUM BETWEEN 11 AND 20 – Won’t work FROM emp SAMPLE(10) -- “Random” -- Performance hit: SELECT * FROM ( SELECT ROW_NUMBER() OVER (ORDER BY empno) AS from_to_rank …) WHERE from_to_rank BETWEEN 1 AND 10
    76. 76. LIMIT clause
    77. 77. DECLARE v_rows PLS_INTEGER := 10; BEGIN OPEN c_emp; LOOP FETCH c_emp BULK COLLECT INTO t_emp LIMIT v_rows; EXIT WHEN t_emp.COUNT = 0; null; -- (Process information) END LOOP; CLOSE c_emp;
    78. 78. take care with the exit condition
    79. 79. OPEN c_emp; LOOP FETCH c_emp BULK COLLECT INTO t_emp LIMIT v_rows; EXIT WHEN t_emp.COUNT = 0; -- Here? null; -- (Process information) EXIT WHEN c_emp%NOTFOUND; -- or here? END LOOP; CLOSE c_emp; EXCEPTION WHEN NO_DATA_FOUND -- Does this get raised?
    80. 80. t_emp.COUNT = 0 ** Count:10 CLARK JAMES MARTIN MILLER WARD KING ALLEN ADAMS SMITH JONES ** Count:4 TURNER BLAKE SCOTT FORD ** Count:0 PL/SQL procedure successfully completed. LOOP FETCH c_emp BULK COLLECT INTO t_emp LIMIT 10; dbms_output.put_line('** Count:'||t_emp.COUNT); EXIT WHEN t_emp.COUNT = 0; dbms_output.put_line(t_emp(i).ename); -- EXIT WHEN c_emp%NOTFOUND;
    81. 81. WHEN c_emp%NOTFOUND ** Count:10 CLARK JAMES MARTIN MILLER WARD KING ALLEN ADAMS SMITH JONES ** Count:4 TURNER BLAKE SCOTT FORD PL/SQL procedure successfully completed. LOOP FETCH c_emp BULK COLLECT INTO t_emp LIMIT 10; dbms_output.put_line('** Count:'||t_emp.COUNT); -- EXIT WHEN t_emp.COUNT = 0; dbms_output.put_line(t_emp(i).ename); EXIT WHEN c_emp%NOTFOUND;
    82. 82. implicit cursors don’t bulk up
    83. 83. DECLARE TYPE emp_tab IS TABLE OF emp.empno%TYPE INDEX BY PLS_INTEGER; t_emp emp_tab; BEGIN SELECT empno BULK COLLECT INTO t_emp FROM emp LIMIT 10; END; / LIMIT 10 * ERROR at line 8: ORA-06550: line 8, column 9: PL/SQL: ORA-00933: SQL command not properly ended ORA-06550: line 5, column 3: PL/SQL: SQL Statement ignored
    84. 84. and if I have no data?
    85. 85. NO_DATA_FOUND DECLARE v_sal emp.sal%TYPE; BEGIN SELECT sal INTO v_sal FROM emp WHERE 1=0; END; / DECLARE * ERROR at line 1: ORA-01403: no data found ORA-06512: at line 4 DECLARE TYPE emp_tab IS TABLE OF emp.sal%TYPE INDEX BY PLS_INTEGER; t_emp emp_tab; BEGIN SELECT sal BULK COLLECT INTO t_emp FROM emp WHERE 1=0; END; / PL/SQL procedure successfully completed.
    86. 86. bulk attributes
    87. 87. Bulk Cursor Attributes DECLARE TYPE dept_list IS TABLE OF NUMBER; t_dept dept_list := dept_list(10, 20, 30); BEGIN FORALL i IN t_dept.FIRST..t_dept.LAST DELETE FROM emp WHERE deptno = t_dept(i); -- Each indice may update multiple rows dbms_output.put_line('Total rows affected: '||SQL%ROWCOUNT); -- How many rows were affected by each delete statement? FOR j IN t_dept.FIRST..t_dept.LAST LOOP dbms_output.put_line('Dept '||t_dept(j)|| 'rows:'||SQL%BULK_ROWCOUNT(j)); END LOOP; END; / Total rows affected: 14 Dept 10 rows:3 Dept 20 rows:5 Dept 30 rows:6 PL/SQL procedure successfully completed.
    88. 88. what if we have exceptions for a particular row?
    89. 89. CREATE TABLE emp2 AS SELECT * FROM emp; ALTER TABLE emp2 ADD CONSTRAINT be_test CHECK (sal = ROUND(sal));DECLARE TYPE emp_list IS TABLE OF NUMBER; t_emp emp_list := emp_list(7934, 7782, 7839, 7788, 7900); e_dml_errors EXCEPTION; PRAGMA exception_init(e_dml_errors, -24381); BEGIN FORALL i IN t_emp.FIRST..t_emp.LAST SAVE EXCEPTIONS -- Will raise exception for sal of 1250 but not 1300 UPDATE emp2 SET sal = sal/100 WHERE empno = t_emp(i); dbms_output.put_line('Total rows affected: ‘ ||SQL%ROWCOUNT); EXCEPTION WHEN e_dml_errors THEN -- Now we figure out what failed and why. dbms_output.put_line('Total failed updates: '||SQL%BULK_EXCEPTIONS.COUNT); FOR j IN 1..SQL%BULK_EXCEPTIONS.COUNT LOOP dbms_output.put_line('Error '||j||' for indice ‘ ||SQL%BULK_EXCEPTIONS(j).ERROR_INDEX); dbms_output.put_line('Error message is ‘ ||SQLERRM(-SQL%BULK_EXCEPTIONS(j).ERROR_CODE)); END LOOP; END; Total failed updates: 2 Error 1 for indice 2 Error message is ORA-02290: check constraint (.) violated Error 2 for indice 5 Error message is ORA-02290: check constraint (.) violated PL/SQL procedure successfully completed.
    90. 90. Bulk Exceptions select empno, ename, sal from emp2 where empno in (7934, 7782, 7839, 7788, 7900); EMPNO ENAME SAL ---------- ---------- ---------- 7934 MILLER 13 7782 CLARK 2450 7839 KING 50 7788 SCOTT 30 7900 JAMES 950 5 rows selected.
    91. 91. 41% 33% 10% 9% 7% FOR CURSOR COLLECT LIMIT100 IISS 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 10g 11g Indices1000 Indices100 Limit1000 Limit100 0 50 100 150 200 250 300 9i 10g 11g Limit 100 Limit 1000 0% 20% 40% 60% 80% 100% 9i 10g 11g IISS Limit100 Collect Cursor For
    92. 92. FOR CURSOR COLLECT LIMIT100 IISS
    93. 93. Enterprise Manager Limit 100 vs 1000 Separate runs of For | Cursor | Collect | Limit | IISS
    94. 94. What’s new? • 8i – Bulk operations! – Collections indexed by BINARY_INTEGER only • 9i – Bulk collect via dynamically opened ref cursor • 9i Release 2 – Bulk collect into collection of records – Index by VARCHAR2 & BINARY_INTEGER (or their subtypes) • 10g – PL/SQL engine may decide to peform array fetching for you – INDICES OF/VALUES OF introduced – MULTISET operations • 11g – table(bulk_index).field is now supported at run-time – DBMS_SQL allows bulk binds using user-define collection types
    95. 95. CREATE TABLE emp2 AS SELECT empno,ename,sal, SYSTIMESTAMP ts FROM emp WHERE 1=0; DECLARE CURSOR sw IS SELECT empno, ename, sal FROM emp; TYPE t_sw IS TABLE OF sw%ROWTYPE; lt_sw t_sw; BEGIN OPEN sw; FETCH sw BULK COLLECT INTO lt_sw; CLOSE sw; FORALL i IN lt_sw.FIRST..lt_sw.LAST INSERT INTO emp2 VALUES (lt_sw(i).empno ,lt_sw(i).ename ,lt_sw(i).sal ,SYSTIMESTAMP); END; / values (lt_sw(i).empno * ERROR at line 11: ORA-06550: line 11, column 9: PLS-00436: implementation restriction: cannot reference fields of BULK In-BIND table of records
    96. 96. some final words
    97. 97. Read appropriate documentation
    98. 98. READ THIS… TWICE! • Tom Kyte – In search of the truth - Or Correlation is not Causation – http://asktom.oracle.com/pls/ask/download_file?p_file=3067171813508 – “If any pape r yo u re ad te lls yo u what but no t why, re g ardle ss o f its tim e stam p, Isug g e st yo u take its advice with a big g rain o f salt as it m ay be applicable onlyto onlyspecific cases andnot applicabletoyouat all. In fact, it co uld be so m e thing that was true in the past and no t true anym o re . If theygiveyouno wayto findout, ignoreit. ”
    99. 99. things change
    100. 100. it only takes one case to show something is...
    101. 101. not universally true
    102. 102. Rules of thumb without evidence, without ways to test them before implementing them, are dangerous, seriously dangerous “Because a rule of thumb is a principle with broad application not intended to be strictly accurate or reliable for all situations”
    103. 103. SAGE Computing Services Customised Oracle Training Workshops and Consulting Questions and Answers? Presentations are available from our website: http: //www. sag e co m puting . co m . au e nq uirie s@ sag e co m puting . co m . au sco tt. we sle y@ sag e co m puting . co m . au http: //triang le -circle -sq uare . blo g spo t. co m

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