crystal reports 2d barcode generator INDEXES in Font

Generating Data Matrix 2d barcode in Font INDEXES

CHAPTER 11 INDEXES
ECC200 Maker In None
Using Barcode generator for Font Control to generate, create Data Matrix 2d barcode image in Font applications.
www.OnBarcode.com
Make Barcode In None
Using Barcode encoder for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Execution Plan ---------------------------------------------------------0 SELECT STATEMENT Optimizer=ALL_ROWS (Cost=1 Card=1 Bytes=13) 1 0 TABLE ACCESS (BY INDEX ROWID) OF 'T' (TABLE) (Cost=1 Card=1 Bytes=13) 2 1 INDEX (RANGE SCAN) OF 'T_IDX' (INDEX) (Cost=1 Card=1) This is because the database is now not only rewriting the function in the CREATE INDEX, but also in the query itself, so they match. The workaround in prior releases is to do one of the following: Use DECODE instead of CASE, as DECODE is not rewritten and what you see is what you get. Use the searched CASE syntax in the first place (anticipate the optimization that will take place). But in any situation where your function-based index is not getting used and you cannot see any good reason why it should not be, check out USER_IND_EXPRESSIONS to verify that you are using the correct function.
QR-Code Creator In None
Using Barcode generation for Font Control to generate, create QR Code JIS X 0510 image in Font applications.
www.OnBarcode.com
Data Matrix ECC200 Drawer In None
Using Barcode generator for Font Control to generate, create Data Matrix image in Font applications.
www.OnBarcode.com
Caveat Regarding ORA-01743
UPC Code Maker In None
Using Barcode generator for Font Control to generate, create UPC-A Supplement 2 image in Font applications.
www.OnBarcode.com
Encoding EAN 13 In None
Using Barcode generator for Font Control to generate, create EAN13 image in Font applications.
www.OnBarcode.com
One quirk I have noticed with function-based indexes is that if you create one on the built-in function TO_DATE, it will not succeed in some cases, for example: ops$tkyte@ORA10GR1> create table t ( year varchar2(4) ); Table created. ops$tkyte@ORA10GR1> create index t_idx on t( to_date(year,'YYYY') ); create index t_idx on t( to_date(year,'YYYY') ) * ERROR at line 1: ORA-01743: only pure functions can be indexed This seems strange, since we can sometimes create a function using TO_DATE, for example: ops$tkyte@ORA10GR1> create index t_idx on t( to_date('01'||year,'MMYYYY') ); Index created. The error message that accompanies this isn t too illuminating either: ops$tkyte@ORA10GR1> !oerr ora 1743 01743, 00000, "only pure functions can be indexed" // *Cause: The indexed function uses SYSDATE or the user environment. // *Action: PL/SQL functions must be pure (RNDS, RNPS, WNDS, WNPS). SQL // expressions must not use SYSDATE, USER, USERENV(), or anything // else dependent on the session state. NLS-dependent functions // are OK. We are not using SYSDATE. We are not using the user environment (or are we ). No PL/SQL functions are used, and nothing about the session state is involved. The trick lies in the format we used: YYYY. That format, given the same exact inputs, will return different , anytime in the month of May
ANSI/AIM Code 128 Drawer In None
Using Barcode creator for Font Control to generate, create USS Code 128 image in Font applications.
www.OnBarcode.com
ISBN - 10 Drawer In None
Using Barcode printer for Font Control to generate, create ISBN - 13 image in Font applications.
www.OnBarcode.com
CHAPTER 11 INDEXES
Data Matrix 2d Barcode Generator In Java
Using Barcode encoder for Java Control to generate, create DataMatrix image in Java applications.
www.OnBarcode.com
Data Matrix ECC200 Drawer In .NET
Using Barcode maker for Visual Studio .NET Control to generate, create Data Matrix image in .NET applications.
www.OnBarcode.com
ops$tkyte@ORA10GR1> select to_char( to_date('2005','YYYY'), 2 'DD-Mon-YYYY HH24:MI:SS' ) 3 from dual; TO_CHAR(TO_DATE('200 -------------------01-May-2005 00:00:00 the YYYY format will return May 1, in June it will return June 1, and so on. It turns out that TO_DATE, when used with YYYY, is not deterministic! That is why the index cannot be created: it would only work correctly in the month you created it in (or insert/updated a row in). So, it is due to the user environment, which includes the current date itself. To use TO_DATE in a function-based index, you must use a date format that is unambiguous and deterministic regardless of what day it is currently.
Barcode Encoder In Java
Using Barcode generation for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
Generate Barcode In Java
Using Barcode drawer for BIRT reports Control to generate, create Barcode image in BIRT applications.
www.OnBarcode.com
Function-Based Indexes Wrap-Up
PDF417 Creator In Java
Using Barcode generator for Java Control to generate, create PDF417 image in Java applications.
www.OnBarcode.com
Barcode Reader In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Function-based indexes are easy to use and implement, and they provide immediate value. They can be used to speed up existing applications without changing any of their logic or queries. Many orders of magnitude improvement may be observed. You can use them to precompute complex values without using a trigger. Additionally, the optimizer can estimate selectivity more accurately if the expressions are materialized in a function-based index. You can use function-based indexes to selectively index only rows of interest as demonstrated earlier with the PROCESSED_FLAG example. You can, in effect, index a WHERE clause using that technique. Lastly, we explored how to use function-based indexes to implement a certain kind of integrity constraint: selective uniqueness (e.g., The fields X,Y, and Z must be unique when some condition is true ). Function-based indexes will affect the performance of inserts and updates. Whether or not that warning is relevant to you is something you must decide. If you insert and very infrequently query the data, this might not be an appropriate feature for you. On the other hand, keep in mind that you typically insert a row once and you query it thousands of times. The performance hit on the insert (which your individual end user will probably never notice) may be offset many thousands of times by speeding up the queries. In general, the pros heavily outweigh any of the cons in this case.
Making Barcode In Visual Studio .NET
Using Barcode generator for .NET Control to generate, create Barcode image in Visual Studio .NET applications.
www.OnBarcode.com
UPC-A Supplement 5 Recognizer In VB.NET
Using Barcode reader for .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
Draw UCC.EAN - 128 In .NET Framework
Using Barcode drawer for ASP.NET Control to generate, create UCC.EAN - 128 image in ASP.NET applications.
www.OnBarcode.com
Code 128 Code Set B Printer In VS .NET
Using Barcode maker for Visual Studio .NET Control to generate, create USS Code 128 image in .NET applications.
www.OnBarcode.com
GTIN - 128 Drawer In Java
Using Barcode creation for Android Control to generate, create USS-128 image in Android applications.
www.OnBarcode.com
Encode Barcode In None
Using Barcode creation for Online Control to generate, create Barcode image in Online applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.