crystal reports code 128 font INDEXES in Objective-C

Painting Data Matrix 2d barcode in Objective-C INDEXES

CHAPTER 11 INDEXES
ECC200 Maker In Objective-C
Using Barcode generation for iPhone Control to generate, create ECC200 image in iPhone applications.
www.OnBarcode.com
Encoding USS-128 In Objective-C
Using Barcode generation for iPhone Control to generate, create EAN 128 image in iPhone applications.
www.OnBarcode.com
we get the expected INDEX UNIQUE SCAN, and we can see the function is not being applied. You should always avoid implicit conversions anyway. Always compare apples to apples and oranges to oranges. Another case where this comes up frequently is with dates. We try to query -- find all records for today select * from t where trunc(date_col) = trunc(sysdate); and discover that the index on DATE_COL will not be used. We can either index the TRUNC(DATE_COL) or, perhaps more easily, query using range comparison operators. The following demonstrates the use of greater than and less than on a date. Once we realize that the condition TRUNC(DATE_COL) = TRUNC(SYSDATE) is the same as the condition select * from t where date_col >= trunc(sysdate) and date_col < trunc(sysdate+1) this moves all of the functions to the right-hand side of the equation, allowing us to use the index on DATE_COL (and it has the same exact effect as WHERE TRUNC(DATE_COL) = TRUNC(SYSDATE)). If possible, you should always remove the functions from database columns when they are in the predicate. Not only will doing so allow for more indexes to be considered for use, but it will also reduce the amount of processing the database needs to do. In the preceding case, when we used where date_col >= trunc(sysdate) and date_col < trunc(sysdate+1) the TRUNC values are computed once for the query, and then an index could be used to find just the qualifying values. When we used TRUNC(DATE_COL) = TRUNC(SYSDATE), the TRUNC(DATE_COL) had to be evaluated once per row for every row in the entire table (no indexes).
Generating Code 128 Code Set A In Objective-C
Using Barcode drawer for iPhone Control to generate, create Code 128 image in iPhone applications.
www.OnBarcode.com
Generating Quick Response Code In Objective-C
Using Barcode generator for iPhone Control to generate, create QR Code 2d barcode image in iPhone applications.
www.OnBarcode.com
Case 5
Encoding Barcode In Objective-C
Using Barcode encoder for iPhone Control to generate, create Barcode image in iPhone applications.
www.OnBarcode.com
Print UPC Symbol In Objective-C
Using Barcode generation for iPhone Control to generate, create GTIN - 12 image in iPhone applications.
www.OnBarcode.com
The index, if used, would actually be slower. I see this often people assume that, of course, an index will always make a query go faster. So, they set up a small table, analyze it, and find that the optimizer doesn t use the index. The optimizer is doing exactly the right thing in this case. Oracle (under the CBO) will use an index only when it makes sense to do so. Consider this example: ops$tkyte@ORA11GR2> create table t 2 ( x, y , primary key (x) ) 3 as 4 select rownum x, object_name 5 from all_objects 6 / Table created. ops$tkyte@ORA11GR2> begin 2 dbms_stats.gather_table_stats 3 ( user, 'T', cascade=>true ); 4 end; 5 / PL/SQL procedure successfully completed.
Make Barcode In Objective-C
Using Barcode generator for iPhone Control to generate, create Barcode image in iPhone applications.
www.OnBarcode.com
Encode UPCE In Objective-C
Using Barcode drawer for iPhone Control to generate, create UCC - 12 image in iPhone applications.
www.OnBarcode.com
CHAPTER 11 INDEXES
ECC200 Encoder In Visual C#.NET
Using Barcode generator for .NET Control to generate, create ECC200 image in Visual Studio .NET applications.
www.OnBarcode.com
ECC200 Generator In Java
Using Barcode encoder for Java Control to generate, create Data Matrix 2d barcode image in Java applications.
www.OnBarcode.com
If we run a query that needs a relatively small percentage of the table, as follows ops$tkyte@ORA11GR2> set autotrace on explain ops$tkyte@ORA11GR2> select count(y) from t where x < 50; COUNT(Y) ---------49 Execution Plan ---------------------------------------------------------0 SELECT STATEMENT Optimizer=ALL_ROWS (Cost=3 Card=1 Bytes=28) 1 0 SORT (AGGREGATE) 2 1 TABLE ACCESS (BY INDEX ROWID) OF 'T' (TABLE) (Cost=3 Card=41 Bytes=1148) 3 2 INDEX (RANGE SCAN) OF 'SYS_C009167' (INDEX (UNIQUE)) (Cost=2 Card=41) it will happily use the index; however, we ll find that when the estimated number of rows to be retrieved via the index crosses a threshold (which varies depending on various optimizer settings, physical statistics, and so on), we ll start to observe a full table scan ops$tkyte@ORA11GR2> select count(y) from t where x < 15000; COUNT(Y) ---------14999 Execution Plan ---------------------------------------------------------0 SELECT STATEMENT Optimizer=ALL_ROWS (Cost=57 Card=1 Bytes=28) 1 0 SORT (AGGREGATE) 2 1 TABLE ACCESS (FULL) OF 'T' (TABLE) (Cost=57 Card=14994 Bytes=419832) This example shows the optimizer won t always use an index and, in fact, it makes the right choice in skipping indexes. While tuning your queries, if you discover that an index isn t used when you think it ought to be, don t just force it to be used test and prove first that the index is indeed faster (via elapsed and I/O counts) before overruling the CBO. Reason it out.
Data Matrix Generator In None
Using Barcode creator for Word Control to generate, create DataMatrix image in Office Word applications.
www.OnBarcode.com
UPC-A Supplement 2 Encoder In Java
Using Barcode maker for Java Control to generate, create UPC-A Supplement 5 image in Java applications.
www.OnBarcode.com
Data Matrix 2d Barcode Maker In Java
Using Barcode generator for Java Control to generate, create DataMatrix image in Java applications.
www.OnBarcode.com
Generating USS Code 128 In None
Using Barcode maker for Font Control to generate, create Code 128 Code Set C image in Font applications.
www.OnBarcode.com
EAN13 Scanner In .NET Framework
Using Barcode scanner for .NET framework Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Make Barcode In VS .NET
Using Barcode printer for Visual Studio .NET Control to generate, create Barcode image in VS .NET applications.
www.OnBarcode.com
Data Matrix 2d Barcode Encoder In Visual C#.NET
Using Barcode creation for .NET Control to generate, create ECC200 image in .NET applications.
www.OnBarcode.com
Printing Code 39 In Java
Using Barcode generator for BIRT Control to generate, create Code 39 Extended image in BIRT reports applications.
www.OnBarcode.com
Barcode Drawer In VS .NET
Using Barcode generation for .NET framework Control to generate, create Barcode image in .NET framework applications.
www.OnBarcode.com
Barcode Encoder In Java
Using Barcode creation for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.