Issue 1097 : Enhancement: Introduce the LiteralQueryField

RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/Extensions/QueryFields/LiteralQuerFieldTest.cs

@@ -0,0 +1,31 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using RepoDb.Extensions.QueryFields;
+
+namespace RepoDb.UnitTests.Extensions.QueryFields
+{
+    [TestClass]
+    public class LiteralQuerFieldTest
+	{
+        [TestMethod]
+        public void TestLiteralQueryFieldConstructor()
+        {
+            // Prepare
+            var literalQueryField = new LiteralQueryField("[Id] BETWEEN 10 AND 100");
+
+            // Assert
+            Assert.AreEqual("fake", literalQueryField.Field.Name);
+            Assert.AreEqual("[Id] BETWEEN 10 AND 100", literalQueryField.Literal);
+        }
+
+        [TestMethod]
+        public void TestLiteralQueryFieldGetString()
+        {
+            // Prepare
+            var literalQueryField = new LiteralQueryField("[Id] BETWEEN 10 AND 100");
+
+            // Assert
+            Assert.AreEqual("[Id] BETWEEN 10 AND 100", literalQueryField.GetString(0, null));
+        }
+    }
+}
+

RepoDb.Core/RepoDb/Extensions/QueryFields/LiteralQueryField.cs

@@ -0,0 +1,56 @@
+using System;
+using System.Data;
+using RepoDb.Enumerations;
+using RepoDb.Interfaces;
+
+namespace RepoDb.Extensions.QueryFields
+{
+    /// <summary>
+    /// Query field that uses exactl what is passed.
+    /// </summary>
+    /// <example>
+    /// See sample code below that uses a BETWEEN function.
+    /// <code>
+    ///     var where = new LiteralQueryField("ColumnName BETWEEN 1 AND 10");
+    ///     var result = connection.Query&lt;Entity&gt;(where);
+    /// </code>
+    /// </example>
+	public class LiteralQueryField : QueryField
+    {
+        #region Properties
+
+        public string Literal { get; set; }
+
+        #endregion
+
+        #region Constructors
+
+        /// <summary>
+        /// Creates a new instance of <see cref="FunctionalQueryField"/> object.
+        /// </summary>
+        /// <param name="literal">The content of the where as is.</param>
+        public LiteralQueryField(string literal)
+            // Both of the parameters are actually ignored.
+            : base("fake", Operation.Equal, null, null)
+        {
+            Literal = literal;
+        }
+
+        #endregion
+
+        #region Methods
+
+        /// <summary>
+        /// Gets the string representations (column-value pairs) of the current <see cref="QueryField"/> object with the formatted-function transformations.
+        /// </summary>
+        /// <param name="index">The target index.</param>
+        /// <param name="dbSetting">The database setting currently in used.</param>
+        /// <returns>The string representations of the current <see cref="QueryField"/> object using the LOWER function.</returns>
+        public override string GetString(int index,
+            IDbSetting dbSetting) =>
+            Literal;
+
+        #endregion
+    }
+}
+