How bulk bind helps improvement in performance?, PL-SQL Programming

Assignment Help:

How Bulk Binds Improve Performance

The assigning of values to the PL/SQL variables in SQL statements is known as binding.

The binding of the whole collection at once is known as the bulk binding. The Bulk binds improve performance by minimizing the number of the context switches between the PL/SQL and SQL engines. With the bulk binds, whole collections, not just an individual element, are passed back and forth. For illustration, the DELETE statement below is sent to the SQL engine just once, with the whole nested table:

DECLARE

TYPE NumList IS TABLE OF NUMBER;

mgrs NumList := NumList(7566, 7782, ...); -- manager numbers

BEGIN

...

FORALL i IN mgrs.FIRST..mgrs.LAST

DELETE FROM emp WHERE mgr = mgrs(i);

END;

In the illustration below, 5000 part numbers and names are loaded into the index-by tables. Then, all the table elements are inserted into a database table twice. At First, they are inserted using a FOR loop, that completes in 38 seconds. Then, they are bulk-inserted by using a FORALL statement that completes in only 3 seconds.

SQL> SET SERVEROUTPUT ON

SQL> CREATE TABLE parts (pnum NUMBER(4), pname CHAR(15));

Table created.

SQL> GET test.sql

1 DECLARE

2 TYPE NumTab IS TABLE OF NUMBER(4) INDEX BY BINARY_INTEGER;

3 TYPE NameTab IS TABLE OF CHAR(15) INDEX BY BINARY_INTEGER;

4 pnums NumTab;

5 pnames NameTab;

6 t1 CHAR(5);

7 t2 CHAR(5);

8 t3 CHAR(5);

9 PROCEDURE get_time (t OUT NUMBER) IS

10 BEGIN SELECT TO_CHAR(SYSDATE,'SSSSS') INTO t FROM dual; END;

11 BEGIN

12 FOR j IN 1..5000 LOOP -- load index-by tables

13 pnums(j) := j;

14 pnames(j) := 'Part No. ' || TO_CHAR(j); 15 END LOOP;

16 get_time(t1);

17 FOR i IN 1..5000 LOOP -- use FOR loop

18 INSERT INTO parts VALUES (pnums(i), pnames(i));

19 END LOOP;

20 get_time(t2);

21 FORALL i IN 1..5000 -- use FORALL statement

22 INSERT INTO parts VALUES (pnums(i), pnames(i));

23 get_time(t3);

24 DBMS_OUTPUT.PUT_LINE('Execution Time (secs)');

25 DBMS_OUTPUT.PUT_LINE('---------------------');

26 DBMS_OUTPUT.PUT_LINE('FOR loop: ' || TO_CHAR(t2 - t1));

27 DBMS_OUTPUT.PUT_LINE('FORALL: ' || TO_CHAR(t3 - t2));

28* END;

SQL> /

Execution Time (secs)

---------------------

FOR loop: 38

FORALL: 3

PL/SQL process successfully completed.

In the bulk-bind input collections, you can use the FORALL statement. And in the bulk-bind output collections, you can use the BULK COLLECT clause.


Related Discussions:- How bulk bind helps improvement in performance?

Need fullcalendar modifications, Project Description: I am looking to ch...

Project Description: I am looking to change FullCalendar to add/delete sql server data when events are removed or dropped from Calendar. Events should only be included by dra

Cursors in pl/sql, Cursors The Oracle uses work areas to execute the SQ...

Cursors The Oracle uses work areas to execute the SQL statements and to store process information. A PL/SQL construct known as the cursor. Let's you assume name a work area and

Example of foreign key constraint - sql, Example of Foreign Key Constraint ...

Example of Foreign Key Constraint Example: Alternative formulation for 6.3 as a foreign key constraint ALTER TABLE EXAM_MARK ADD CONSTRAINT Must_be_enrolled_to_take_exam

Avoiding collection exceptions, Avoiding Collection Exceptions   In ma...

Avoiding Collection Exceptions   In many cases, if you reference a nonexistent collection element, then PL/SQL raises a predefined exception. Consider the illustration shown b

Obtaining a natural join by specifying the common columns, Obtaining a natu...

Obtaining a natural join by specifying the common columns Synatax: SELECT * FROM IS_CALLED JOIN IS_ENROLLED_ON USING ( StudentId ) However, a named columns join doe

Goto statement - sequential control, GOTO Statement The GOTO statement b...

GOTO Statement The GOTO statement branches to a label unconditionally. The label must be exclusive within its scope and should precede an executable statement or a PL/SQL block.

Sql outer join, SQL outer join SELECT * FROM IS_CALLED NATURAL LEFT...

SQL outer join SELECT * FROM IS_CALLED NATURAL LEFT JOIN IS_ENROLLED_ON Note that adding LEFT to an invocation of CROSS JOIN has no effect unless the right-hand operand

Effect of anonymous columns, Effect of Anonymous Columns Now, recall t...

Effect of Anonymous Columns Now, recall that a VALUES expression denotes a table with undefined column names. If an initial value is to be specified when a base table is creat

Testing triggers, Demonstrate your knowledge of PL/SQL programming by writi...

Demonstrate your knowledge of PL/SQL programming by writing and thoroughly testing triggers and stored procedures associated with an e-commerce application that provides security l

Calculating a Shopper''s Total Spending, Many of the reports generated from...

Many of the reports generated from the system calculate the total dollars in a shopper''s purchases. Follow these steps to create a function named TOT_PURCH_SF that accepts a shopp

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd