Improve NPoco extensions

src/Umbraco.Core/Persistence/SqlSyntaxExtensions.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Linq.Expressions;
+using System.Reflection;
+using NPoco;
+using Umbraco.Core.Persistence.SqlSyntax;
+
+namespace Umbraco.Core.Persistence
+{
+    /// <summary>
+    /// Provides extension methods to <see cref="ISqlSyntaxProvider"/>.
+    /// </summary>
+    public static class SqlSyntaxExtensions
+    {
+        private static string GetTableName(this Type type)
+        {
+            // todo: returning string.Empty for now
+            // BUT the code bits that calls this method cannot deal with string.Empty so we
+            // should either throw, or fix these code bits...
+            var attr = type.FirstAttribute<TableNameAttribute>();
+            return string.IsNullOrWhiteSpace(attr?.Value) ? string.Empty : attr.Value;
+        }
+
+        private static string GetColumnName(this PropertyInfo column)
+        {
+            var attr = column.FirstAttribute<ColumnAttribute>();
+            return string.IsNullOrWhiteSpace(attr?.Name) ? column.Name : attr.Name;
+        }
+
+        /// <summary>
+        /// Gets a quoted table and field name.
+        /// </summary>
+        /// <typeparam name="TDto">The type of the DTO.</typeparam>
+        /// <param name="sqlSyntax">An <see cref="ISqlSyntaxProvider"/>.</param>
+        /// <param name="fieldSelector">An expression specifying the field.</param>
+        /// <param name="tableAlias">An optional table alias.</param>
+        /// <returns></returns>
+        public static string GetFieldName<TDto>(this ISqlSyntaxProvider sqlSyntax, Expression<Func<TDto, object>> fieldSelector, string tableAlias = null)
+        {
+            var field = ExpressionHelper.FindProperty(fieldSelector).Item1 as PropertyInfo;
+            var fieldName = field.GetColumnName();
+
+            var type = typeof(TDto);
+            var tableName = tableAlias ?? type.GetTableName();
+
+            return sqlSyntax.GetQuotedTableName(tableName) + "." + sqlSyntax.GetQuotedColumnName(fieldName);
+        }
+    }
+}