native barcode generator for crystal reports crack DATABASE TABLES in Objective-C

Make Data Matrix in Objective-C DATABASE TABLES

CHAPTER 10 DATABASE TABLES
Generating Data Matrix ECC200 In Objective-C
Using Barcode printer for iPhone Control to generate, create ECC200 image in iPhone applications.
www.OnBarcode.com
Barcode Maker In Objective-C
Using Barcode encoder for iPhone Control to generate, create Barcode image in iPhone applications.
www.OnBarcode.com
C_OBJ#_INTCOL# C_RG# C_TOID_VERSION#
UPC Code Drawer In Objective-C
Using Barcode generator for iPhone Control to generate, create Universal Product Code version A image in iPhone applications.
www.OnBarcode.com
Encode EAN-13 Supplement 5 In Objective-C
Using Barcode maker for iPhone Control to generate, create European Article Number 13 image in iPhone applications.
www.OnBarcode.com
C_TS# C_USER# SMON_SCN_TO_TIME_AUX 37 rows selected.
Encoding Code 128A In Objective-C
Using Barcode maker for iPhone Control to generate, create Code 128 Code Set B image in iPhone applications.
www.OnBarcode.com
Make EAN / UCC - 14 In Objective-C
Using Barcode generation for iPhone Control to generate, create EAN / UCC - 14 image in iPhone applications.
www.OnBarcode.com
OPQTYPE$ ICOLDEP$ VIEWTRCOL$ LIBRARY$ ASSEMBLY$ ATTRCOL$ TYPE_MISC$ COLTYPE$ LOB$ TAB$ CLU$ COL$ ICOL$ IND$ HISTGRM$ RGROUP$ RGCHILD$ PARAMETER$ RESULT$ METHOD$ ATTRIBUTE$ COLLECTION$ TYPE$ TS$ FET$ TSQ$ USER$ SMON_SCN_TIME
Drawing Barcode In Objective-C
Using Barcode generator for iPhone Control to generate, create Barcode image in iPhone applications.
www.OnBarcode.com
UPC - 8 Encoder In Objective-C
Using Barcode maker for iPhone Control to generate, create EAN-8 image in iPhone applications.
www.OnBarcode.com
As you can see, most of the object-related data is stored in a single cluster (the C_OBJ# cluster): 16 tables sharing the same block. It is mostly column-related information stored there, so all of the information about the set of columns of a table or index is stored physically on the same block. This makes sense, as when Oracle parses a query, it wants to have access to the data for all of the columns in the referenced table. If this data were spread all over the place, it would take a while to get it together. Here, it is on a single block typically and readily available. When would you use a cluster It is easier perhaps to describe when not to use one: If you anticipate the tables in the cluster will be modified heavily: You must be aware that an index cluster will have certain negative performance side effects on DML performance, INSERT statements in particular. It takes more work to manage the data in a cluster. The data has to be put away carefully, so it takes longer to put the data away (to insert it). If you need to perform full scans of tables in clusters: Instead of just having to full scan the data in your table, you have to full scan the data for (possibly) many tables. There is more data to scan through, so full scans will take longer. If you need to partition the tables: Tables in a cluster cannot be partitioned, nor can the cluster be partitioned. If you believe you will frequently need to TRUNCATE and load the table: Tables in clusters cannot be truncated. That is obvious since the cluster stores more than one table on a block, you must delete the rows in a cluster table.
Creating ECC200 In None
Using Barcode creation for Excel Control to generate, create Data Matrix 2d barcode image in Microsoft Excel applications.
www.OnBarcode.com
Decoding Data Matrix ECC200 In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
CHAPTER 10 DATABASE TABLES
PDF417 Printer In Visual Studio .NET
Using Barcode generator for Visual Studio .NET Control to generate, create PDF-417 2d barcode image in VS .NET applications.
www.OnBarcode.com
Scanning Barcode In Java
Using Barcode Control SDK for BIRT Control to generate, create, read, scan barcode image in Eclipse BIRT applications.
www.OnBarcode.com
So, if you have data that is mostly read (that does not mean never written ; it is perfectly OK to modify cluster tables) and read via indexes, either the cluster key index or other indexes you put on the tables in the cluster, and join this information together frequently, a cluster would be appropriate. Look for tables that are logically related and always used together, like the people who designed the Oracle data dictionary when they clustered all column-related information together.
UCC - 12 Encoder In None
Using Barcode creator for Online Control to generate, create UPC Code image in Online applications.
www.OnBarcode.com
Code-39 Generator In VS .NET
Using Barcode encoder for ASP.NET Control to generate, create Code 39 Full ASCII image in ASP.NET applications.
www.OnBarcode.com
Index Clustered Tables Wrap-up
Code 128 Decoder In C#
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Recognize USS Code 39 In C#.NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
Clustered tables give you the ability to physically prejoin data together. You use clusters to store related data from many tables on the same database block. Clusters can help read-intensive operations that always join data together or access related sets of data (e.g., everyone in department 10). Clustered tables reduce the number of blocks that Oracle must cache. Instead of keeping ten blocks for ten employees in the same department, Oracle will put them in one block and therefore increase the efficiency of your buffer cache. On the downside, unless you can calculate your SIZE parameter setting correctly, clusters may be inefficient with their space utilization and can tend to slow down DML-heavy operations.
Creating UCC-128 In Objective-C
Using Barcode printer for iPad Control to generate, create USS-128 image in iPad applications.
www.OnBarcode.com
EAN / UCC - 13 Encoder In Java
Using Barcode generator for Android Control to generate, create UCC.EAN - 128 image in Android applications.
www.OnBarcode.com
Hash Clustered Tables
Read Barcode In .NET Framework
Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Encoding Data Matrix In None
Using Barcode maker for Software Control to generate, create Data Matrix 2d barcode image in Software applications.
www.OnBarcode.com
Hash clustered tables are very similar in concept to the index clustered tables just described with one main exception: the cluster key index is replaced with a hash function. The data in the table is the index; there is no physical index. Oracle will take the key value for a row, hash it using either an internal function or one you supply, and use that to figure out where the data should be on disk. One side effect of using a hashing algorithm to locate data, however, is that you cannot range scan a table in a hash cluster without adding a conventional index to the table. In an index cluster, the query select * from emp where deptno between 10 and 20 would be able to make use of the cluster key index to find these rows. In a hash cluster, this query would result in a full table scan unless you had an index on the DEPTNO column. Only exact equality searches (including IN lists and subqueries) may be made on the hash key without using an index that supports range scans. In a perfect world, with nicely distributed hash key values and a hash function that distributes them evenly over all of the blocks allocated to the hash cluster, we can go straight from a query to the data with one I/O. In the real world, we will end up with more hash key values hashing to the same database block address than fit on that block. This will result in Oracle having to chain blocks together in a linked list to hold all of the rows that hash to this block. Now, when we need to retrieve the rows that match our hash key, we might have to visit more than one block. Like a hash table in a programming language, hash tables in the database have a fixed size. When you create the table, you must determine the number of hash keys your table will have, forever. That does not limit the amount of rows you can put in there. In Figure 10-9, we can see a graphical representation of a hash cluster with table EMP created in it. When the client issues a query that uses the hash cluster key in the predicate, Oracle will apply the hash function to determine which block the data should be in. It will then read that one block to find the data. If there have been many collisions, or the SIZE parameter to the CREATE CLUSTER was underestimated, Oracle will have allocated overflow blocks that are chained off the original block.
Copyright © OnBarcode.com . All rights reserved.