diff --git a/src/NPoco/ColumnInfo.cs b/src/NPoco/ColumnInfo.cs
index c6b4818a..faab6334 100644
--- a/src/NPoco/ColumnInfo.cs
+++ b/src/NPoco/ColumnInfo.cs
@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
-using System.Text;
 
 namespace NPoco
 {
@@ -26,10 +25,11 @@ public class ColumnInfo
         public string ReferenceMemberName { get; set; }
         public MemberInfo MemberInfo { get; internal set; }
         public bool ExactColumnNameMatch { get; set; }
+        public IReadOnlyDictionary<string, object> Metadata { get; set; }
 
         public static ColumnInfo FromMemberInfo(MemberInfo mi)
         {
-            var ci = new ColumnInfo{MemberInfo = mi};
+            var ci = new ColumnInfo { MemberInfo = mi };
             var attrs = ReflectionUtils.GetCustomAttributes(mi).ToArray();
             var colAttrs = attrs.OfType<ColumnAttribute>().ToArray();
             var columnTypeAttrs = attrs.OfType<ColumnTypeAttribute>().ToArray();
diff --git a/src/NPoco/DefaultMapper.cs b/src/NPoco/DefaultMapper.cs
index 78a8485c..df7d14c9 100644
--- a/src/NPoco/DefaultMapper.cs
+++ b/src/NPoco/DefaultMapper.cs
@@ -1,5 +1,5 @@
 using System;
-using System.Data;
+using System.Collections.Generic;
 using System.Data.Common;
 using System.Reflection;
 
@@ -7,7 +7,7 @@ namespace NPoco
 {
     public abstract class DefaultMapper : IMapper
     {
-        public virtual Func<object, object> GetFromDbConverter(MemberInfo destMemberInfo, Type sourceType)
+        public virtual Func<object, object> GetFromDbConverter(MemberInfo destMemberInfo, Type sourceType, IReadOnlyDictionary<string, object> metadata = null)
         {
             var type = destMemberInfo.GetMemberInfoType();
             return destMemberInfo != null ? GetFromDbConverter(type, sourceType) : null;
@@ -18,7 +18,7 @@ public virtual Func<object, object> GetFromDbConverter(Type destType, Type sourc
             return null;
         }
 
-        public virtual Func<object, object> GetToDbConverter(Type destType, MemberInfo sourceMemberInfo)
+        public virtual Func<object, object> GetToDbConverter(Type destType, MemberInfo sourceMemberInfo, IReadOnlyDictionary<string, object> metadata = null)
         {
             return null;
         }
diff --git a/src/NPoco/FluentMappings/ColumnConfigurationBuilder.cs b/src/NPoco/FluentMappings/ColumnConfigurationBuilder.cs
index efc5a60e..3c906da7 100644
--- a/src/NPoco/FluentMappings/ColumnConfigurationBuilder.cs
+++ b/src/NPoco/FluentMappings/ColumnConfigurationBuilder.cs
@@ -1,8 +1,7 @@
 using System;
 using System.Collections.Generic;
-using System.Linq.Expressions;
 using System.Linq;
-using System.Reflection;
+using System.Linq.Expressions;
 
 namespace NPoco.FluentMappings
 {
@@ -118,6 +117,7 @@ public interface IColumnBuilder<TModel>
         IColumnBuilder<TModel> ValueObject();
         IColumnBuilder<TModel> ValueObject(Expression<Func<TModel, object>> member);
         IColumnBuilder<TModel> ForceToUtc(bool enabled);
+        IColumnBuilder<TModel> WithMetadata(string key, object value);
     }
 
     public class ColumnBuilder<TModel> : IColumnBuilder<TModel>
@@ -156,7 +156,7 @@ public IColumnBuilder<TModel> WithDbType(Type type)
 
         public IColumnBuilder<TModel> WithDbType<T>()
         {
-            return WithDbType(typeof (T));
+            return WithDbType(typeof(T));
         }
 
         public IColumnBuilder<TModel> Version()
@@ -253,5 +253,12 @@ public IColumnBuilder<TModel> ForceToUtc(bool enabled)
             _columnDefinition.ForceUtc = enabled;
             return this;
         }
+
+        public IColumnBuilder<TModel> WithMetadata(string key, object value)
+        {
+            _columnDefinition.Metadata ??= new Dictionary<string, object>(1);
+            _columnDefinition.Metadata.Add(key, value);
+            return this;
+        }
     }
 }
\ No newline at end of file
diff --git a/src/NPoco/FluentMappings/ColumnDefinition.cs b/src/NPoco/FluentMappings/ColumnDefinition.cs
index 3a9b064e..a2a90ec5 100644
--- a/src/NPoco/FluentMappings/ColumnDefinition.cs
+++ b/src/NPoco/FluentMappings/ColumnDefinition.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Reflection;
 
 namespace NPoco.FluentMappings
@@ -26,5 +27,6 @@ public class ColumnDefinition
         public bool? ValueObjectColumn { get; set; }
         public string ValueObjectColumnName { get; set; }
         public bool? ExactColumnNameMatch { get; set; }
+        public Dictionary<string, object> Metadata { get; set; }
     }
 }
\ No newline at end of file
diff --git a/src/NPoco/FluentMappings/FluentMappingsPocoDataBuilder.cs b/src/NPoco/FluentMappings/FluentMappingsPocoDataBuilder.cs
index cf4b7bc4..f28b6fe3 100644
--- a/src/NPoco/FluentMappings/FluentMappingsPocoDataBuilder.cs
+++ b/src/NPoco/FluentMappings/FluentMappingsPocoDataBuilder.cs
@@ -9,7 +9,7 @@ public class FluentMappingsPocoDataBuilder : PocoDataBuilder
     {
         private readonly Mappings _mappings;
 
-        public FluentMappingsPocoDataBuilder(Type type, Mappings mappings, MapperCollection mapper) : 
+        public FluentMappingsPocoDataBuilder(Type type, Mappings mappings, MapperCollection mapper) :
             base(type, mapper)
         {
             _mappings = mappings;
@@ -42,7 +42,7 @@ protected override TableInfoPlan GetTableInfo(Type type, ColumnInfo[] columnInfo
                     primaryKey = string.Join(",", originalPk);
                 }
             }
-            
+
             a = typeConfig.SequenceName ?? "";
             var sequenceName = a.Length == 0 ? null : a;
 
@@ -50,10 +50,10 @@ protected override TableInfoPlan GetTableInfo(Type type, ColumnInfo[] columnInfo
 
             // Set autoincrement false if primary key has multiple columns
             autoIncrement = autoIncrement ? !primaryKey.Contains(',') : autoIncrement;
-            
+
             // Set auto alias
             var autoAlias = CreateAlias(type.Name, type);
-            
+
             return () => new TableInfo
             {
                 TableName = tableName,
@@ -67,10 +67,10 @@ protected override TableInfoPlan GetTableInfo(Type type, ColumnInfo[] columnInfo
 
         protected override bool ShouldIncludePrivateColumn(MemberInfo mi, Type type)
         {
-            if (_mappings.Config.ContainsKey(type) 
+            if (_mappings.Config.ContainsKey(type)
                 && _mappings.Config[type].ColumnConfiguration.ContainsKey(mi.Name))
                 return true;
-            
+
             return base.ShouldIncludePrivateColumn(mi, type);
         }
 
@@ -80,7 +80,7 @@ protected override ColumnInfo GetColumnInfo(MemberInfo mi, Type type)
                 return base.GetColumnInfo(mi, type);
 
             var typeConfig = _mappings.Config[type];
-            var columnInfo = new ColumnInfo() {MemberInfo = mi};
+            var columnInfo = new ColumnInfo() { MemberInfo = mi };
             var key = mi.Name;
 
             bool explicitColumns = typeConfig.ExplicitColumns ?? false;
@@ -144,8 +144,10 @@ protected override ColumnInfo GetColumnInfo(MemberInfo mi, Type type)
                 }
 
                 columnInfo.ColumnType = colattr.DbColumnType;
+
+                columnInfo.Metadata = colattr.Metadata;
             }
-            
+
             return columnInfo;
         }
     }
diff --git a/src/NPoco/IMapper.cs b/src/NPoco/IMapper.cs
index 1973037c..d6f4d3eb 100644
--- a/src/NPoco/IMapper.cs
+++ b/src/NPoco/IMapper.cs
@@ -1,5 +1,5 @@
 using System;
-using System.Data;
+using System.Collections.Generic;
 using System.Data.Common;
 using System.Reflection;
 
@@ -7,9 +7,9 @@ namespace NPoco
 {
     public interface IMapper
     {
-        Func<object, object> GetFromDbConverter(MemberInfo memberInfo, Type sourceType);
+        Func<object, object> GetFromDbConverter(MemberInfo memberInfo, Type sourceType, IReadOnlyDictionary<string, object> metadata = null);
         Func<object, object> GetFromDbConverter(Type destType, Type sourceType);
         Func<object, object> GetParameterConverter(DbCommand dbCommand, Type sourceType);
-        Func<object, object> GetToDbConverter(Type destType, MemberInfo sourceMemberInfo);
+        Func<object, object> GetToDbConverter(Type destType, MemberInfo sourceMemberInfo, IReadOnlyDictionary<string, object> metadata = null);
     }
 }
\ No newline at end of file
diff --git a/src/NPoco/MapperCollection.cs b/src/NPoco/MapperCollection.cs
index 511b232e..e2e23fa5 100644
--- a/src/NPoco/MapperCollection.cs
+++ b/src/NPoco/MapperCollection.cs
@@ -1,7 +1,7 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Data.Common;
+using System.Linq;
 using System.Reflection;
 
 namespace NPoco
@@ -26,7 +26,7 @@ public void RegisterFactory<T>(Func<DbDataReader, T> factory)
 
         public ObjectFactoryDelegate GetFactory(Type type)
         {
-            return Factories.ContainsKey(type) ? Factories[type] : null;
+            return Factories.TryGetValue(type, out var factory) ? factory : null;
         }
 
         public bool HasFactory(Type type)
@@ -66,16 +66,16 @@ internal Func<object, object> FindFromDbConverter(Type destType, Type srcType)
             return FromDbConverterCache.Get(key, () => Find(x => x.GetFromDbConverter(destType, srcType)));
         }
 
-        internal Func<object, object> FindFromDbConverter(MemberInfo destInfo, Type srcType)
+        internal Func<object, object> FindFromDbConverter(MemberInfo destInfo, Type srcType, IReadOnlyDictionary<string, object> metadata = null)
         {
             var key = new { DestInfo = destInfo, SrcType = srcType };
-            return FromDbConverterCache.Get(key, () => Find(x => x.GetFromDbConverter(destInfo, srcType)));
+            return FromDbConverterCache.Get(key, () => Find(x => x.GetFromDbConverter(destInfo, srcType, metadata)));
         }
 
-        internal Func<object, object> FindToDbConverter(Type destType, MemberInfo srcInfo)
+        internal Func<object, object> FindToDbConverter(Type destType, MemberInfo srcInfo, IReadOnlyDictionary<string, object> metadata = null)
         {
             var key = new { DestType = destType, SrcInfo = srcInfo };
-            return ToDbConverterCache.Get(key, () => Find(x => x.GetToDbConverter(destType, srcInfo)));
+            return ToDbConverterCache.Get(key, () => Find(x => x.GetToDbConverter(destType, srcInfo, metadata)));
         }
     }
 }
\ No newline at end of file
diff --git a/src/NPoco/MappingHelper.cs b/src/NPoco/MappingHelper.cs
index 3fa2a0d6..7e8396ff 100644
--- a/src/NPoco/MappingHelper.cs
+++ b/src/NPoco/MappingHelper.cs
@@ -1,6 +1,4 @@
 using System;
-using System.Collections.Generic;
-using System.Data;
 using System.Linq;
 using System.Reflection;
 
@@ -18,21 +16,24 @@ public static Func<object, object> GetConverter(MapperCollection mapper, PocoCol
             // Get converter from the mapper
             if (mapper != null)
             {
-                converter = pc != null && pc.MemberInfoData != null ? mapper.FindFromDbConverter(pc.MemberInfoData.MemberInfo, srcType) : mapper.FindFromDbConverter(dstType, srcType);
+                converter = pc != null && pc.MemberInfoData != null
+                    ? mapper.FindFromDbConverter(pc.MemberInfoData.MemberInfo, srcType, pc.Metadata)
+                    : mapper.FindFromDbConverter(dstType, srcType);
+
                 if (converter != null)
                     return converter;
             }
 
             if (pc != null && pc.SerializedColumn && mapper?.ColumnSerializer != null)
             {
-                converter = src => mapper.ColumnSerializer.Deserialize((string) src, dstType);
+                converter = src => mapper.ColumnSerializer.Deserialize((string)src, dstType);
                 return converter;
             }
 
             // Standard DateTime->Utc mapper
             if (pc != null && pc.ForceToUtc && srcType == typeof(DateTime) && (dstType == typeof(DateTime) || dstType == typeof(DateTime?)))
             {
-                converter = src => new DateTime(((DateTime) src).Ticks, DateTimeKind.Utc);
+                converter = src => new DateTime(((DateTime)src).Ticks, DateTimeKind.Utc);
                 return converter;
             }
 
@@ -54,7 +55,7 @@ public static Func<object, object> GetConverter(MapperCollection mapper, PocoCol
             }
             else if (srcType == typeof(string) && (dstType == typeof(Guid) || dstType == typeof(Guid?)))
             {
-                converter = src => Guid.Parse((string) src);
+                converter = src => Guid.Parse((string)src);
             }
             else if ((!pc?.ValueObjectColumn ?? true) && !dstType.IsAssignableFrom(srcType))
             {
diff --git a/src/NPoco/PocoColumn.cs b/src/NPoco/PocoColumn.cs
index 92985585..7c8ea6c2 100644
--- a/src/NPoco/PocoColumn.cs
+++ b/src/NPoco/PocoColumn.cs
@@ -54,6 +54,7 @@ public Type ColumnType
         public bool ValueObjectColumn { get; set; }
         public string ValueObjectColumnName { get; set; }
         public bool ExactColumnNameMatch { get; set; }
+        public IReadOnlyDictionary<string, object> Metadata { get; set; }
 
         internal void SetMemberAccessors(List<MemberAccessor> memberAccessors)
         {
@@ -82,8 +83,8 @@ public virtual void SetValue(object target, object val)
 
         public virtual object GetValue(object target)
         {
-            return valueObjectGetter != null 
-                ? valueObjectGetter(GetRecursiveValue(target) ?? fastCreate.Create(null)) 
+            return valueObjectGetter != null
+                ? valueObjectGetter(GetRecursiveValue(target) ?? fastCreate.Create(null))
                 : GetRecursiveValue(target);
         }
 
diff --git a/src/NPoco/PocoDataBuilder.cs b/src/NPoco/PocoDataBuilder.cs
index f59e8f7e..c1899650 100644
--- a/src/NPoco/PocoDataBuilder.cs
+++ b/src/NPoco/PocoDataBuilder.cs
@@ -1,10 +1,7 @@
 using System;
-using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
-using NPoco.FluentMappings;
-using NPoco.RowMappers;
 
 namespace NPoco
 {
@@ -65,7 +62,7 @@ public ColumnInfo[] GetColumnInfos(Type type)
 
         public static bool IsDictionaryType(Type type)
         {
-            return new[] {typeof(object), typeof(IDictionary<string, object>), typeof(Dictionary<string, object>)}.Contains(type)
+            return new[] { typeof(object), typeof(IDictionary<string, object>), typeof(Dictionary<string, object>) }.Contains(type)
                 || (type.GetTypeInfo().IsGenericType && type.GetGenericTypeDefinition() == typeof(Dictionary<,>) && type.GetGenericArguments().First() == typeof(string));
         }
 
@@ -111,14 +108,14 @@ private static IEnumerable<PocoColumn> GetPocoColumns(IEnumerable<PocoMember> me
                         yield return member.PocoColumn;
                         break;
                     case ReferenceType.None:
-                    {
-                        yield return member.PocoColumn;
-                        foreach (var pocoMemberChild in GetPocoColumns(member.PocoMemberChildren))
                         {
-                            yield return pocoMemberChild;
+                            yield return member.PocoColumn;
+                            foreach (var pocoMemberChild in GetPocoColumns(member.PocoMemberChildren))
+                            {
+                                yield return pocoMemberChild;
+                            }
+                            break;
                         }
-                        break;
-                    }
                 }
             }
         }
@@ -136,8 +133,8 @@ public IEnumerable<PocoMemberPlan> GetPocoMembers(ColumnInfo[] columnInfos, List
                 if (columnInfo.ReferenceType == ReferenceType.Many)
                 {
                     var genericArguments = memberInfoType.GetGenericArguments();
-                    memberInfoType = genericArguments.Any() 
-                        ? genericArguments.First() 
+                    memberInfoType = genericArguments.Any()
+                        ? genericArguments.First()
                         : memberInfoType.GetTypeWithGenericTypeDefinitionOf(typeof(IList<>)).GetGenericArguments().First();
                 }
 
@@ -175,7 +172,7 @@ public IEnumerable<PocoMemberPlan> GetPocoMembers(ColumnInfo[] columnInfos, List
                 var fastCreate = GetFastCreate(memberType, Mapper, isList, isDynamic);
                 var columnName = GetColumnName(capturedPrefix, capturedColumnInfo.ColumnName ?? capturedMemberInfo.Name);
                 var memberInfoData = new MemberInfoData(capturedMemberInfo);
-                
+
                 yield return tableInfo =>
                 {
                     var pc = new PocoColumn
@@ -196,6 +193,7 @@ public IEnumerable<PocoMemberPlan> GetPocoMembers(ColumnInfo[] columnInfos, List
                         VersionColumnType = capturedColumnInfo.VersionColumnType,
                         SerializedColumn = capturedColumnInfo.SerializedColumn,
                         ValueObjectColumn = capturedColumnInfo.ValueObjectColumn,
+                        Metadata = capturedColumnInfo.Metadata
                     };
 
                     if (pc.ValueObjectColumn)
diff --git a/test/NPoco.Tests/Common/FirebirdDefaultMapper.cs b/test/NPoco.Tests/Common/FirebirdDefaultMapper.cs
index a851f4b0..f761272f 100644
--- a/test/NPoco.Tests/Common/FirebirdDefaultMapper.cs
+++ b/test/NPoco.Tests/Common/FirebirdDefaultMapper.cs
@@ -1,20 +1,20 @@
 using System;
+using System.Collections.Generic;
 using System.Reflection;
-using NPoco;
 
 namespace NPoco.Tests.Common
 {
-    internal class FirebirdDefaultMapper: DefaultMapper
+    internal class FirebirdDefaultMapper : DefaultMapper
     {
         private bool isNullable(Type type)
         {
-            return (type.GetTypeInfo().IsGenericType && type.GetGenericTypeDefinition() == typeof (Nullable<>));
+            return (type.GetTypeInfo().IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>));
         }
 
         public override Func<object, object> GetFromDbConverter(Type DestType, Type SourceType)
         {
             // Db:String -> Guid
-            if ((DestType == typeof (Guid)) && (SourceType == typeof (string)))
+            if ((DestType == typeof(Guid)) && (SourceType == typeof(string)))
             {
                 return src => Guid.Parse((string)src);
             }
@@ -23,9 +23,9 @@ public override Func<object, object> GetFromDbConverter(Type DestType, Type Sour
             if (isNullable(DestType))
             {
                 var underlyingType = Nullable.GetUnderlyingType(DestType);
-                if (underlyingType == typeof (Guid) )
+                if (underlyingType == typeof(Guid))
                 {
-                    return src => (src == null ? (Guid?) null : Guid.Parse((string) src));
+                    return src => (src == null ? (Guid?)null : Guid.Parse((string)src));
                 }
             }
 
@@ -50,7 +50,7 @@ public override Func<object, object> GetFromDbConverter(Type DestType, Type Sour
             return base.GetFromDbConverter(DestType, SourceType);
         }
 
-        public override Func<object, object> GetToDbConverter(Type destType, MemberInfo sourceMemberInfo)
+        public override Func<object, object> GetToDbConverter(Type destType, MemberInfo sourceMemberInfo, IReadOnlyDictionary<string, object> metadata = null)
         {
             if ((sourceMemberInfo.GetMemberInfoType() == typeof(StringObject)) && (destType == typeof(string)))
             {
diff --git a/test/NPoco.Tests/Common/User.cs b/test/NPoco.Tests/Common/User.cs
index c1d2b2c7..04fde5c8 100644
--- a/test/NPoco.Tests/Common/User.cs
+++ b/test/NPoco.Tests/Common/User.cs
@@ -1,5 +1,4 @@
 using System;
-using NPoco;
 
 namespace NPoco.Tests.Common
 {
@@ -43,7 +42,7 @@ public User()
     public class StringObject
     {
         public string MyValue { get; set; }
-        
+
         public override string ToString()
         {
             return MyValue;
diff --git a/test/NPoco.Tests/DecoratedTests/CRUDTests/UpdateTests.cs b/test/NPoco.Tests/DecoratedTests/CRUDTests/UpdateTests.cs
index 1ddae3fa..e0add32e 100644
--- a/test/NPoco.Tests/DecoratedTests/CRUDTests/UpdateTests.cs
+++ b/test/NPoco.Tests/DecoratedTests/CRUDTests/UpdateTests.cs
@@ -1,11 +1,11 @@
-using System;
+using Newtonsoft.Json;
+using NPoco.Tests.Common;
+using NUnit.Framework;
+using System;
 using System.Collections.Generic;
 using System.Data;
 using System.Linq;
 using System.Reflection;
-using Newtonsoft.Json;
-using NPoco.Tests.Common;
-using NUnit.Framework;
 
 namespace NPoco.Tests.DecoratedTests.CRUDTests
 {
@@ -19,7 +19,7 @@ public void UpdatePrimaryKeyObject()
             Assert.IsNotNull(poco);
 
             poco.Age = InMemoryUsers[1].Age + 100;
-            poco.Savings = (Decimal) 1234.23;
+            poco.Savings = (Decimal)1234.23;
             Database.Update(poco);
 
             var verify = Database.SingleOrDefaultById<UserDecorated>(InMemoryUsers[1].UserId);
@@ -38,7 +38,7 @@ public void UpdatePrimaryKeyObjectOverridingPrimaryKey()
             Assert.IsNotNull(poco);
 
             poco.Age = InMemoryUsers[1].Age + 100;
-            poco.Savings = (Decimal) 1234.23;
+            poco.Savings = (Decimal)1234.23;
             Database.Update(poco, InMemoryUsers[2].UserId);
 
             var verify = Database.SingleOrDefaultById<UserDecorated>(InMemoryUsers[2].UserId);
@@ -84,7 +84,7 @@ public void UpdateWithFields()
             Assert.IsNotNull(poco);
 
             poco.Age = poco.Age + 100;
-            poco.Savings = (Decimal) 1234.23;
+            poco.Savings = (Decimal)1234.23;
             Database.Update(poco, x => x.Age);
 
             var verify = Database.SingleOrDefaultById<UserDecorated>(1);
@@ -232,7 +232,7 @@ public class UserModel
 
         public class MyMapper : DefaultMapper
         {
-            public override Func<object, object> GetToDbConverter(Type destType, MemberInfo sourceMemberInfo)
+            public override Func<object, object> GetToDbConverter(Type destType, MemberInfo sourceMemberInfo, IReadOnlyDictionary<string, object> metadata = null)
             {
                 if ((destType == typeof(string)) && (sourceMemberInfo.GetMemberInfoType() == typeof(IDictionary<string, object>)))
                 {
diff --git a/test/NPoco.Tests/FluentMappings/MapTests.cs b/test/NPoco.Tests/FluentMappings/MapTests.cs
index 8d4a02d0..2047f483 100644
--- a/test/NPoco.Tests/FluentMappings/MapTests.cs
+++ b/test/NPoco.Tests/FluentMappings/MapTests.cs
@@ -1,6 +1,7 @@
 using NPoco.FluentMappings;
 using NPoco.Tests.Common;
 using NUnit.Framework;
+using System.Linq;
 
 namespace NPoco.Tests.FluentMappings
 {
@@ -83,10 +84,10 @@ public void InheritColumns()
         {
             var typeDefinition = new TypeDefinition(typeof(User));
             var map = new TestMap(typeDefinition);
-            
+
             var typeDefinition1 = new TypeDefinition(typeof(Supervisor));
             var map1 = new SupervisorMap(typeDefinition1);
-            
+
             Assert.AreEqual(4, typeDefinition1.ColumnConfiguration.Count);
             Assert.IsTrue(typeDefinition1.ColumnConfiguration["Age"].IgnoreColumn ?? false);
             Assert.IsTrue(typeDefinition1.ColumnConfiguration["IsSupervisor"].ResultColumn ?? false);
@@ -103,6 +104,15 @@ public void InheritColumnsButRemoveColumnsNotFound()
 
             Assert.AreEqual(1, typeDefinition1.ColumnConfiguration.Count);
         }
+
+        [Test]
+        public void MetadataDefinition()
+        {
+            var typeDefinition = new TypeDefinition(typeof(User));
+            var map = new TestMetadataMap(typeDefinition);
+
+            Assert.AreEqual("TestKey", typeDefinition.ColumnConfiguration["Name"].Metadata.Keys.First());
+        }
     }
 
     public class TestMap : Map<UserWithNullableId>
@@ -113,4 +123,12 @@ public TestMap(TypeDefinition typeDefinition) : base(typeDefinition)
             Columns(x => x.Column(y => y.Days).Result());
         }
     }
+
+    public class TestMetadataMap : Map<User>
+    {
+        public TestMetadataMap(TypeDefinition typeDefinition) : base(typeDefinition)
+        {
+            Columns(x => x.Column(y => y.Name).WithMetadata("TestKey", new object()));
+        }
+    }
 }
diff --git a/test/NPoco.Tests/NewMapper/NewMapperTests.cs b/test/NPoco.Tests/NewMapper/NewMapperTests.cs
index 666beb22..84d58806 100644
--- a/test/NPoco.Tests/NewMapper/NewMapperTests.cs
+++ b/test/NPoco.Tests/NewMapper/NewMapperTests.cs
@@ -1,13 +1,13 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Reflection;
-using NPoco.Expressions;
+using NPoco.Expressions;
 using NPoco.fastJSON;
 using NPoco.Linq;
 using NPoco.Tests.Common;
 using NPoco.Tests.NewMapper.Models;
 using NUnit.Framework;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
 
 namespace NPoco.Tests.NewMapper
 {
@@ -654,7 +654,7 @@ public void Test28A()
 
         public class TestMapper : DefaultMapper
         {
-            public override Func<object, object> GetFromDbConverter(MemberInfo destType, Type sourceType)
+            public override Func<object, object> GetFromDbConverter(MemberInfo destType, Type sourceType, IReadOnlyDictionary<string, object> metadata = null)
             {
                 if (destType.GetMemberInfoType() == typeof(Test28AClass.Nest4) && sourceType == typeof(string))
                 {
@@ -726,7 +726,7 @@ public void Test32()
         public void Test33()
         {
             var users = Database.Query<UserDecorated>()
-                .WhereSql(x=> new Sql($"{x.DatabaseType.EscapeTableName(x.PocoData.TableInfo.AutoAlias)}.UserId in (@list)", new {list = new[] {2}}))
+                .WhereSql(x => new Sql($"{x.DatabaseType.EscapeTableName(x.PocoData.TableInfo.AutoAlias)}.UserId in (@list)", new { list = new[] { 2 } }))
                 .Where(x => x.UserId.In(new[] { 1, 2 }))
                 .OrderBy(x => x.UserId)
                 .ToList();
@@ -751,8 +751,8 @@ public void Test34()
         [Test]
         public void Test35()
         {
-            var data = new Result35.ResultData() {Name = "Bob", Age = 66};
-            var result = Database.Single<Result35>("select @0 as Data", JSON.ToJSON(new[] {data}));
+            var data = new Result35.ResultData() { Name = "Bob", Age = 66 };
+            var result = Database.Single<Result35>("select @0 as Data", JSON.ToJSON(new[] { data }));
             Assert.AreEqual(data.Name, result.Data[0].Name);
             Assert.AreEqual(data.Age, result.Data[0].Age);
         }