Merge pull request #22 from DataAction/column-aliases

Make sure resulting column aliases are used if available

Author: c-j-hughes

src/AdoNetCore.AseClient/AseDataReader.cs

@@ -472,7 +472,7 @@ public override string GetName(int i)
                 throw new ArgumentOutOfRangeException(nameof(i));
             }
 
-            return format.ColumnName;
+            return format.DisplayColumnName;
         }
 
         public override int GetOrdinal(string name)
@@ -495,7 +495,7 @@ public override int GetOrdinal(string name)
 
             for (var i = 0; i < formats.Length; i++)
             {
-                if (string.Equals(formats[i].ColumnName?.TrimStart('[').TrimEnd(']'), name, StringComparison.OrdinalIgnoreCase))
+                if (string.Equals(formats[i].DisplayColumnName?.TrimStart('[').TrimEnd(']'), name, StringComparison.OrdinalIgnoreCase))
                 {
                     return i;
                 }
@@ -640,7 +640,7 @@ private void EnsureSchemaTable()
                 var row = table.NewRow();
                 var aseDbType = TypeMap.GetAseDbType(column);
 
-                row[columnName] = string.IsNullOrWhiteSpace(column.ColumnLabel) ? column.ColumnName : column.ColumnLabel;
+                row[columnName] = column.DisplayColumnName;
                 row[columnOrdinal] = i;
                 row[columnSize] = column.Length ?? -1;
                 row[numericPrecision] = column.Precision ?? -1;

src/AdoNetCore.AseClient/Internal/FormatItem.cs

@@ -32,6 +32,15 @@ public string ParameterName
         public bool IsNullable { get; set; }
         public bool IsOutput { get; set; }
 
+        /// <summary>
+        /// Get the most appropriate column name to display to the driver user.
+        /// Preference is to the Label/Alias (e.g. "some_alias" from "select some_column as some_alias")
+        /// If no Label/Alias, then just use whatever value the underlying column name has.
+        /// </summary>
+        public string DisplayColumnName => string.IsNullOrWhiteSpace(ColumnLabel)
+            ? ColumnName
+            : ColumnLabel;
+
         /// <summary>
         /// Relates to TDS_BLOB
         /// </summary>
@@ -104,6 +113,7 @@ public static FormatItem ReadForRow(Stream stream, Encoding enc, TokenType srcTo
             ReadTypeInfo(format, stream, enc);
 
             Logger.Instance?.WriteLine($"  <- {format.ColumnName}: {format.DataType} (len: {format.Length}) (ut:{format.UserType}) (status:{format.RowStatus}) (loc:{format.LocaleInfo})");
+            Logger.Instance?.WriteLine($"  <- format names available: ColumnLabel [{format.ColumnLabel}], ColumnName [{format.ColumnName}], CatalogName [{format.CatalogName}], ParameterName [{format.ParameterName}], SchemaName [{format.SchemaName}], TableName [{format.TableName}]");
 
             return format;
         }
@@ -186,7 +196,7 @@ private static void ReadTypeInfo(FormatItem format, Stream stream, Encoding enc)
                         break;
                     }
                 default:
-                    throw new NotSupportedException($"Unsupported data type {format.DataType} (column: {format.ColumnName})");
+                    throw new NotSupportedException($"Unsupported data type {format.DataType} (column: {format.DisplayColumnName})");
             }
 
             format.LocaleInfo = stream.ReadByteLengthPrefixedString(enc);

test/AdoNetCore.AseClient.Tests/AdoNetCore.AseClient.Tests.csproj

@@ -33,9 +33,6 @@
     <PackageReference Include="System.Data.Common" Version="4.3.0" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp2.0'">
-    <PackageReference Include="Sybase.AdoNet4.AseClient">
-      <Version>1.0.0</Version>
-    </PackageReference>
     <PackageReference Include="System.Security.Permissions">
       <Version>4.4.1</Version>
     </PackageReference>

test/AdoNetCore.AseClient.Tests/Integration/AliasTests.cs

@@ -0,0 +1,102 @@
+using System;
+using System.Data;
+using System.Linq;
+using AdoNetCore.AseClient.Internal;
+using Dapper;
+using NUnit.Framework;
+
+namespace AdoNetCore.AseClient.Tests.Integration
+{
+    [TestFixture]
+    public class AliasTests
+    {
+        private IDbConnection GetConnection()
+        {
+            Logger.Enable();
+            return new AseConnection(ConnectionStrings.Pooled);
+        }
+
+        [SetUp]
+        public void Setup()
+        {
+            using (var connection = GetConnection())
+            {
+                connection.Execute("create table [dbo].[test_aliases] (column_with_table_name int)");
+                connection.Execute("insert into [dbo].[test_aliases] (column_with_table_name) values (1)");
+            }
+        }
+
+        [TestCase]
+        public void SelectColumnWithoutAlias_UsesColumnName_InResultSet()
+        {
+            using (var connection = GetConnection())
+            {
+                connection.Open();
+                using (var command = connection.CreateCommand())
+                {
+                    command.CommandText = "select column_with_table_name from [dbo].[test_aliases]";
+
+                    using (var reader = command.ExecuteReader(CommandBehavior.SingleRow))
+                    {
+                        Assert.AreEqual(0, reader.GetOrdinal("column_with_table_name"));
+                        Assert.Throws<ArgumentException>(() => reader.GetOrdinal("aliased_name"));
+                    }
+                }
+            }
+        }
+
+        [TestCase]
+        public void SelectColumnWithAlias_UsesAliasName_InResultSet()
+        {
+            using (var connection = GetConnection())
+            {
+                connection.Open();
+                using (var command = connection.CreateCommand())
+                {
+                    command.CommandText = "select column_with_table_name as aliased_name from [dbo].[test_aliases]";
+
+                    using (var reader = command.ExecuteReader(CommandBehavior.SingleRow))
+                    {
+                        Assert.AreEqual(0, reader.GetOrdinal("aliased_name"));
+                        Assert.Throws<ArgumentException>(() => reader.GetOrdinal("column_with_table_name"));
+                    }
+                }
+            }
+        }
+
+        private class AliasTestsDapperResult
+        {
+            public int? column_with_table_name { get; set; }
+            public int? aliased_name { get; set; }
+        }
+
+        [TestCase]
+        public void SelectColumnWithoutAlias_UsesColumnName_InDapperResult()
+        {
+            using (var connection = GetConnection())
+            {
+                var result = connection.Query<AliasTestsDapperResult>("select column_with_table_name from [dbo].[test_aliases]", commandType: CommandType.Text).FirstOrDefault();
+                Assert.IsNotNull(result?.column_with_table_name);
+            }
+        }
+
+        [TestCase]
+        public void SelectColumnWithAlias_UsesAliasName_InDapperResult()
+        {
+            using (var connection = GetConnection())
+            {
+                var result = connection.Query<AliasTestsDapperResult>("select column_with_table_name as aliased_name from [dbo].[test_aliases]", commandType: CommandType.Text).FirstOrDefault();
+                Assert.IsNotNull(result?.aliased_name);
+            }
+        }
+
+        [TearDown]
+        public void Teardown()
+        {
+            using (var connection = GetConnection())
+            {
+                connection.Execute("drop table [dbo].[test_aliases]");
+            }
+        }
+    }
+}