Logical Storage in DB2 and Its Real Usage

In DB2, the must-know key point is logical storage. When I asked DB2 developers they were totally confused about the concept of logical storage. There are two kinds of storage in any RDBMS. One is physical and the other one is logical.

Logical Storage in DB2

Physical storage –> It is purely physical. On top of the physical, you will have logical storage.

Table storage

The final user will read from logical storage. Here’s sample query

Create table tablename
(various column names and attributes)
[in tablespace-name]
[Index in tablespace-name]

In the above SQL query both the Table and Index are defined in the same table space. So here table space is equal to logical storage.

What kind of controls do you have on tablespaces?

Yes, you need to have access to do any operation on the tables mentioned in the table space. You already know right?…admin has to give access. Any access… DBA is final here.

There are essentially three types of tablespaces you can declare a table to use during its creation. First, you can nominate in which regular tablespace the normal data for a table is stored.

You can optionally nominate a separate regular tablespace in which all the indexes for a table will be placed. Finally, you can allocate a large tablespace for housing the large objects of a table.

You can find more information in the above video on how to manage table-spaces.


Author: Srini

Experienced software developer. Skills in Development, Coding, Testing and Debugging. Good Data analytic skills (Data Warehousing and BI). Also skills in Mainframe.