GeekInterview.com
   Home |  Tech FAQ  |   Interview Questions |  Placement Papers |  Tech Articles |  Learn |  Freelance Projects |  Online Testing |  Geeks Talk |  Job Postings |  Knowledge Base | Site Search |  Add/Ask Question

GeekInterview.com  >  Interview Questions  >  Mainframe  >  DB2
Go To First  |  Previous Question  |  Next Question 
 DB2  |  Question 57 of 196    Print  
Compare a subselect to a join. Any subselect can be rewritten as a join, but not vice versa. Joins are usually more efficient as join rows can be returned immediately, subselects require a temporary work area for inner selects results while processing the outer select.

  
Total Answers and Comments: 0 Last Update: N/A   
  
 Sponsored Links

 

No answers are posted for this question yet.
Be the first to answer it!


 Related Questions

Describe the elements of the SELECT query syntax. SELECT element FROM table WHERE conditional statement?

Joins, unions and nested selects are used to retrieve data.  
Latest Answer : The two tables has to be linked.EXEC SQL SELECT A.EMP_ID, B.WAGE FROM Table1 A,  Table2 B WHERE A.EMP_ID = B.EMP_ID AND A.EMP_ID = ...

DDL is data definition language and DML is data manipulation language. DDL statements are CREATE, ALTER, TRUNCATE. DML statements are SELECT, INSERT, DELETE and UPDATE.  
Latest Answer : DDL(data definition language)DDL Statement are  ·          Create·          Alter and·          Drop DML(data ...

An outer join includes rows from tables when there are no matching values in the tables.  
Latest Answer : 3 types. Left outer Join----left table unmatched valyes are included.Right Outer Join---right table unmatched values are included.Full outer Join----Both table unmatched values are selected. ...

A subselect is a select which works in conjunction with another select. A nested select is a kind of subselect where the inner select passes to the where criteria for the outer select.  

Group by controls the presentation of the rows, order by controls the presentation of the columns for the results of the SELECT statement.  
Latest Answer : Group By forms Groups (of course), but this means it also SORTS; but it will also retrieve a DISTINCT RECORD SETORDER BY Sorts by the columns included in the Statement, and does not retrieve DISTINCT Records.Neither determines the order of the columns ...

An embedded sql statement may return a number of rows while the programming language can only access one row at a time. The programming device called a cursor controls the position of the row.  
Latest Answer : Cursor is a Context Area. where which can process multiples rows. ...

I/O operations are usually most critical for DB2 performance (or any other database for that matter).  
Latest Answer : I'm sorry, but the answer is a firm "It depends."Depending on various factors, most MVS boxes run short on either CPU or I/O. These factors include, workload, time of day, day of the week, etc. A capacity planner could give you a better list, but these ...

Denormalizing DB2 tables reduces the need for processing intensive relational joins and reduces the number of foreign keys.  
Latest Answer : In datawarehouse environment, mostly all the tables are semi- normalized ( ie it is fully normalized) to reduce no of joins . so de-normalization is having lot of advantages in datawarehouse . ...

SPUFI stands for SQL processing using file input. It is the DB2 interactive menu-driven tool used by developers to create database objects.  
Latest Answer : SPUFI : SQL Processing Using File Input, it supports the on-line execution of SQL statements from a TSO terminal ...


 Sponsored Links

 
Related Articles

Moving All the XML Processing into the Database

Moving All the XML Processing into the Database In the preceding example the database server performs only a part of the XML processing while the rest is still performed by the PHP engine Specifically the database server generates an employees XML document based on the records from the hr employees
 

Performing XML Processing inside the Database

Performing XML Processing inside the Database When building XML enabled applications on top of Oracle there are many advantages to performing the XML processing inside the database when compared to performing it on the client The key advantages to perform XML processing inside the database are as fo
 

Transforming and Processing XML with XSLT

Transforming and Processing XML with XSLT In the preceding example you transform XML into HTML directly in your script wrapping the data extracted from the XML document into appropriate HTML tags Alternatively you might perform an XSL Extensible Stylesheet Language transformation to get the same gen
 

XML Processing in PHP and Oracle Applications

Processing XML in PHP Oracle Applications As mentioned there are two alternatives when it comes to performing XML processing in your PHP Oracle application You can perform any required XML processing using either PHP s XML extensions or PEAR XML packages or Oracle s XML features mosgoogle In the fol
 

ODP.NET - Retrieving Multiple Rows on to the Grid

ODP NET Retrieving Multiple Rows on to the Grid In the previous section we tried to retrieve only one row using OracleDataReader In this section we will try to retrieve more than one row or a result set and populate a DataGridView on a WinForm mosgoogle The following code lists out the details of al
 

jQuery Expanding and Collapsing Table Rows

jQuery Expanding and Collapsing Table Rows The expanding and collapsing behavior added earlier also conflicts with our filters If a section is collapsed and a new filter is chosen then the matching items are displayed even if in the collapsed section Conversely if the table is filtered and a section
 

jQuery Collapsing and Expanding Table Rows

jQuery Collapsing and Expanding Table Rows When large sets of data are grouped in tables as each year s set of articles are in our News page collapsing or hiding a section s contents can be a convenient way to get a broad view of all of the table s data without having to scroll so much mosgoogle To
 

How EDI work with XML

How EDI work with XML EDI and XML systems have been seen as the opportunity to create a holistic approach to data information exchange that can deliver and process simple durable and effective business transactions by electronic means To achieve this methods must be employed that are not only of val
 

Benefits of ERP for the Financial Area

Benefits of ERP for the Financial Area At this time the main motivation of some companies for choosing ERP is to achieve an improvement in the management of their financial area Sometimes they rush into the decision without taking into consideration the real contribution of the implementation in rel
 

On-Line Transaction Processing

On-Line Transaction Processing On-Line Transaction Processing is a processing that supports the daily business operations. Also know as operational processing and OLTP.  An OLTP is a database which must typically allow the real-time processing of SQL transactions to support traditional reta
 





About Us  |   Privacy Policy  |   Terms and Conditions  |   Contact  |   Site Map  |   Add Question  |   Propose Category  |   RSS Feeds  |   Articles Sitemap  |   Site Updates  |   Add Resource

Copyright © 2005 - 2008 GeekInterview.com. All Rights Reserved
Page copy protected against web site content infringement by Copyscape