crystal reports code 128 Temporary Tables Wrap-up in Objective-C

Drawer Data Matrix ECC200 in Objective-C Temporary Tables Wrap-up

Temporary Tables Wrap-up
Data Matrix 2d Barcode Maker In Objective-C
Using Barcode drawer for iPhone Control to generate, create Data Matrix 2d barcode image in iPhone applications.
www.OnBarcode.com
Printing Barcode In Objective-C
Using Barcode generation for iPhone Control to generate, create Barcode image in iPhone applications.
www.OnBarcode.com
Temporary tables can be useful in an application where you need to temporarily store a set of rows to be processed against other tables, for either a session or a transaction. They are not meant to be used as a means to take a single larger query and break it up into smaller result sets that would be combined back together (which seems to be the most popular use of temporary tables in other databases). In fact, you will find in almost all cases that a single query broken up into smaller temporary table queries performs more slowly in Oracle than the single query would have. I ve seen this behavior time and time again, when given the opportunity to rewrite the series of INSERTs into temporary tables as SELECTs in the form of one large query, the resulting single query executes much faster than the original multi-step process.
Encoding QR Code ISO/IEC18004 In Objective-C
Using Barcode maker for iPhone Control to generate, create Quick Response Code image in iPhone applications.
www.OnBarcode.com
EAN 128 Generator In Objective-C
Using Barcode creation for iPhone Control to generate, create EAN128 image in iPhone applications.
www.OnBarcode.com
CHAPTER 10 DATABASE TABLES
Drawing EAN13 In Objective-C
Using Barcode printer for iPhone Control to generate, create EAN13 image in iPhone applications.
www.OnBarcode.com
GS1 - 12 Generation In Objective-C
Using Barcode generation for iPhone Control to generate, create UPC Symbol image in iPhone applications.
www.OnBarcode.com
Temporary tables generate a minimum amount of redo, but they still generate some redo, and there is no way to disable that. The redo is generated for the rollback data, and in most typical uses it will be negligible. If you only INSERT and SELECT from temporary tables, the amount of redo generated will not be noticeable. Only if you DELETE or UPDATE a temporary table heavily will you see large amounts of redo generated. Statistics used by the CBO can be generated on a temporary table with care; however, a better guess set of statistics may be set on a temporary table using the DBMS_STATS package or dynamically collected by the optimizer at hard parse time using dynamic sampling.
Paint Barcode In Objective-C
Using Barcode creator for iPhone Control to generate, create Barcode image in iPhone applications.
www.OnBarcode.com
UPC - 8 Generator In Objective-C
Using Barcode creator for iPhone Control to generate, create EAN8 image in iPhone applications.
www.OnBarcode.com
Object Tables
DataMatrix Reader In VB.NET
Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Data Matrix Generation In None
Using Barcode maker for Excel Control to generate, create Data Matrix 2d barcode image in Microsoft Excel applications.
www.OnBarcode.com
We have already seen a partial example of an object table with nested tables. An object table is a table that is created based on a TYPE, not as a collection of columns. Normally, a CREATE TABLE statement would look like this: create table t ( x int, y date, z varchar2(25) ); An object table creation statement looks more like this: create table t of Some_Type; The attributes (columns) of T are derived from the definition of SOME_TYPE. Let s quickly look at an example involving a couple of types, and then review the resulting data structures: ops$tkyte@ORA11GR2> create or replace type address_type 2 as object 3 ( city varchar2(30), 4 street varchar2(30), 5 state varchar2(2), 6 zip number 7 ) 8 / Type created. ops$tkyte@ORA11GR2> create or replace type person_type 2 as object 3 ( name varchar2(30), 4 dob date, 5 home_address address_type, 6 work_address address_type 7 ) 8 / Type created. ops$tkyte@ORA11GR2> create table people of person_type 2 / Table created.
Painting UCC-128 In None
Using Barcode encoder for Font Control to generate, create GS1 128 image in Font applications.
www.OnBarcode.com
Scan Barcode In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
CHAPTER 10 DATABASE TABLES
ECC200 Creator In None
Using Barcode generator for Online Control to generate, create Data Matrix image in Online applications.
www.OnBarcode.com
Barcode Scanner In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
ops$tkyte@ORA11GR2> desc people Name Null ---------------------------------------- -------NAME DOB HOME_ADDRESS WORK_ADDRESS
Encoding QR Code In None
Using Barcode drawer for Online Control to generate, create QR Code JIS X 0510 image in Online applications.
www.OnBarcode.com
EAN / UCC - 13 Maker In None
Using Barcode creation for Office Word Control to generate, create European Article Number 13 image in Microsoft Word applications.
www.OnBarcode.com
Type ---------------------------VARCHAR2(30) DATE ADDRESS_TYPE ADDRESS_TYPE
Paint Code 39 Extended In None
Using Barcode encoder for Office Word Control to generate, create Code-39 image in Word applications.
www.OnBarcode.com
Generating Barcode In None
Using Barcode printer for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
In a nutshell, that s all there is to it. We create some type definitions, and then we can create tables of that type. The table appears to have four columns representing the four attributes of the PERSON_TYPE we created. We are at the point where we can now perform DML on the object table to create and query data: ops$tkyte@ORA11GR2> insert into people values ( 'Tom', '15-mar-1965', 2 address_type( 'Reston', '123 Main Street', 'Va', '45678' ), 3 address_type( 'Redwood', '1 Oracle Way', 'Ca', '23456' ) ); 1 row created. ops$tkyte%ORA11GR2> select name, dob, p.home_address Home, p.work_address work 2 from people p; NAME DOB HOME(CITY, STREET, STA ---- --------- ---------------------Tom 15-MAR-65 ADDRESS_TYPE('Reston', '123 Main Street', 'Va', 45678) WORK(CITY, STREET, STAT ----------------------ADDRESS_TYPE('Redwood', '1 Oracle Way', 'Ca', 23456)
Recognizing PDF417 In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
2D Barcode Maker In .NET Framework
Using Barcode maker for VS .NET Control to generate, create 2D image in Visual Studio .NET applications.
www.OnBarcode.com
ops$tkyte@ORA11GR2> select name, p.home_address.city from people p; NAME HOME_ADDRESS.CITY ----- -----------------------------Tom Reston We re starting to see some of the object syntax necessary to deal with object types. For example, in the INSERT statement we had to wrap the HOME_ADDRESS and WORK_ADDRESS with a CAST. We cast the scalar values to be of an ADDRESS_TYPE. Another way of saying this is that we create an ADDRESS_TYPE instance for that row by using the default constructor for the ADDRESS_TYPE object. Now, as far as the external face of the table is concerned, there are four columns in our table. By now, after seeing the hidden magic that took place for the nested tables, we can probably guess that there is something else going on. Oracle stores all object relational data in plain old relational tables at the end of the day, it is all in rows and columns. If we dig into the real data dictionary, we can see what this table really looks like: ops$tkyte@ORA11GR2> select name, segcollength 2 from sys.col$ 3 where obj# = ( select object_id 4 from user_objects 5 where object_name = 'PEOPLE' ) 6 /
Copyright © OnBarcode.com . All rights reserved.