tag:blogger.com,1999:blog-4516533711330247058.post4388675015947546937..comments2024-03-28T07:32:09.246-07:00Comments on Robert's Db2 blog: DB2 10 for z/OS: New Options for Trimming and Upgrading IndexesRoberthttp://www.blogger.com/profile/02058625981006623480noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-4516533711330247058.post-89704178496061468862014-08-28T07:06:46.382-07:002014-08-28T07:06:46.382-07:00I'm not sure what you mean by the term "h...I'm not sure what you mean by the term "hash index." In a DB2 for z/OS environment, there are no "hash" indexes. There can be hash-organized tables, but indexes on these table are regular DB2 b-tree indexes. There is a hash overflow index on a hash-organized table (it's created by DB2), but this index is only used to speed access to rows that get stored in the overflow area of a table space holding a hash-organized table (rows that couldn't be placed in the target page as determined by the hash of the row's hash key value).<br /><br />RobertRoberthttps://www.blogger.com/profile/02058625981006623480noreply@blogger.comtag:blogger.com,1999:blog-4516533711330247058.post-67483545539328724902014-08-27T09:23:40.547-07:002014-08-27T09:23:40.547-07:00answered my own question:
QUERY MESSAGES: ...answered my own question: <br /><br />QUERY MESSAGES: <br />THE STATEMENT COULD NOT BE PROCESSED BECAUSE ONE OR MORE IMPLICITLY CREATED<br />OBJECTS ARE INVOLVED 5. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4516533711330247058.post-61716851214728395802014-08-27T08:51:08.077-07:002014-08-27T08:51:08.077-07:00do you know if you can use include with a hash ind...do you know if you can use include with a hash index?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4516533711330247058.post-77765178187710067902013-08-25T22:13:18.934-07:002013-08-25T22:13:18.934-07:00You can't specify ASC or DESC for INCLUDEd col...You can't specify ASC or DESC for INCLUDEd columns because that specification wouldn't change anything. Think about it. Columns can be INCLUDEd only for a unique index. The unique key values will be in their specified sequence (ASC or DESC), and for that reason ASC or DESC for INCLUDED columns is meaningless. Consider a unique index, on COL1, COL2 of a 4-row table, with these key values:<br />A1<br />B2<br />C3<br />D4<br /><br />Now, suppose you want to INCLUDE column COL3 in this unique index. Suppose the value of COL3 in the row with unique key value A1 is X, and is Y for the row with unique key value B2, and X again for the row with unique key value C3, and Y again for the row with unique key value D4. Remember, the INCLUDEd column is "just along for the ride" with the unique key - it does not affect the order of the unique key values. With COL3 included in the index, you get these key values (and I put the INCLUDEd column key value in parentheses for each):<br />A1(X)<br />B2(Y)<br />C3(X)<br />D4(Y)<br /><br />Again, order of INCLUDEd columns is determined by the order of the index's unique key, BECAUSE that key is unique. If the "base" (i.e., non-INCLUDE) key were non-unique (and it can't be - INCLUDE can only be specified for a unique index), ASC or DESC for the INCLUDEd columns would be meaningful.<br /><br />Hope this helps.<br /><br />RobertRoberthttps://www.blogger.com/profile/02058625981006623480noreply@blogger.comtag:blogger.com,1999:blog-4516533711330247058.post-1965221548870425142013-08-23T01:40:28.311-07:002013-08-23T01:40:28.311-07:00Hi Rob
The INCLUDE feature on the index i tried a...Hi Rob<br /><br />The INCLUDE feature on the index i tried and the INCLUDED columns are taking the order of the last column that exist on the index. why can't i specify ASC/DESC on my INCLUDE?Anonymousnoreply@blogger.com