database-indexes

Are all the indexes in SQL Server B Tree? Surely primary keys and foreign should be hash based indexes? Not all indexes in SQL Server are B-tree indexes (SQL Server 2012 added columnstore indexes which are a bit different), but there is no such thing as a hash-based index there (yet). Here's a pretty straight forward article explaining that all indices are b tree indices in SQL Server: http://msdn.microsoft.com/en-us/library/ms177443(v=sql.105).aspx I think if you want to get more into the nitty gritty of specific RDBMS' implementations, you could try posting to http://dba.stackexchange.com 来源

When I run update_indexes on Google Datastore I get the message below. It is telling me to determine which indexes are in error by looking at the GUI, then delete these indexes. I have 51 erroneous indexes out of 200, and copying them out of the GUI is not feasible. (Edit: By laboriously removing and adding indexes from the datastore-indexes.xml, we identified the one problematic index.) Good devops procedure demands that we do this sort of thing automatically. How does one determine which indexes are in error programmatically? (Python, bash, or even Java are OK.) Cannot build indexes that are

I need constraints created in the following manner: CONSTRAINT [IX_Unique_1] UNIQUE NONCLUSTERED ( [Ordering] ASC, [Description] ASC ), CONSTRAINT [IX_Unique_2] UNIQUE NONCLUSTERED ( [Description] ASC ) I have the following nHibernate mapping: <property name="Description" column="Description" type="String" unique-key="IX_Seed_Template_Fields_Result" /> <property name="Ordering" column="Ordering" type="Int32" unique-key="IX_Seed_Template_Fields_Result" /> So how can I add a separate unique constraint just for the Description column? If you don't care about the index names in the database, you