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When do you design an index in a database?
When you design an index, consider the following database guidelines: Large numbers of indexes on a table affect the performance of INSERT, UPDATE, DELETE, and MERGE statements because all indexes must be adjusted appropriately as data in the table changes.
Which is better clustered or nonclustered indexes?
Alternatively, clustered and nonclustered indexes can use a partition scheme across multiple filegroups. Partitioning makes large tables or indexes more manageable by letting you access or manage subsets of data quickly and efficiently, while maintaining the integrity of the overall collection.
How are filtered indexes different from indexed views?
Filtered indexes can be non-unique, whereas indexed views must be unique. Filtered indexes are defined on one table and only support simple comparison operators. If you need a filter expression that references multiple tables or has complex logic, you should create a view.
Can a composite model combine two directquery models?
You want to combine a DirectQuery model with additional data, which must be imported into the model. Imported data can be loaded from a different data source, or from calculated tables. You want to combine two or more DirectQuery data sources into a single model. Composite models cannot combine connections to external analytic databases.
When do clustered indexes need to be created?
Clustered indexes do not have to be explicitly declared. Created when the table is created. Use the primary key sorted in ascending order. The clustered index will be automatically created when the primary key is defined: Once filled in, that table would look something like this:
How is the location of an index determined?
Determine the optimal storage location for the index. A nonclustered index can be stored in the same filegroup as the underlying table, or on a different filegroup. The storage location of indexes can improve query performance by increasing disk I/O performance.
How is the primary index maintained in Couchbase?
The primary index is simply the index on the document key on the whole bucket. The Couchbase data layer enforces the uniqueness constraint on the document key. The primary index, like every other index in Couchbase, is maintained asynchronously. You set the recency of the data by setting the consistency level for your query.