Ramco

• Oct 8th, 2006

 

Table space is the logical data units of a database. every database is divided into Database -> tablespace -> segments - > externs

in short (tablespace is a logical group of data files in a database)

Decode is the sql functions for the replacement of If- Then -else logic

and case is simillar to If- Then -else logic except that we can make logical comparision of columns involved in the case structures.

ex : select case snum when snum > 10 then 'High' when snum>5 then 'Low' end from sales..

ex : select decode(snum,10,'high',5,'low') from sales..

that is we cannot make logical comparision of columns in Decode() functions.

Vrushali

• Aug 9th, 2007

 

Tablespace : A tablespace is a logical structure on a Oracle database consisting of one or more datafiles. The objects are stored in a tablespace.

Clusters: When two or more tables have a requirements of a same column and data in that column also is the same then that column is clustered and it is shared by all the tables in which that column is defined. So when the data in that column is changed all the related tables are affected.

Decode: It is like a IF condition, in which based on the result i.e TRUE or FALSE the corresponding expression is executed or value returned.

Case: This is also a conditional structure but unlike decode here you can check for multiple conditions within 1 case statement