09-19-2007 9:34 AM
Hi Gurus,
What is the difference between cluster table and a view ?
Thanks in advance,
Sriram Tangirala.
09-19-2007 9:38 AM
hi
view is a virtual table table u can use in select statement to increase performance of the select statement
view contains data at run time but not in the case of cluster table
cluster table is a structure which exists in database table clusters has to be insert in cluster table it has one to many relation ship
reward for use ful points
regards
Nagesh.Paruchuri
09-19-2007 9:36 AM
In view no actual data get stored but it will just join two tables
Where cluster tables are combination of two or more database tables having actual data
Rewards if useful.............
Minal
09-19-2007 9:38 AM
Hi,
Cluster tables are combination of two or more database tables...
Whereas View is just to visualise the data for two or more tables...
Cluster tables occupy memory whereas View doesnt occupy any memory...
Please reward if useful....
thanks and regards,
shori...
09-19-2007 9:36 AM
Cluster table
Cluster tables contain continuous text, for example, documentation.
Several cluster tables can be combined to form a table cluster. Several
logical lines of different tables are combined to form a physical record
in this table type. This permits object-by-object storage or
object-by-object access. In order to combine tables in clusters, at
least parts of the keys must agree. Several cluster tables are stored in
one corresponding table on the database.
Tables : These are the data holders we can store the data inside.
views : these are virtual tables we are going to show data with respect to tables in views .
VIEWS we can select the data which is already combined at the dictionary level. This is done in SE11
View - It is usually created with the intention to reduce the lead time for fetching thedta. The view can be a single table or based on join.
View as such does not hold any data. The SQL statement used to create view is compiled and avaialble in the DB. Hence data fetch will be fast.
Database View - To club more than one table
Projection View - To hide fields in one table
Maintanance View - To maintain database records in table
Help View - To provide help for a fields (Same functionality as Search help. This is outdated)
View are improves perfromance in the following aspects
1. If you want to use more than two table in 'JOIN' condition better to use Views . It will improves performance of a program
2. If you want to use mutiple FOR ALL ENTRIES clause, better to club all SELECT statement in a view.
note:
1.Views does not contain data in it. It fetches data from the database only depending on the condition ...
2.Views are part of data dictionary. They are a window to view the data in database
3.views can be used to give security to data. users can be allowed to view only basic data only
Regards
Vasu
09-19-2007 9:37 AM
Hello Sriram,
<b>Cluster Table:</b>
Cluster tables are logical tables that must be assigned to a table cluster when they are defined. Cluster tables can be used to strore control data. They can also be used to store temporary data or texts, such as documentation.
A clustered and a pooled table cannot be read from outside SAP because certain data are clustered and pooled in one field.
<b>View :</b>
database view is a logical defination of table it does not exists physically in the database. it gets its value from the database depending on its defination. and joins used.
databse view - it is a window to a database table.
Views are nothing but the Inner join on tables. They do not contain data physically, They contain data only at run time which they derive from the underneath tables.
To get clear idea on cluster table check
http://help.sap.com/saphelp_nw04/helpdata/en/cf/21f083446011d189700000e8322d00/content.htm
<b>Reward Points If Useful</b>
Regards, Srikanth
09-19-2007 9:38 AM
hi
view is a virtual table table u can use in select statement to increase performance of the select statement
view contains data at run time but not in the case of cluster table
cluster table is a structure which exists in database table clusters has to be insert in cluster table it has one to many relation ship
reward for use ful points
regards
Nagesh.Paruchuri
09-19-2007 9:38 AM
Hi,
<b>VIEW</b> is basically a JOIN on one or more tables and does not store the data instead uses the JOIN to fetch the data, so does not occupy any memory in the database.
Where as <b>Cluster table</b> is a kind of table where Many ABAP DDIC tables are mapped to One Database table. And the data is stored in archive format. So they occupy the memory in the database.
<b>Cluster table</b> is a database table defined in the ABAP Dictionary, whose version on the database is not only assigned to one table defined in the ABAP Dictionary. Several cluster tables are assigned to a table cluster in the database. The intersection of the key fields of the cluster tables forms the primary key of the table cluster. The other columns of the cluster tables are stored in compressed form in a single column VARDATA of the table cluster. You can access cluster tables only via Open SQL, and only without using joins.
<b>View</b>
Grouping of columns in one or more database tables according to application-specific criteria. In an ABAP-based SAP system, views are defined in the ABAP Dictionary and can be referenced as data types like flat structures. Views can be used like database tables in read Open SQL statements.
Regards,
Sesh
09-19-2007 9:43 AM
culster tablescontains documentation of the fields of the tables where as using views we able to see the output of the tables using database view or projection view , but primary key shoud be same when we want to see the output of two or more tables
09-19-2007 9:47 AM
CLUSTER TABLE: The data from several tables is stored together in a table pool or table cluster. Tables assigned to a table pool or table cluster are referred to as pooled tables or cluster tables.
VIEW : Physically it don't have data during run time it picks data from various tables based on join conditions.
Regards,
Sairam