Using bulk collect clause- bulk bind performance improvement, PL-SQL Programming

Assignment Help:

Using the BULK COLLECT Clause

The keywords BULK COLLECT specify the SQL engine to bulk-bind output collections before returning them to the PL/SQL engine. You can use these keywords in the FETCH INTO, SELECT INTO, and RETURNING INTO clauses. The syntax for the above is shown below:

... BULK COLLECT INTO collection_name[, collection_name] ...

The SQL engine bulk-binds all the collections referenced in the INTO list. The parallel columns should store the scalar (not composite) values. In the illustration, the SQL engine loads the whole empno and ename database columns into the nested tables before returning the tables to the PL/SQL engine:

DECLARE

TYPE NumTab IS TABLE OF emp.empno%TYPE;

TYPE NameTab IS TABLE OF emp.ename%TYPE;

enums NumTab; -- no need to initialize

names NameTab;

BEGIN

SELECT empno, ename BULK COLLECT INTO enums, names FROM emp;

...

END;

The SQL engine initializes and then expands the collections for you. (Though, it cannot expands the varrays beyond their maximum size.) Then, starting at index 1, it inserts the elements successively and overwrites any pre-existent elements.

The SQL engine bulk-binds the whole database columns. Therefore, if a table has 50,000 rows, then the engine loads 50,000 column values into the target collection. Though, you can use the pseudocolumn ROWNUM to limit the number of rows processed. In the illustration below, you limit the number of rows to 100:

DECLARE

TYPE NumTab IS TABLE OF emp.empno%TYPE;

sals NumTab;

BEGIN

SELECT sal BULK COLLECT INTO sals FROM emp WHERE ROWNUM <= 100;

...

END;


Related Discussions:- Using bulk collect clause- bulk bind performance improvement

Using rollback - , Using ROLLBACK The ROLLBACK statements end the pres...

Using ROLLBACK The ROLLBACK statements end the present transaction and undo any change made during the transaction. The Rolling back is helpful for two reasons. Firstly, if yo

Character types in pl/sql, Character Types The Character types allow yo...

Character Types The Character types allow you to store alphanumeric data, represent words and text, and manipulate the character strings. CHAR You use the CHAR dataty

Using bulk collect clause- bulk bind performance improvement, Using the BUL...

Using the BULK COLLECT Clause The keywords BULK COLLECT specify the SQL engine to bulk-bind output collections before returning them to the PL/SQL engine. You can use these ke

Keyword and parameter description - delete statement, Keyword and Parameter...

Keyword and Parameter Description: table_reference: This specifies a table or view that should be accessible when you execute the DELETE statement, and for that you must

Recursion, Recursion The Recursion is a powerful method for simplify th...

Recursion The Recursion is a powerful method for simplify the design of the algorithms. Principally, the recursion means the self-reference. In the recursive mathematical serie

Data types in sql - integer, Data Types in SQL - Integer INTEGER or  s...

Data Types in SQL - Integer INTEGER or  synonymously INT, for integers within a certain range. SQL additionally has types SMALLINT and BIGINT for certain ranges of integers. T

Referencing records, Referencing Records Unlike the elements in a coll...

Referencing Records Unlike the elements in a collection, that are accessed using subscripts, the fields in a record are accessed by name. To reference an individual field, you

Scope rules - user-defined exceptions, Scope Rules You cannot declare ...

Scope Rules You cannot declare an exception twice in the similar block. Though, you can, declare the similar exception in 2 different blocks. The Exceptions declared in a bloc

Develop data business intelligence project, Develop Data Business Intellige...

Develop Data Business Intelligence Project Project Description: We are linking our Microsoft SQL Database to GoodData Business Intelligence. We are seeking somebody who has e

Relational operators and logical operators, Relational Operators and Logica...

Relational Operators and Logical Operators It prepares the ground for subsequent sections in which each specific relational operator is paired with its logical counterpart, su

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