Add option to persist enum names

Dapper/SqlMapper.Settings.cs

@@ -99,6 +99,11 @@ public static void SetDefaults()
             /// instead of the original name; for most scenarios, this is ignored since the name is redundant, but "snowflake" requires this.
             /// </summary>
             public static bool UseIncrementalPseudoPositionalParameterNames { get; set; }
+
+            /// <summary>
+            /// Whether to persist an enum by its name (<see cref="Enum.ToString()"/>) instead of by its underlying numeric value.
+            /// </summary>
+            public static bool PersistEnumsByName { get; set; }
         }
     }
 }

Dapper/SqlMapper.cs

@@ -369,7 +369,10 @@ public static void SetDbType(IDataParameter parameter, object value)
             if (nullUnderlyingType != null) type = nullUnderlyingType;
             if (type.IsEnum && !typeMap.ContainsKey(type))
             {
-                type = Enum.GetUnderlyingType(type);
+                if (Settings.PersistEnumsByName)
+                    type = typeof(string);
+                else
+                    type = Enum.GetUnderlyingType(type);
             }
             if (typeMap.TryGetValue(type, out var dbType))
             {
@@ -2247,6 +2250,9 @@ public static object SanitizeParameterValue(object value)
             if (value == null) return DBNull.Value;
             if (value is Enum)
             {
+                if (Settings.PersistEnumsByName)
+                    return value.ToString();
+
                 TypeCode typeCode = value is IConvertible convertible
                     ? convertible.GetTypeCode()
                     : Type.GetTypeCode(Enum.GetUnderlyingType(value.GetType()));
@@ -2611,6 +2617,11 @@ internal static Action<IDbCommand, object> CreateParamInfoGenerator(Identity ide
                             // simplicity, box as Nullable<SomeEnum> and call SanitizeParameterValue
                             callSanitize = checkForNull = true;
                         }
+                        else if (Settings.PersistEnumsByName)
+                        {
+                            // When PersistEnumsByName is true, SanitizeParameterValue calls ToString on an enum value.
+                            callSanitize = checkForNull = true;
+                        }
                         else
                         {
                             checkForNull = false;

docs/index.md

@@ -24,6 +24,8 @@ Note: to get the latest pre-release build, add ` -Pre` to the end of the command
 
 (note: new PRs will not be merged until they add release note wording here)
 
+- Add `Settings.PersistEnumsByName`, to support persisting an enum by its name (`Enum.ToString()`) instead of by its underlying value. (#1762 via bfriesen)
+
 ### 2.0.123
 
 - Parameters can now be re-used on subsequent commands (#952 via jamescrowley)