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Message Posted: Tue, 11 Mar 2003 @ 19:50:56 GMT


     
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Subj:   Re: Teradata DBC Views
 
From:   Dieter Nöth

Anomy Anom wrote:

  How Teradata manage Value ordered with more than one column index in DBC views? How it link orderby column of value ordered index with other index values in dbc.  


That info is stored in the table header on each AMP.


  if we check in the DBC.indices view it show the index column with index_type "V" but main problem is that when you use more than one columns in the index. You not able to find which column is used in order by clause of value ordered index.  


create index (foo, bar) order by values(bar) on table foobar;

There are three rows added in dbc.indices for that index: Two for columns foo and bar and one for the ordering column. They're stored with different index numbers, eg. x and x+4, but i don't know if this x+4 will always be true. IndexType for the index is 'V' and IndexType for the ordering column is 'I'.

e.g.
TableName IndexNumber IndexType ColumnName ColumnPosition
foobar       20          V         foo        1
foobar       20          V         bar        2
foobar       24          I         bar        1

Dieter



     
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