Force nonhierachical property: sink logic

* Disable a property from being resolved hierarchically/structured even if its name contains dots (serilog-mssql#542) be addin a new new column option `ResolveHierarchicalPropertyName`.
* Implemented logic in SqlColumn class.
* Implemented reading of new column option from config.

Issue serilog-mssql#542

src/Serilog.Sinks.MSSqlServer/Configuration/Implementations/System.Configuration/ColumnCollection.cs

@@ -1,11 +1,11 @@
 // Copyright 2015 Serilog Contributors
-// 
+//
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
-// 
+//
 //     http://www.apache.org/licenses/LICENSE-2.0
-// 
+//
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -30,6 +30,12 @@ protected override object GetElementKey(ConfigurationElement element)
         {
             return ((ColumnConfig)element)?.ColumnName;
         }
+
+        // For testing
+        internal void Add(ColumnConfig config)
+        {
+            BaseAdd(config);
+        }
     }
 }
 

src/Serilog.Sinks.MSSqlServer/Configuration/Implementations/System.Configuration/ColumnConfig.cs

@@ -1,11 +1,11 @@
 // Copyright 2015 Serilog Contributors
-// 
+//
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
-// 
+//
 //     http://www.apache.org/licenses/LICENSE-2.0
-// 
+//
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -48,6 +48,13 @@ public virtual string PropertyName
             set { this[nameof(PropertyName)] = value; }
         }
 
+        [ConfigurationProperty("ResolveHierarchicalPropertyName")]
+        public virtual string ResolveHierarchicalPropertyName
+        {
+            get { return (string)this[nameof(ResolveHierarchicalPropertyName)]; }
+            set { this[nameof(ResolveHierarchicalPropertyName)] = value; }
+        }
+
         [ConfigurationProperty("DataType")]
         public string DataType
         {
@@ -85,6 +92,8 @@ internal SqlColumn AsSqlColumn()
 
             SetProperty.IfProvidedNotEmpty<string>(this, nameof(PropertyName), (val) => sqlColumn.PropertyName = val);
 
+            SetProperty.IfProvided<bool>(this, nameof(ResolveHierarchicalPropertyName), (val) => sqlColumn.ResolveHierarchicalPropertyName = val);
+
             SetProperty.IfProvidedNotEmpty<string>(this, nameof(DataType), (val) => sqlColumn.SetDataTypeFromConfigString(val));
 
             SetProperty.IfProvided<int>(this, nameof(DataLength), (val) => sqlColumn.DataLength = val);

src/Serilog.Sinks.MSSqlServer/Sinks/MSSqlServer/SqlColumn.cs

@@ -13,6 +13,7 @@ public class SqlColumn
         private SqlDbType _dataType = SqlDbType.VarChar; // backwards-compatibility default
         private string _columnName = string.Empty;
         private string _propertyName;
+        private bool _resolveHierarchicalPropertyName = true;
         private readonly List<string> _propertyNameHierarchy = new List<string>();
 
         /// <summary>
@@ -109,7 +110,20 @@ public string PropertyName
             set
             {
                 _propertyName = value;
-                ParseHierarchicalPropertyName(value);
+                ParseHierarchicalPropertyName();
+            }
+        }
+
+        /// <summary>
+        /// Controls whether hierarchical expressions in `PropertyName` are evaluated. The default is `true`.
+        /// </summary>
+        public bool ResolveHierarchicalPropertyName
+        {
+            get => _resolveHierarchicalPropertyName;
+            set
+            {
+                _resolveHierarchicalPropertyName = value;
+                ParseHierarchicalPropertyName();
             }
         }
 
@@ -130,8 +144,6 @@ internal bool HasHierarchicalPropertyName
         // and allows casting back to the Standard Column without a lot of switch gymnastics.
         internal StandardColumn? StandardColumnIdentifier { get; set; }
 
-        internal Type StandardColumnType { get; set; }
-
         /// <summary>
         /// Converts a SQL sink SqlColumn object to a System.Data.DataColumn object. The original
         /// SqlColumn object is stored in the DataColumn's ExtendedProperties collection.
@@ -170,9 +182,17 @@ internal void SetDataTypeFromConfigString(string requestedSqlType)
             DataType = sqlType;
         }
 
-        private void ParseHierarchicalPropertyName(string propertyName)
+        private void ParseHierarchicalPropertyName()
         {
-            _propertyNameHierarchy.AddRange(propertyName.Split('.'));
+            _propertyNameHierarchy.Clear();
+            if (ResolveHierarchicalPropertyName)
+            {
+                _propertyNameHierarchy.AddRange(PropertyName.Split('.'));
+            }
+            else
+            {
+                _propertyNameHierarchy.Add(PropertyName);
+            }
         }
     }
 }