Merge pull request #18013 from abpframework/article/ef-core-primitive-collections

Add `EF Core 8 Primitive collections` article

docs/en/Community-Articles/2023-10-28-EF-Core-8-Primitive-Collections/POST.md

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+# EF Core 8 Primitive collections
+
+What can we do when we want to store a list of primitive types? Before EF Core 8, there were two options:
+
+- Create a wrapper class and a related table, then add a foreign key linking each value to its owner of the collection.
+- Use [value converter](https://learn.microsoft.com/en-us/ef/core/modeling/value-conversions) to serialize-deserialize as JSON.
+
+The first option covers most scenarios if we need to add some additional properties to this type but let's say we're never gonna need this type additionality. 
+
+## Which collection types are supported ?
+
+EF Core has the capability to map the `IEnumerable<T>` public properties that have both a getter and a setter, with the `T` representing a primitive type
+
+```csharp
+public class PrimitiveCollections
+{
+    public IEnumerable<int> Ints { get; set; }
+    public ICollection<string> Strings { get; set; }
+    public ISet<DateTime> DateTimes { get; set; }
+    public IList<DateOnly> Dates { get; set; }
+    public uint[] UnsignedInts { get; set; }
+    public List<bool> Booleans { get; set; }
+    public List<Uri> Urls { get; set; }
+}
+```
+
+> Some generic arguments are not considered primitive on the database side, such as `uint` and `Uri`. However, these types are also considered as primitive because there are [built-in value converters](https://learn.microsoft.com/en-us/ef/core/modeling/value-conversions?tabs=data-annotations#built-in-converters).
+
+## Demo 
+
+In this sample, we have a `Car` class with a `Color` enum, and the `Car` class has a `Colors` property.
+
+```csharp
+public enum Color
+{
+    Black,
+    White,
+    Red,
+    Blue
+}
+
+public class Car
+{
+    public int Id { get; set; }
+    public string Brand { get; set; }
+    public string Model { get; set; }
+    public ISet<Color> Colors { get; set; } = new HashSet<Color>();
+
+    public Car(string brand, string model)
+    {
+        Brand = brand;
+        Model = model;
+    }
+}
+```
+
+When we want to list the cars if they have any of the specific colors.
+
+```csharp
+var colors = new HashSet<Color> { Color.Blue, Color.White };
+var cars = await context
+    .Cars
+    .Where(x=> x.Colors.Intersect(colors).Any())
+    .ToListAsync();
+```
+
+The SQL result looks like this; as you can see, it sends colors as parameters instead of adding them inline. It also uses the `json_each` function to deserialize on the database side.
+
+```sql
+SELECT "c"."Id", "c"."Brand", "c"."Colors", "c"."Model"
+      FROM "Cars" AS "c"
+      WHERE EXISTS (
+          SELECT 1
+          FROM (
+              SELECT "c0"."value"
+              FROM json_each("c"."Colors") AS "c0"
+              INTERSECT
+              SELECT "c1"."value"
+              FROM json_each(@__colors_0) AS "c1"
+          ) AS "t")
+
+```
+
+When we insert to the car table.
+
+```csharp
+var car = new Car("Maserati", "GranTurismo")
+{
+    Colors = new HashSet<Color>()
+    {
+        Color.Black,
+        Color.Blue
+    }
+};
+context.Cars.Add(car);
+await context.SaveChangesAsync();
+```
+
+The SQL statement looks like this, and as you can see, it automatically serializes into the Colors parameter as JSON.
+
+```sql
+ Executed DbCommand (0ms) [Parameters=
+ [@p0='Maserati' (Nullable = false) (Size = 8),
+  @p1='[0,3]' (Nullable = false) (Size = 5),
+  @p2='Flow' (Nullable = false) (Size = 4)
+ ], CommandType='Text', CommandTimeout='30']
+      INSERT INTO "Cars" ("Brand", "Colors", "Model")
+      VALUES (@p0, @p1, @p2)
+      RETURNING "Id";
+```
+## Conclusion
+
+We don't need to do anything if we just use a collection of primitive types. It serializes and deserializes them as JSON automatically. Additionally, it sends the primitive collection as a parameter to cache the query.
+
+## References
+
+- [EF Core 8 Primitive collections](https://learn.microsoft.com/en-us/ef/core/what-is-new/ef-core-8.0/whatsnew#primitive-collection-properties)
+- [.NET Data Community Standup - Collections of primitive values in EF Core](https://www.youtube.com/watch?v=AUS2OZjsA2I)