How Can I Efficiently Query Entities with Composite Keys in Entity Framework?

Efficient query entity in Entity Framework

When using Entity Framework and the composite key, realize the same functions as simple Contains () query becomes more complicated. This article discusses various methods to solve this problem:

Try the use of key values ​​and use contains

Try to use the composite primary key value for direct connection or contains operations in Entity Framework. This is because this type of operation cannot be converted to SQL, because in this context, the meta -group is not regarded as the original value.

Use memory treatment

Another method is to use AsenmemeRable () to extract the database table data into the memory and use Linq to Objects to perform the necessary screening. However, for large tables, this solution is extremely low.

Use two contains statements (incorrect)

The use of a separate contains () statement for each composite primary key component can cause incorrect screening. This method will produce misleading results, because only one -matching entity is included in error.

Use the calculation value to perform a single contains query

The contains () query that is modified containing the calculation value containing the composite primary key component (e.g. Entity.id1 * Entity.id2). However, this solution is non -searchable, resulting in low performance.

Combined with contains and memory connections (solution 5)

The most scalable method is to combine contains and memory connections. This method uses preliminary contains () queries to reduce the result set, and then more accurate refinement through the memory connection.

Build query with OR clause (solution 6)

The predicate of the predicate like Linqkit allows the creation of an OR Zi sentence containing the combination of each composite main key value. Although this method may be suitable for small lists, its performance will decline for large lists.

Utilize (Solution 7)

Another method is to combine multiple queries of each composite main key value combination using Union. This solution may be effective for small to medium size lists.

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