Updated user defined types section (#798)

* Updated user defined types section

* Added detail to user-defined types.

* Removed specific user-defined types.

---------

Co-authored-by: rkac-bw <148072202+rkac-bw@users.noreply.github.com>

Author: mkincaid-bw

docs/contributing/code-style/sql.md

@@ -536,15 +536,17 @@ WHERE
 
 ### User defined types
 
-- **User Defined Type Name**: `[Schema].[TypeName]` (e.g., `[dbo].[GuidIdArray]`)
-  - The name should describe the type
+New user defined types should not be created. The following existing types may be used as
+table-valued parameters in stored procedures:
 
-```sql
-CREATE TYPE [dbo].[TypeName] AS TABLE
-(   [Column1] DATATYPE NOT NULL,
-    [Column2] DATATYPE NOT NULL
-);
-```
+- **`[dbo].[GuidIdArray]`** — a single-column table of `UNIQUEIDENTIFIER` values. Use when passing a
+  list of IDs to a stored procedure (e.g., bulk reads or deletes).
+
+- **`[dbo].[TwoGuidIdArray]`** — a two-column table of `UNIQUEIDENTIFIER` pairs (`Id1`, `Id2`). Use
+  when an operation requires two related IDs per row (e.g., user ID + organization ID).
+
+- **`[dbo].[EmailArray]`** — a single-column table of `NVARCHAR(256)` email addresses. Use when
+  passing a list of emails to a stored procedure.
 
 ### Indexes