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Update index.md #1877

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Oct 24, 2019
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Update index.md #1877

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2 changes: 1 addition & 1 deletion entity-framework/core/what-is-new/ef-core-3.0/index.md
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Expand Up @@ -53,7 +53,7 @@ See the [breaking changes documentation](xref:core/what-is-new/ef-core-3.0/break

### Single SQL statement per LINQ query

Another aspect of the design that changed significantly in 3.0 is that we now always generate a single SQL statement per LINQ query. In previous versions, we used to generate multiple SQL statements in certain cases, like to translate `Include()` calls on collection navigation properties and to translate queries that followed certain patterns with subqueries. Although this was in some cases convenient, and for `Include()` it even helped avoid sending redundant data over the wire, the implementation was complex, it resulted in some extremely inefficient behaviors (N+1 queries), and there was situations in which the data returned across multiple queries could be inconsistent.
Another aspect of the design that changed significantly in 3.0 is that we now always generate a single SQL statement per LINQ query. In previous versions, we used to generate multiple SQL statements in certain cases, translated `Include()` calls on collection navigation properties and translated queries that followed certain patterns with subqueries. Although this was in some cases convenient, and for `Include()` it even helped avoid sending redundant data over the wire, the implementation was complex, and it resulted in some extremely inefficient behaviors (N+1 queries). There were situations in which the data returned across multiple queries was potentially inconsistent.

Similarly to client evaluation, if EF Core 3.0 can't translate a LINQ query into a single SQL statement, it throws a runtime exception. But we made EF Core capable of translating many of the common patterns that used to generate multiple queries to a single query with JOINs.

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