Databases
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Postsdbo
PO
 

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    <p>I think you are confusing the use of primary keys and constraints (business domain model) with the use of indexes (performance).</p> <p>A Foreign Key can influence an optimiser, and it is common to create an index on Foreign keys. </p> <p>In the SQL Server world, a Primary key is often confused with a Clustered index, because more often than than a surrogate key (think auto-increment identity column) is choosen as the Primary Key and Clustered Index.</p> <p>This article may be of interest: <a href="http://msdn.microsoft.com/en-us/magazine/cc163709.aspx" rel="nofollow noreferrer">DataSet and DataTable in ADO.NET 2.0</a>.</p> <p>In response to your comment:</p> <blockquote> <p><strong>Use a DataView for Repetitive Non-Primary Key Searches</strong> If you need to repetitively search by using non-primary key data, create a DataView that has a sort order. This creates an index that can be used to perform the search. This is best suited to repetitive searches because there is some cost to creating the index. </p> <p>The DataView object exposes the Find and FindRows methods so that you can query the data in the underlying DataTable. If you are only performing a single query, the processing that is required to create the index reduces the performance that is gained by using the index. </p> <p>When you create a DataView object, use the DataView constructor that takes the Sort, RowFilter, and RowStateFilter values as constructor arguments along with the underlying DataTable. Using the DataView constructor ensures that the index is built once. If you create an empty DataView and set the Sort, RowFilter, or RowStateFilter properties afterwards, the index is built at least two times.</p> </blockquote>
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    1. POHow do ADO.NET DataTable Constraints affect performance?
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    1. USMitch Wheat
    1. USMitch Wheat
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    1. COIs there a way to add an index to an ADO.NET DataTable that would give me an efficient lookup on those columns? I didn't see one, hence the UniqueConstraint, which in SQL Server would give me an implicit index. I just don't know if the same efficiency translates to .NET.
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      1. USSeibar
    2. COYou should benchmark it and see for yourself if it creates an improvement in your situation. The results may surprise you.
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      1. USJim Counts
    3. COBenchmarking is always a good idea.
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