separate the concepts of UserDefinedItem being updated in memory vs successful persistence

DataLayer/EfClasses/UserDefinedItem.cs

@@ -136,6 +136,7 @@ namespace DataLayer
         #endregion
         /// <summary>
         /// Occurs when <see cref="Tags"/>, <see cref="BookStatus"/>, or <see cref="PdfStatus"/> values change.
+        /// This signals the change of the in-memory value; it does not ensure that the new value has been persisted.
         /// </summary>
         public static event EventHandler<string> ItemChanged;
         public override string ToString() => $"{Book} {Rating} {Tags}";

DataLayer/_HowTo- EF Core.txt

@@ -1,57 +0,0 @@
-FOR QUICK MIGRATION INSTRUCTIONS:
-_DB_NOTES.txt
-
-
-HOW TO CREATE: EF CORE PROJECT
-==============================
-example is for sqlite but the same works with MsSql
-
-
-nuget
-Microsoft.EntityFrameworkCore.Tools (needed for using Package Manager Console)
-Microsoft.EntityFrameworkCore.Sqlite
-
-MIGRATIONS
-  require core, not standard
-  this can be a problem b/c standard and framework can only reference standard, not core
-TO USE MIGRATIONS (core and/or standard)
-  add to csproj
-    <PropertyGroup>
-      <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles>
-    </PropertyGroup>
-TO USE MIGRATIONS AS *BOTH* CORE AND STANDARD
-  edit csproj
-    pluralize this xml tag
-      from: TargetFramework
-      to: TargetFrameworks
-    inside of TargetFrameworks
-      from: netstandard2.1
-      to: netcoreapp3.1;netstandard2.1
-
-run. error
-SQLite Error 1: 'no such table: Blogs'.
-
-set project "Set as StartUp Project"
-
-Tools >> Nuget Package Manager >> Package Manager Console
-default project: Examples\SQLite_NETCore2_0
-
-PM> add-migration InitialCreate
-PM> Update-Database
-
-if add-migration xyz throws and error, don't take the error msg at face value. try again with add-migration xyz -verbose
-
-new sqlite .db file created: Copy always/Copy if newer
-or copy .db file to destination
-
-relative:
-   optionsBuilder.UseSqlite("Data Source=blogging.db");
-absolute  (use fwd slashes):
-   optionsBuilder.UseSqlite("Data Source=C:/foo/bar/blogging.db");
-
-
-REFERENCE ARTICLES
-------------------
-https://docs.microsoft.com/en-us/ef/core/get-started/netcore/new-db-sqlite
-https://carlos.mendible.com/2016/07/11/step-by-step-dotnet-core-and-entity-framework-core/
-https://www.benday.com/2017/12/19/ef-core-2-0-migrations-without-hard-coded-connection-strings/