How to query the size of table footprint in db

Both Oracle and DB2 support partitioned tables, but we need to know what tables are appropriate for partitioning table technology, and Oracle's official recommendation is to use partitioned tables for more than 2G table.

Here's a summary of how you can get these size information in each DB:

Oracle 10G:

Queries the size of the space occupied by the current user's table and arranges by size in descending order:

Select segment_name,sum (bytes)/1024/1024 from User_extents Group by segment_name Order by Sum (bytes)/1024/1024

Query the size of the system tablespaces and arrange them in descending order of size (requires SYSDBA permissions):

Select tablespace_name,sum (bytes)/1024/1024 from Dba_segments Group by Tablespace_name Order by Sum (bytes)/1024/1024 Desc

This can also be seen in the OEMC, but if it is not installed, the SQL statement is more convenient.

In DB2:

Viewing the size of a table can be viewed in a graphical interface in the control center.

In SQL Server:

Perform statistics and view the table size for the specified table name:

EXEC sp_spaceused ' table name ', true;