The SqlTableDifferences use a primary key object instance of a list to represents the difference of primary key (fixes #8).

Author: GillesTourreau

src/Testing.Databases.SqlServer/Comparer/SqlDatabaseComparisonResultsTextGenerator.cs

@@ -105,7 +105,7 @@ public void Visit(SqlTableDifferences differences)
 
                 this.Generate(differences.Indexes, "Indexes");
 
-                this.Generate(differences.PrimaryKeys, "Primary keys");
+                this.Generate(differences.PrimaryKey, "Primary key");
 
                 this.Generate(differences.Triggers, "Triggers");
 

src/Testing.Databases.SqlServer/Comparer/SqlObjectComparer.cs

@@ -211,17 +211,20 @@ public static IList<SqlTableDifferences> Compare(IReadOnlyList<SqlTable> source,
             var indexesDifferences = Compare(sourceTable.Indexes, table.Indexes, i => i.Name, diff => new SqlIndexDifferences(diff));
 
             // Compare the primary key
-            var primaryKeyDifferences = Compare(CreateArray(sourceTable.PrimaryKey), CreateArray(table.PrimaryKey), pk => pk.Name, diff => new SqlPrimaryKeyDifferences(diff));
+            var primaryKeyDifferences = (SqlPrimaryKeyDifferences?)Compare(sourceTable.PrimaryKey, table.PrimaryKey);
 
             // Compare the triggers
             var triggersDifferences = Compare(sourceTable.Triggers, table.Triggers, tr => tr.Name);
 
             // Compare the unique constraints
             var uniqueConstraintsDifferences = Compare(sourceTable.UniqueConstraints, table.UniqueConstraints, uc => uc.Name, diff => new SqlUniqueConstraintDifferences(diff));
 
-            if (columnsDifferences.Count + triggersDifferences.Count + checkConstraintDifferences.Count + indexesDifferences.Count + foreignKeysDifferences.Count + uniqueConstraintsDifferences.Count + primaryKeyDifferences.Count > 0)
+            if (columnsDifferences.Count + triggersDifferences.Count + checkConstraintDifferences.Count + indexesDifferences.Count + foreignKeysDifferences.Count + uniqueConstraintsDifferences.Count > 0 || primaryKeyDifferences is not null)
             {
-                return new SqlTableDifferences(sourceTable, table, SqlObjectDifferenceType.Different, [], primaryKeyDifferences, columnsDifferences, triggersDifferences, checkConstraintDifferences, indexesDifferences, foreignKeysDifferences, uniqueConstraintsDifferences);
+                return new SqlTableDifferences(sourceTable, table, SqlObjectDifferenceType.Different, [], columnsDifferences, triggersDifferences, checkConstraintDifferences, indexesDifferences, foreignKeysDifferences, uniqueConstraintsDifferences)
+                {
+                    PrimaryKey = primaryKeyDifferences,
+                };
             }
 
             return this.CreateDifferences(table);
@@ -328,17 +331,6 @@ private static IReadOnlyList<SqlObjectPropertyDifference> GetPropertyDifferences
             return objects.SingleOrDefault(o => Equals(keySelector(o), value));
         }
 
-        private static T[] CreateArray<T>(T? value)
-            where T : class
-        {
-            if (value is null)
-            {
-                return [];
-            }
-
-            return [value];
-        }
-
         private SqlObjectPropertyDifference? CompareProperty<TSqlObject>(TSqlObject target, Func<TSqlObject, object?> propertyValueForComparison, string name, Func<TSqlObject, object?>? propertyValueToDisplay = null)
             where TSqlObject : SqlObject
         {

src/Testing.Databases.SqlServer/Comparer/SqlTableDifferences.cs

@@ -18,7 +18,6 @@ internal SqlTableDifferences(
             SqlTable? target,
             SqlObjectDifferenceType type,
             IReadOnlyList<SqlObjectPropertyDifference>? properties,
-            IList<SqlPrimaryKeyDifferences> primaryKeys,
             IList<SqlColumnDifferences> columns,
             IList<SqlObjectDifferences<SqlTrigger>> triggers,
             IList<SqlObjectDifferences<SqlCheckConstraint>> checkConstraints,
@@ -27,7 +26,6 @@ internal SqlTableDifferences(
             IList<SqlUniqueConstraintDifferences> uniqueConstraints)
             : base(source, target, type, properties)
         {
-            this.PrimaryKeys = new ReadOnlyCollection<SqlPrimaryKeyDifferences>(primaryKeys);
             this.Columns = new ReadOnlyCollection<SqlColumnDifferences>(columns);
             this.Triggers = new ReadOnlyCollection<SqlObjectDifferences<SqlTrigger>>(triggers);
             this.CheckConstraints = new ReadOnlyCollection<SqlObjectDifferences<SqlCheckConstraint>>(checkConstraints);
@@ -38,7 +36,7 @@ internal SqlTableDifferences(
 
         internal SqlTableDifferences(
             SqlObjectDifferences<SqlTable> differences)
-            : this(differences.Source, differences.Target, differences.Type, differences.Properties, [], [], [], [], [], [], [])
+            : this(differences.Source, differences.Target, differences.Type, differences.Properties, [], [], [], [], [], [])
         {
         }
 
@@ -60,7 +58,7 @@ internal SqlTableDifferences(
         /// <summary>
         /// Gets the primary key differences between the two SQL tables.
         /// </summary>
-        public ReadOnlyCollection<SqlPrimaryKeyDifferences> PrimaryKeys { get; }
+        public SqlPrimaryKeyDifferences? PrimaryKey { get; internal set; }
 
         /// <summary>
         /// Gets the foreign keys differences between the two SQL tables.

tests/Testing.Databases.SqlServer.Tests.Source/Tables/TableWithDifferentPrimaryKey.sql

@@ -0,0 +1,6 @@
+CREATE TABLE [dbo].[TableWithDifferentPrimaryKey]
+(
+	[Id] INT NOT NULL,
+
+	CONSTRAINT [PK_TableWithDifferentPrimaryKey_Source] PRIMARY KEY CLUSTERED ([Id] ASC)
+)

tests/Testing.Databases.SqlServer.Tests.Source/Testing.Databases.SqlServer.Tests.Source.sqlproj

@@ -101,5 +101,6 @@
     <Build Include="Views\ViewSource.sql" />
     <Build Include="Views\ViewDifference.sql" />
     <Build Include="Tables\__EFMigrationsHistorySource.sql" />
+    <Build Include="Tables\TableWithDifferentPrimaryKey.sql" />
   </ItemGroup>
 </Project>

tests/Testing.Databases.SqlServer.Tests.Target/Tables/TableWithDifferentPrimaryKey.sql

@@ -0,0 +1,6 @@
+CREATE TABLE [dbo].[TableWithDifferentPrimaryKey]
+(
+	[Id] INT NOT NULL,
+
+	CONSTRAINT [PK_TableWithDifferentPrimaryKey_Target] PRIMARY KEY CLUSTERED ([Id] ASC)
+)

tests/Testing.Databases.SqlServer.Tests.Target/Testing.Databases.SqlServer.Tests.Target.sqlproj

@@ -115,5 +115,6 @@
     <Build Include="Tables\CheckConstraints\CheckConstraintIdentical.sql" />
     <Build Include="Tables\Triggers\TriggerIdentical.sql" />
     <Build Include="Tables\__EFMigrationsHistoryTarget.sql" />
+    <Build Include="Tables\TableWithDifferentPrimaryKey.sql" />
   </ItemGroup>
 </Project>

tests/Testing.Databases.SqlServer.Tests/SqlServerDatabaseComparerTest.CompareAsync.txt

@@ -114,7 +114,7 @@
       * Position:
           Source: 1
           Target: 2
-  ------ Primary keys ------
+  ------ Primary key ------
   - PrimaryKeyDifference
     * Type:
         Source: NONCLUSTERED
@@ -165,6 +165,15 @@
           Source: 1
           Target: 2
 - dbo.TableTarget (Missing in the source)
+- dbo.TableWithDifferentPrimaryKey
+  ------ Indexes ------
+  - PK_TableWithDifferentPrimaryKey_Target (Missing in the source)
+  - PK_TableWithDifferentPrimaryKey_Source (Missing in the target)
+  ------ Primary key ------
+  - PK_TableWithDifferentPrimaryKey_Source
+    * Name:
+        Source: PK_TableWithDifferentPrimaryKey_Source
+        Target: PK_TableWithDifferentPrimaryKey_Target
 - dbo.TableSource (Missing in the target)
 ------ Stored procedures ------
 - dbo.StoredProcedureDifference