Add GenericTableExpressions example using a modified ModelDef at runtime

Author: mythz

tests/ServiceStack.OrmLite.Tests/Expression/GenericTableExpressions.cs

@@ -0,0 +1,93 @@
+using System;
+using System.Collections.Generic;
+using System.Data;
+using System.Linq.Expressions;
+using NUnit.Framework;
+using ServiceStack.DataAnnotations;
+using ServiceStack.Logging;
+
+namespace ServiceStack.OrmLite.Tests.Expression
+{
+    public class GenericEntity
+    {
+        public int Id { get; set; }
+
+        [Alias("COL_A")]
+        public string ColumnA { get; set; }
+    }
+
+    [TestFixture]
+    public class GenericTableExpressions : OrmLiteTestBase
+    {
+        [Test]
+        public void Can_change_table_at_runtime()
+        {
+            LogManager.LogFactory = new ConsoleLogFactory();
+
+            const string tableName = "Entity1";
+            using (var db = OpenDbConnection())
+            {
+                db.DropAndCreateTable<GenericEntity>(tableName);
+
+                db.Insert(tableName, new GenericEntity { Id = 1, ColumnA = "A" });
+
+                var rows = db.Select<GenericEntity>(tableName, q =>
+                    q.Where(x => x.ColumnA == "A"));
+
+                Assert.That(rows.Count, Is.EqualTo(1));
+
+                db.Update(tableName, new GenericEntity { ColumnA = "B" },
+                    where: q => q.ColumnA == "A");
+
+                rows = db.Select<GenericEntity>(tableName, q => 
+                    q.Where(x => x.ColumnA == "B"));
+
+                Assert.That(rows.Count, Is.EqualTo(1));
+            }
+        }
+    }
+
+    public static class GenericTableExtensions
+    {
+        static object ExecWithAlias<T>(string table, Func<object> fn)
+        {
+            var modelDef = typeof(T).GetModelMetadata();
+            lock (modelDef)
+            {
+                var hold = modelDef.Alias;
+                try
+                {
+                    modelDef.Alias = table;
+                    return fn();
+                }
+                finally
+                {
+                    modelDef.Alias = hold;
+                }
+            }
+        }
+
+        public static void DropAndCreateTable<T>(this IDbConnection db, string table)
+        {
+            ExecWithAlias<T>(table, () => { 
+                db.DropAndCreateTable<T>();
+                return null;
+            });
+        }
+
+        public static long Insert<T>(this IDbConnection db, string table, T obj, bool selectIdentity = false)
+        {
+            return (long)ExecWithAlias<T>(table, () => db.Insert(obj, selectIdentity));
+        }
+
+        public static List<T> Select<T>(this IDbConnection db, string table, Func<SqlExpression<T>, SqlExpression<T>> expression)
+        {
+            return (List<T>)ExecWithAlias<T>(table, () => db.Select(expression));
+        }
+
+        public static int Update<T>(this IDbConnection db, string table, T item, Expression<Func<T, bool>> where)
+        {
+            return (int)ExecWithAlias<T>(table, () => db.Update(item, where));
+        }
+    }
+}

tests/ServiceStack.OrmLite.Tests/ServiceStack.OrmLite.Tests.csproj

@@ -121,6 +121,7 @@
     <Compile Include="DateTimeOffsetTests.cs" />
     <Compile Include="Expression\ExpressionUsingCustomSerializedEnumTests.cs" />
     <Compile Include="Expression\FromExpressionTests.cs" />
+    <Compile Include="Expression\GenericTableExpressions.cs" />
     <Compile Include="Expression\MethodExpressionTests.cs" />
     <Compile Include="Expression\SqlExpressionTests.cs" />
     <Compile Include="Expression\SelectExpressionTests.cs" />