Here are some fixes for the problems. Unfortunately, not complete.

Author: BruceCowan-AI

src/ServiceStack.OrmLite.Oracle/Converters/OracleByteArrayConverter.cs

@@ -5,11 +5,6 @@ namespace ServiceStack.OrmLite.Oracle.Converters
 {
     public class OracleByteArrayConverter : ByteArrayConverter
     {
-        public override object ToDbValue(Type fieldType, object value)
-        {
-            return "hextoraw('" + BitConverter.ToString((byte[])value).Replace("-", "") + "')";
-        }
-
         public override string ToQuotedString(Type fieldType, object value)
         {
             return "hextoraw('" + BitConverter.ToString((byte[])value).Replace("-", "") + "')";

src/ServiceStack.OrmLite.Oracle/Converters/OracleDateTimeOffsetConverter.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Data;
 using ServiceStack.OrmLite.Converters;
 
 namespace ServiceStack.OrmLite.Oracle.Converters
@@ -38,5 +39,10 @@ public override object FromDbValue(Type fieldType, object value)
         {
             return Convert.ChangeType(value, typeof(DateTimeOffset));
         }
+
+        public override void InitDbParam(IDbDataParameter p, Type fieldType)
+        {
+            p.DbType = DbType.String;
+        }
     }
 }

src/ServiceStack.OrmLite.Oracle/Converters/OracleEnumConverter.cs

@@ -12,14 +12,18 @@ public override string ToQuotedString(Type fieldType, object value)
                 value = fieldType.GetEnumName(value);
             }
 
-            var enumValue = DialectProvider.StringSerializer.SerializeToString(value);
-            // Oracle stores empty strings in varchar columns as null so match that behavior here
-            if (enumValue == null)
-                return null;
-            enumValue = DialectProvider.GetQuotedValue(enumValue.Trim('"'));
-            return enumValue == "''"
-                ? "null"
-                : enumValue;
+            if (fieldType.IsEnum)
+            {
+                var enumValue = DialectProvider.StringSerializer.SerializeToString(value);
+                // Oracle stores empty strings in varchar columns as null so match that behavior here
+                if (enumValue == null)
+                    return null;
+                enumValue = DialectProvider.GetQuotedValue(enumValue.Trim('"'));
+                return enumValue == "''"
+                    ? "null"
+                    : enumValue;
+            }
+            return base.ToQuotedString(fieldType, value);
         }
 
         public override object ToDbValue(Type fieldType, object value)

src/ServiceStack.OrmLite.Oracle/OracleOrmLiteDialectProvider.cs

@@ -87,6 +87,7 @@ public OracleOrmLiteDialectProvider(bool compactGuid, bool quoteNames, string cl
             //DefaultStringLength = 128;
 
             ParamString = ":";
+//            OrmLiteConfig.UseParameterizeSqlExpressions = true;
 
             NamingStrategy = new OracleNamingStrategy(MaxNameLength);
             ExecFilter = new OracleExecFilter();
@@ -107,6 +108,7 @@ public OracleOrmLiteDialectProvider(bool compactGuid, bool quoteNames, string cl
             RegisterConverter<TimeSpan>(new OracleTimeSpanAsIntConverter());
             RegisterConverter<string>(new OracleStringConverter());
             RegisterConverter<char[]>(new OracleCharArrayConverter());
+            RegisterConverter<byte[]>(new OracleByteArrayConverter());
 
             RegisterConverter<long>(new OracleInt64Converter());
             RegisterConverter<sbyte>(new OracleSByteConverter());

src/ServiceStack.OrmLite/OrmLiteResultsFilterExtensions.cs

@@ -103,8 +103,8 @@ public static IList ConvertToList(this IDbCommand dbCmd, Type refType, string sq
         public static IDbDataParameter PopulateWith(this IDbDataParameter to, IDbDataParameter from)
         {
             to.ParameterName = from.ParameterName;
-            to.Value = from.Value;
             to.DbType = from.DbType;
+            to.Value = from.Value;
 
             if (from.Precision != default(byte))
                 to.Precision = from.Precision;