Index information verification

1. Use tools to verify index information. For example, Oracle databases can use PL/SQL.

2. The indexes are verified by the data dictionary user_indexes and user_ind_columns.
Select IC. index_name, IC. column_name, IC. column_position col_pos, ix. uniqueness
From user_indexes IX, user_ind_columns IC
Where IC. index_name = IX. index_name
And IC. table_name = 'G _ chkunit'
And IC. index_name = 'idx _ g_chkunit_org ';

3. Verify the index based on the data dictionary dba_ind_columns.
Select a. index_name, A. column_name, A. column_position, A. column_length, A. char_length, A. Descend
From dba_ind_columns
Where a. table_owner = 'sgpm'
And a. table_name = 'G _ chkunit'
And a. index_name = 'idx _ g_chkunit_org ';

4. Use queries and execution plans to verify index information
Select rownum, org_no from g_chkunit where org_no <'000000' order by org_no ASC;

Execution result: rownum is ordered;

The execution plan shows that the query is indexed, so the query is sorted first and rownum is assigned, so the execution result is ordered.