Refactor data layer, add business layer

DataLayer/scripts/seed/procedures/USP_CreateUserVerification.sql

@@ -0,0 +1,31 @@
+CREATE OR ALTER PROCEDURE dbo.USP_CreateUserVerification
+AS
+BEGIN
+    SET NOCOUNT ON;
+    SET XACT_ABORT ON;
+
+    BEGIN TRANSACTION;
+
+    INSERT INTO dbo.UserVerification
+        (UserAccountId)
+    SELECT
+        ua.UserAccountID
+    FROM dbo.UserAccount AS ua
+    WHERE NOT EXISTS
+            (SELECT 1
+    FROM dbo.UserVerification AS uv
+    WHERE uv.UserAccountId = ua.UserAccountID);
+
+
+    IF (SELECT COUNT(*)
+    FROM dbo.UserVerification) 
+        != (SELECT COUNT(*)
+    FROM dbo.UserAccount)
+    BEGIN
+        RAISERROR('UserVerification count does not match UserAccount count after insertion.', 16, 1);
+        ROLLBACK TRANSACTION;
+        RETURN;
+    END
+
+    COMMIT TRANSACTION;
+END